* [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
@ 2023-07-04 6:19 syzbot
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
` (2 more replies)
0 siblings, 3 replies; 18+ messages in thread
From: syzbot @ 2023-07-04 6:19 UTC (permalink / raw)
To: davem, edumazet, kernel, kuba, linux-can, linux-kernel, linux,
mkl, netdev, pabeni, robin, socketcan, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: ae230642190a Merge branch 'af_unix-followup-fixes-for-so_p..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1771bf67280000
kernel config: https://syzkaller.appspot.com/x/.config?x=c9bf1936936ca698
dashboard link: https://syzkaller.appspot.com/bug?extid=1591462f226d9cbf0564
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c060db03f09/disk-ae230642.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1b9b937ece91/vmlinux-ae230642.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0c7eb1c82bf0/bzImage-ae230642.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc7-syzkaller-01948-gae230642190a #0 Not tainted
------------------------------------------------------
syz-executor.2/11224 is trying to acquire lock:
ffff88803bee50d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff88803bee50d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081
but task is already holding lock:
ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x41/0x360 net/can/j1939/transport.c:2183
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&priv->active_session_list_lock){+.-.}-{2:2}:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
j1939_session_activate+0x47/0x4b0 net/can/j1939/transport.c:1564
j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
j1939_sk_queue_activate_next+0x2bf/0x4d0 net/can/j1939/socket.c:208
j1939_session_deactivate_activate_next net/can/j1939/transport.c:1108 [inline]
j1939_xtp_rx_abort_one+0x3c0/0x5b0 net/can/j1939/transport.c:1351
j1939_xtp_rx_abort net/can/j1939/transport.c:1362 [inline]
j1939_tp_cmd_recv net/can/j1939/transport.c:2111 [inline]
j1939_tp_recv+0xd98/0xf50 net/can/j1939/transport.c:2144
j1939_can_recv net/can/j1939/main.c:112 [inline]
j1939_can_recv+0x78e/0xa80 net/can/j1939/main.c:38
deliver net/can/af_can.c:572 [inline]
can_rcv_filter+0x5d4/0x8d0 net/can/af_can.c:606
can_receive+0x31d/0x5c0 net/can/af_can.c:663
can_rcv+0x1e1/0x280 net/can/af_can.c:687
__netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5452
__netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5566
process_backlog+0x101/0x670 net/core/dev.c:5894
__napi_poll+0xb7/0x6f0 net/core/dev.c:6460
napi_poll net/core/dev.c:6527 [inline]
net_rx_action+0x8a9/0xcb0 net/core/dev.c:6660
__do_softirq+0x1d4/0x905 kernel/softirq.c:571
run_ksoftirqd kernel/softirq.c:939 [inline]
run_ksoftirqd+0x31/0x60 kernel/softirq.c:931
smpboot_thread_fn+0x659/0x9e0 kernel/smpboot.c:164
kthread+0x344/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
-> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_queue_drop_all+0x3b/0x2f0 net/can/j1939/socket.c:139
j1939_sk_netdev_event_netdown+0x7f/0x160 net/can/j1939/socket.c:1280
j1939_netdev_notify+0x19f/0x1d0 net/can/j1939/main.c:381
notifier_call_chain+0xb6/0x3c0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962
call_netdevice_notifiers_extack net/core/dev.c:2000 [inline]
call_netdevice_notifiers net/core/dev.c:2014 [inline]
__dev_notify_flags+0x1ea/0x2d0 net/core/dev.c:8571
dev_change_flags+0x11b/0x170 net/core/dev.c:8607
do_setlink+0x19e2/0x3ae0 net/core/rtnetlink.c:2867
__rtnl_newlink+0xd85/0x1860 net/core/rtnetlink.c:3655
rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3702
rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6424
netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:747
____sys_sendmsg+0x733/0x920 net/socket.c:2493
___sys_sendmsg+0x110/0x1b0 net/socket.c:2547
__sys_sendmsg+0xf7/0x1c0 net/socket.c:2576
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088
lock_acquire kernel/locking/lockdep.c:5705 [inline]
lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081
j1939_session_destroy+0x26c/0x4e0 net/can/j1939/transport.c:271
__j1939_session_release net/can/j1939/transport.c:294 [inline]
kref_put include/linux/kref.h:65 [inline]
j1939_session_put net/can/j1939/transport.c:299 [inline]
j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
j1939_session_deactivate_locked+0x293/0x340 net/can/j1939/transport.c:1074
j1939_cancel_active_session+0x183/0x360 net/can/j1939/transport.c:2194
j1939_netdev_notify+0x197/0x1d0 net/can/j1939/main.c:380
notifier_call_chain+0xb6/0x3c0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962
call_netdevice_notifiers_extack net/core/dev.c:2000 [inline]
call_netdevice_notifiers net/core/dev.c:2014 [inline]
__dev_notify_flags+0x1ea/0x2d0 net/core/dev.c:8571
dev_change_flags+0x11b/0x170 net/core/dev.c:8607
do_setlink+0x19e2/0x3ae0 net/core/rtnetlink.c:2867
__rtnl_newlink+0xd85/0x1860 net/core/rtnetlink.c:3655
rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3702
rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6424
netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:747
____sys_sendmsg+0x733/0x920 net/socket.c:2493
___sys_sendmsg+0x110/0x1b0 net/socket.c:2547
__sys_sendmsg+0xf7/0x1c0 net/socket.c:2576
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Chain exists of:
&priv->j1939_socks_lock --> &jsk->sk_session_queue_lock --> &priv->active_session_list_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&priv->active_session_list_lock);
lock(&jsk->sk_session_queue_lock);
lock(&priv->active_session_list_lock);
lock(&priv->j1939_socks_lock);
*** DEADLOCK ***
2 locks held by syz-executor.2/11224:
#0: ffffffff8e1194a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffffffff8e1194a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3e8/0xd50 net/core/rtnetlink.c:6421
#1: ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
#1: ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
#1: ffff88803bee5088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x41/0x360 net/can/j1939/transport.c:2183
stack backtrace:
CPU: 1 PID: 11224 Comm: syz-executor.2 Not tainted 6.4.0-rc7-syzkaller-01948-gae230642190a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088
lock_acquire kernel/locking/lockdep.c:5705 [inline]
lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_errqueue+0xa3/0x1a0 net/can/j1939/socket.c:1081
j1939_session_destroy+0x26c/0x4e0 net/can/j1939/transport.c:271
__j1939_session_release net/can/j1939/transport.c:294 [inline]
kref_put include/linux/kref.h:65 [inline]
j1939_session_put net/can/j1939/transport.c:299 [inline]
j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
j1939_session_deactivate_locked+0x293/0x340 net/can/j1939/transport.c:1074
j1939_cancel_active_session+0x183/0x360 net/can/j1939/transport.c:2194
j1939_netdev_notify+0x197/0x1d0 net/can/j1939/main.c:380
notifier_call_chain+0xb6/0x3c0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962
call_netdevice_notifiers_extack net/core/dev.c:2000 [inline]
call_netdevice_notifiers net/core/dev.c:2014 [inline]
__dev_notify_flags+0x1ea/0x2d0 net/core/dev.c:8571
dev_change_flags+0x11b/0x170 net/core/dev.c:8607
do_setlink+0x19e2/0x3ae0 net/core/rtnetlink.c:2867
__rtnl_newlink+0xd85/0x1860 net/core/rtnetlink.c:3655
rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3702
rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6424
netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:747
____sys_sendmsg+0x733/0x920 net/socket.c:2493
___sys_sendmsg+0x110/0x1b0 net/socket.c:2547
__sys_sendmsg+0xf7/0x1c0 net/socket.c:2576
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fdb2bc8c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdb2cab9168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fdb2bdabf80 RCX: 00007fdb2bc8c389
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000006
RBP: 00007fdb2bcd7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd70d89bbf R14: 00007fdb2cab9300 R15: 0000000000022000
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-04 6:19 [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
@ 2023-07-04 6:47 ` Ziqi Zhao
2023-07-04 6:47 ` syzbot
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
2023-07-10 17:53 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-11-15 3:54 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2 siblings, 2 replies; 18+ messages in thread
From: Ziqi Zhao @ 2023-07-04 6:47 UTC (permalink / raw)
To: syzbot+1591462f226d9cbf0564
Cc: davem, edumazet, kernel, kuba, linux-can, linux-kernel, linux,
mkl, netdev, pabeni, robin, socketcan, syzkaller-bugs, skhan,
ivan.orlov0322, Ziqi Zhao
The following 3 locks would race against each other, causing the
deadlock situation in the Syzbot bug report:
- j1939_socks_lock
- active_session_list_lock
- sk_session_queue_lock
A reasonable fix is to change j1939_socks_lock to an rwlock, since in
the rare situations where a write lock is required for the linked list
that j1939_socks_lock is protecting, the code does not attempt to
acquire any more locks. This would break the circular lock dependency,
where, for example, the current thread already locks j1939_socks_lock
and attempts to acquire sk_session_queue_lock, and at the same time,
another thread attempts to acquire j1939_socks_lock while holding
sk_session_queue_lock.
NOTE: This patch along does not fix the unregister_netdevice bug
reported by Syzbot; instead, it solves a deadlock situation to prepare
for one or more further patches to actually fix the Syzbot bug, which
appears to be a reference counting problem within the j1939 codebase.
#syz test:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
---
net/can/j1939/j1939-priv.h | 2 +-
net/can/j1939/main.c | 2 +-
net/can/j1939/socket.c | 25 +++++++++++++------------
3 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
index 16af1a7f80f6..74f15592d170 100644
--- a/net/can/j1939/j1939-priv.h
+++ b/net/can/j1939/j1939-priv.h
@@ -86,7 +86,7 @@ struct j1939_priv {
unsigned int tp_max_packet_size;
/* lock for j1939_socks list */
- spinlock_t j1939_socks_lock;
+ rwlock_t j1939_socks_lock;
struct list_head j1939_socks;
struct kref rx_kref;
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index ecff1c947d68..a6fb89fa6278 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
return ERR_PTR(-ENOMEM);
j1939_tp_init(priv);
- spin_lock_init(&priv->j1939_socks_lock);
+ rwlock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
mutex_lock(&j1939_netdev_lock);
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index feaec4ad6d16..a8b981dc2065 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
jsk->state |= J1939_SOCK_BOUND;
j1939_priv_get(priv);
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_add_tail(&jsk->list, &priv->j1939_socks);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
{
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_del_init(&jsk->list);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
j1939_priv_put(priv);
jsk->state &= ~J1939_SOCK_BOUND;
@@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
struct j1939_sock *jsk;
bool match = false;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
match = j1939_sk_recv_match_one(jsk, skcb);
if (match)
break;
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
return match;
}
@@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sock *jsk;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
j1939_sk_recv_one(jsk, skb);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_sk_sock_destruct(struct sock *sk)
@@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
priv = j1939_netdev_start(ndev);
dev_put(ndev);
+
if (IS_ERR(priv)) {
ret = PTR_ERR(priv);
goto out_release_sock;
@@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
}
/* spread RX notifications to all sockets subscribed to this session */
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
if (j1939_sk_recv_match_one(jsk, &session->skcb))
__j1939_sk_errqueue(session, &jsk->sk, type);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
};
void j1939_sk_send_loop_abort(struct sock *sk, int err)
@@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
struct j1939_sock *jsk;
int error_code = ENETDOWN;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
jsk->sk.sk_err = error_code;
if (!sock_flag(&jsk->sk, SOCK_DEAD))
@@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
j1939_sk_queue_drop_all(priv, jsk, error_code);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
--
2.34.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
@ 2023-07-04 6:47 ` syzbot
2023-07-04 7:37 ` Oleksij Rempel
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
1 sibling, 1 reply; 18+ messages in thread
From: syzbot @ 2023-07-04 6:47 UTC (permalink / raw)
To: astrajoan
Cc: astrajoan, davem, edumazet, ivan.orlov0322, kernel, kuba,
linux-can, linux-kernel, linux, mkl, netdev, pabeni, robin,
skhan, socketcan, syzkaller-bugs
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> #syz test:
This crash does not have a reproducer. I cannot test it.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
> ---
> net/can/j1939/j1939-priv.h | 2 +-
> net/can/j1939/main.c | 2 +-
> net/can/j1939/socket.c | 25 +++++++++++++------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 16af1a7f80f6..74f15592d170 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -86,7 +86,7 @@ struct j1939_priv {
> unsigned int tp_max_packet_size;
>
> /* lock for j1939_socks list */
> - spinlock_t j1939_socks_lock;
> + rwlock_t j1939_socks_lock;
> struct list_head j1939_socks;
>
> struct kref rx_kref;
> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> index ecff1c947d68..a6fb89fa6278 100644
> --- a/net/can/j1939/main.c
> +++ b/net/can/j1939/main.c
> @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
> return ERR_PTR(-ENOMEM);
>
> j1939_tp_init(priv);
> - spin_lock_init(&priv->j1939_socks_lock);
> + rwlock_init(&priv->j1939_socks_lock);
> INIT_LIST_HEAD(&priv->j1939_socks);
>
> mutex_lock(&j1939_netdev_lock);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index feaec4ad6d16..a8b981dc2065 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
> jsk->state |= J1939_SOCK_BOUND;
> j1939_priv_get(priv);
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_add_tail(&jsk->list, &priv->j1939_socks);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
> {
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_del_init(&jsk->list);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
>
> j1939_priv_put(priv);
> jsk->state &= ~J1939_SOCK_BOUND;
> @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
> struct j1939_sock *jsk;
> bool match = false;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> match = j1939_sk_recv_match_one(jsk, skcb);
> if (match)
> break;
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
>
> return match;
> }
> @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
> {
> struct j1939_sock *jsk;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> j1939_sk_recv_one(jsk, skb);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_sk_sock_destruct(struct sock *sk)
> @@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
>
> priv = j1939_netdev_start(ndev);
> dev_put(ndev);
> +
> if (IS_ERR(priv)) {
> ret = PTR_ERR(priv);
> goto out_release_sock;
> @@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
> }
>
> /* spread RX notifications to all sockets subscribed to this session */
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> if (j1939_sk_recv_match_one(jsk, &session->skcb))
> __j1939_sk_errqueue(session, &jsk->sk, type);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> };
>
> void j1939_sk_send_loop_abort(struct sock *sk, int err)
> @@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
> struct j1939_sock *jsk;
> int error_code = ENETDOWN;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> jsk->sk.sk_err = error_code;
> if (!sock_flag(&jsk->sk, SOCK_DEAD))
> @@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
>
> j1939_sk_queue_drop_all(priv, jsk, error_code);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-04 6:47 ` syzbot
@ 2023-07-04 7:37 ` Oleksij Rempel
0 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-07-04 7:37 UTC (permalink / raw)
To: syzbot
Cc: astrajoan, davem, edumazet, ivan.orlov0322, kernel, kuba,
linux-can, linux-kernel, linux, mkl, netdev, pabeni, robin,
skhan, socketcan, syzkaller-bugs
On Mon, Jul 03, 2023 at 11:47:26PM -0700, syzbot wrote:
> > The following 3 locks would race against each other, causing the
> > deadlock situation in the Syzbot bug report:
> >
> > - j1939_socks_lock
> > - active_session_list_lock
> > - sk_session_queue_lock
> >
> > A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> > the rare situations where a write lock is required for the linked list
> > that j1939_socks_lock is protecting, the code does not attempt to
> > acquire any more locks. This would break the circular lock dependency,
> > where, for example, the current thread already locks j1939_socks_lock
> > and attempts to acquire sk_session_queue_lock, and at the same time,
> > another thread attempts to acquire j1939_socks_lock while holding
> > sk_session_queue_lock.
> >
> > NOTE: This patch along does not fix the unregister_netdevice bug
> > reported by Syzbot; instead, it solves a deadlock situation to prepare
> > for one or more further patches to actually fix the Syzbot bug, which
> > appears to be a reference counting problem within the j1939 codebase.
> >
> > #syz test:
>
> This crash does not have a reproducer. I cannot test it.
>
To stress this code path, the socket should be configured with err queue
enabled. For example like this:
value = 1;
setsockopt(priv->sock, SOL_CAN_J1939, SO_J1939_ERRQUEUE, &value,
sizeof(value));
sock_opt = SOF_TIMESTAMPING_SOFTWARE |
SOF_TIMESTAMPING_OPT_CMSG |
SOF_TIMESTAMPING_TX_ACK |
SOF_TIMESTAMPING_TX_SCHED |
SOF_TIMESTAMPING_OPT_STATS | SOF_TIMESTAMPING_OPT_TSONLY |
SOF_TIMESTAMPING_OPT_ID | SOF_TIMESTAMPING_RX_SOFTWARE;
setsockopt(priv->sock, SOL_SOCKET, SO_TIMESTAMPING,
(char *) &sock_opt, sizeof(sock_opt));
I hope it will help to create the reproducer
Regards,
Oleksij
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
2023-07-04 6:19 [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
@ 2023-07-10 17:53 ` syzbot
2023-07-12 0:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
2023-11-15 3:54 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2 siblings, 1 reply; 18+ messages in thread
From: syzbot @ 2023-07-10 17:53 UTC (permalink / raw)
To: astrajoan, davem, dvyukov, edumazet, ivan.orlov0322, kernel,
kuba, linux-can, linux-kernel, linux, mkl, netdev, o.rempel,
pabeni, robin, skhan, socketcan, syzkaller-bugs, syzkaller
syzbot has found a reproducer for the following issue on:
HEAD commit: e40939bbfc68 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=17ce67d8a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c84f463eb74eab24
dashboard link: https://syzkaller.appspot.com/bug?extid=1591462f226d9cbf0564
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1580fc5ca80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=178f78d4a80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/257596b75aaf/disk-e40939bb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9c75b8d61081/vmlinux-e40939bb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f0233129f4f/Image-e40939bb.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.4.0-rc7-syzkaller-ge40939bbfc68 #0 Not tainted
------------------------------------------------------
syz-executor375/6045 is trying to acquire lock:
ffff0000d2e690d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff0000d2e690d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1081
but task is already holding lock:
ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&priv->active_session_list_lock){+.-.}-{2:2}:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
j1939_session_activate+0x60/0x378 net/can/j1939/transport.c:1564
j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline]
j1939_sk_queue_activate_next+0x230/0x3b4 net/can/j1939/socket.c:208
j1939_session_deactivate_activate_next net/can/j1939/transport.c:1108 [inline]
j1939_session_completed net/can/j1939/transport.c:1222 [inline]
j1939_xtp_rx_eoma_one net/can/j1939/transport.c:1395 [inline]
j1939_xtp_rx_eoma+0x2c0/0x4c0 net/can/j1939/transport.c:1410
j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline]
j1939_tp_recv+0x714/0xe14 net/can/j1939/transport.c:2144
j1939_can_recv+0x5bc/0x930 net/can/j1939/main.c:112
deliver net/can/af_can.c:572 [inline]
can_rcv_filter+0x308/0x714 net/can/af_can.c:606
can_receive+0x338/0x498 net/can/af_can.c:663
can_rcv+0x128/0x23c net/can/af_can.c:687
__netif_receive_skb_one_core net/core/dev.c:5493 [inline]
__netif_receive_skb+0x18c/0x400 net/core/dev.c:5607
process_backlog+0x3c0/0x70c net/core/dev.c:5935
__napi_poll+0xb4/0x648 net/core/dev.c:6498
napi_poll net/core/dev.c:6565 [inline]
net_rx_action+0x5e4/0xdc4 net/core/dev.c:6698
__do_softirq+0x2d0/0xd54 kernel/softirq.c:571
run_ksoftirqd+0x6c/0x158 kernel/softirq.c:939
smpboot_thread_fn+0x4b0/0x920 kernel/smpboot.c:164
kthread+0x288/0x310 kernel/kthread.c:379
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:853
-> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_queue_drop_all+0x4c/0x200 net/can/j1939/socket.c:139
j1939_sk_netdev_event_netdown+0xe0/0x144 net/can/j1939/socket.c:1280
j1939_netdev_notify+0xf0/0x144 net/can/j1939/main.c:381
notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461
__dev_notify_flags+0x2bc/0x544
dev_change_flags+0xd0/0x15c net/core/dev.c:8645
do_setlink+0xc68/0x35c8 net/core/rtnetlink.c:2867
__rtnl_newlink net/core/rtnetlink.c:3648 [inline]
rtnl_newlink+0x1354/0x1b1c net/core/rtnetlink.c:3695
rtnetlink_rcv_msg+0x744/0xdb8 net/core/rtnetlink.c:6417
netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6435
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x568/0x81c net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x26c/0x33c net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2593
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
-> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1081
__j1939_session_release net/can/j1939/transport.c:294 [inline]
kref_put include/linux/kref.h:65 [inline]
j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299
j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194
j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380
notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461
__dev_notify_flags+0x2bc/0x544
dev_change_flags+0xd0/0x15c net/core/dev.c:8645
do_setlink+0xc68/0x35c8 net/core/rtnetlink.c:2867
__rtnl_newlink net/core/rtnetlink.c:3648 [inline]
rtnl_newlink+0x1354/0x1b1c net/core/rtnetlink.c:3695
rtnetlink_rcv_msg+0x744/0xdb8 net/core/rtnetlink.c:6417
netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6435
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x568/0x81c net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x26c/0x33c net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2593
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
other info that might help us debug this:
Chain exists of:
&priv->j1939_socks_lock --> &jsk->sk_session_queue_lock --> &priv->active_session_list_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&priv->active_session_list_lock);
lock(&jsk->sk_session_queue_lock);
lock(&priv->active_session_list_lock);
lock(&priv->j1939_socks_lock);
*** DEADLOCK ***
2 locks held by syz-executor375/6045:
#0: ffff80009080db68 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffff80009080db68 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x700/0xdb8 net/core/rtnetlink.c:6414
#1: ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
#1: ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
#1: ffff0000d2e69088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183
stack backtrace:
CPU: 1 PID: 6045 Comm: syz-executor375 Not tainted 6.4.0-rc7-syzkaller-ge40939bbfc68 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call trace:
dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
dump_stack+0x1c/0x28 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2066
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2188
check_prev_add kernel/locking/lockdep.c:3113 [inline]
check_prevs_add kernel/locking/lockdep.c:3232 [inline]
validate_chain kernel/locking/lockdep.c:3847 [inline]
__lock_acquire+0x3308/0x7604 kernel/locking/lockdep.c:5088
lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5705
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1081
__j1939_session_release net/can/j1939/transport.c:294 [inline]
kref_put include/linux/kref.h:65 [inline]
j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299
j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline]
j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194
j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380
notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93
raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461
__dev_notify_flags+0x2bc/0x544
dev_change_flags+0xd0/0x15c net/core/dev.c:8645
do_setlink+0xc68/0x35c8 net/core/rtnetlink.c:2867
__rtnl_newlink net/core/rtnetlink.c:3648 [inline]
rtnl_newlink+0x1354/0x1b1c net/core/rtnetlink.c:3695
rtnetlink_rcv_msg+0x744/0xdb8 net/core/rtnetlink.c:6417
netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6435
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x568/0x81c net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x26c/0x33c net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2593
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x244 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:191
el0_svc+0x4c/0x160 arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-10 17:53 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
@ 2023-07-12 0:47 ` Ziqi Zhao
2023-07-12 1:16 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-13 22:23 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Stephen Hemminger
0 siblings, 2 replies; 18+ messages in thread
From: Ziqi Zhao @ 2023-07-12 0:47 UTC (permalink / raw)
To: syzbot+1591462f226d9cbf0564
Cc: astrajoan, davem, dvyukov, edumazet, ivan.orlov0322, kernel,
kuba, linux-can, linux-kernel, linux, mkl, netdev, o.rempel,
pabeni, robin, skhan, socketcan, syzkaller-bugs, syzkaller
The following 3 locks would race against each other, causing the
deadlock situation in the Syzbot bug report:
- j1939_socks_lock
- active_session_list_lock
- sk_session_queue_lock
A reasonable fix is to change j1939_socks_lock to an rwlock, since in
the rare situations where a write lock is required for the linked list
that j1939_socks_lock is protecting, the code does not attempt to
acquire any more locks. This would break the circular lock dependency,
where, for example, the current thread already locks j1939_socks_lock
and attempts to acquire sk_session_queue_lock, and at the same time,
another thread attempts to acquire j1939_socks_lock while holding
sk_session_queue_lock.
NOTE: This patch along does not fix the unregister_netdevice bug
reported by Syzbot; instead, it solves a deadlock situation to prepare
for one or more further patches to actually fix the Syzbot bug, which
appears to be a reference counting problem within the j1939 codebase.
#syz test:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
---
net/can/j1939/j1939-priv.h | 2 +-
net/can/j1939/main.c | 2 +-
net/can/j1939/socket.c | 25 +++++++++++++------------
3 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
index 16af1a7f80f6..74f15592d170 100644
--- a/net/can/j1939/j1939-priv.h
+++ b/net/can/j1939/j1939-priv.h
@@ -86,7 +86,7 @@ struct j1939_priv {
unsigned int tp_max_packet_size;
/* lock for j1939_socks list */
- spinlock_t j1939_socks_lock;
+ rwlock_t j1939_socks_lock;
struct list_head j1939_socks;
struct kref rx_kref;
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index ecff1c947d68..a6fb89fa6278 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
return ERR_PTR(-ENOMEM);
j1939_tp_init(priv);
- spin_lock_init(&priv->j1939_socks_lock);
+ rwlock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
mutex_lock(&j1939_netdev_lock);
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index feaec4ad6d16..a8b981dc2065 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
jsk->state |= J1939_SOCK_BOUND;
j1939_priv_get(priv);
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_add_tail(&jsk->list, &priv->j1939_socks);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
{
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_del_init(&jsk->list);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
j1939_priv_put(priv);
jsk->state &= ~J1939_SOCK_BOUND;
@@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
struct j1939_sock *jsk;
bool match = false;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
match = j1939_sk_recv_match_one(jsk, skcb);
if (match)
break;
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
return match;
}
@@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sock *jsk;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
j1939_sk_recv_one(jsk, skb);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_sk_sock_destruct(struct sock *sk)
@@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
priv = j1939_netdev_start(ndev);
dev_put(ndev);
+
if (IS_ERR(priv)) {
ret = PTR_ERR(priv);
goto out_release_sock;
@@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
}
/* spread RX notifications to all sockets subscribed to this session */
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
if (j1939_sk_recv_match_one(jsk, &session->skcb))
__j1939_sk_errqueue(session, &jsk->sk, type);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
};
void j1939_sk_send_loop_abort(struct sock *sk, int err)
@@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
struct j1939_sock *jsk;
int error_code = ENETDOWN;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
jsk->sk.sk_err = error_code;
if (!sock_flag(&jsk->sk, SOCK_DEAD))
@@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
j1939_sk_queue_drop_all(priv, jsk, error_code);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
--
2.34.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
2023-07-12 0:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
@ 2023-07-12 1:16 ` syzbot
2023-07-13 22:23 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Stephen Hemminger
1 sibling, 0 replies; 18+ messages in thread
From: syzbot @ 2023-07-12 1:16 UTC (permalink / raw)
To: astrajoan, davem, dvyukov, edumazet, ivan.orlov0322, kernel,
kuba, linux-can, linux-kernel, linux, mkl, netdev, o.rempel,
pabeni, robin, skhan, socketcan, syzkaller-bugs, syzkaller
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
Tested on:
commit: 3f01e9fe Merge tag 'linux-watchdog-6.5-rc2' of git://w..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=130a98a2a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=4c2acb092ca90577
dashboard link: https://syzkaller.appspot.com/bug?extid=1591462f226d9cbf0564
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
patch: https://syzkaller.appspot.com/x/patch.diff?x=1380a782a80000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-12 0:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
2023-07-12 1:16 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
@ 2023-07-13 22:23 ` Stephen Hemminger
1 sibling, 0 replies; 18+ messages in thread
From: Stephen Hemminger @ 2023-07-13 22:23 UTC (permalink / raw)
To: Ziqi Zhao
Cc: syzbot+1591462f226d9cbf0564, davem, dvyukov, edumazet,
ivan.orlov0322, kernel, kuba, linux-can, linux-kernel, linux,
mkl, netdev, o.rempel, pabeni, robin, skhan, socketcan,
syzkaller-bugs, syzkaller
On Tue, 11 Jul 2023 17:47:50 -0700
Ziqi Zhao <astrajoan@yahoo.com> wrote:
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> #syz test:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
> ---
Reader-writer locks are not the best way to fix a lock hierarchy problem.
Instead either fix the lock ordering, or use RCU.
Other devices don't have this problem, so perhaps the unique locking
in this device is the problem.
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
@ 2023-07-21 16:22 ` Ziqi Zhao
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
1 sibling, 0 replies; 18+ messages in thread
From: Ziqi Zhao @ 2023-07-21 16:22 UTC (permalink / raw)
To: astrajoan, davem, edumazet, ivan.orlov0322, kernel, kuba, linux,
linux-can, mkl, pabeni, robin, skhan, socketcan
Cc: arnd, bridge, linux-kernel, mudongliangabcd, netdev, nikolay,
roopa, syzbot+881d65229ca4f9ae8c84, syzkaller-bugs,
syzbot+1591462f226d9cbf0564
The following 3 locks would race against each other, causing the
deadlock situation in the Syzbot bug report:
- j1939_socks_lock
- active_session_list_lock
- sk_session_queue_lock
A reasonable fix is to change j1939_socks_lock to an rwlock, since in
the rare situations where a write lock is required for the linked list
that j1939_socks_lock is protecting, the code does not attempt to
acquire any more locks. This would break the circular lock dependency,
where, for example, the current thread already locks j1939_socks_lock
and attempts to acquire sk_session_queue_lock, and at the same time,
another thread attempts to acquire j1939_socks_lock while holding
sk_session_queue_lock.
NOTE: This patch along does not fix the unregister_netdevice bug
reported by Syzbot; instead, it solves a deadlock situation to prepare
for one or more further patches to actually fix the Syzbot bug, which
appears to be a reference counting problem within the j1939 codebase.
Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
---
net/can/j1939/j1939-priv.h | 2 +-
net/can/j1939/main.c | 2 +-
net/can/j1939/socket.c | 25 +++++++++++++------------
3 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
index 16af1a7f80f6..74f15592d170 100644
--- a/net/can/j1939/j1939-priv.h
+++ b/net/can/j1939/j1939-priv.h
@@ -86,7 +86,7 @@ struct j1939_priv {
unsigned int tp_max_packet_size;
/* lock for j1939_socks list */
- spinlock_t j1939_socks_lock;
+ rwlock_t j1939_socks_lock;
struct list_head j1939_socks;
struct kref rx_kref;
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index ecff1c947d68..a6fb89fa6278 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
return ERR_PTR(-ENOMEM);
j1939_tp_init(priv);
- spin_lock_init(&priv->j1939_socks_lock);
+ rwlock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
mutex_lock(&j1939_netdev_lock);
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index feaec4ad6d16..a8b981dc2065 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
jsk->state |= J1939_SOCK_BOUND;
j1939_priv_get(priv);
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_add_tail(&jsk->list, &priv->j1939_socks);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
{
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_del_init(&jsk->list);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
j1939_priv_put(priv);
jsk->state &= ~J1939_SOCK_BOUND;
@@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
struct j1939_sock *jsk;
bool match = false;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
match = j1939_sk_recv_match_one(jsk, skcb);
if (match)
break;
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
return match;
}
@@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sock *jsk;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
j1939_sk_recv_one(jsk, skb);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_sk_sock_destruct(struct sock *sk)
@@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
priv = j1939_netdev_start(ndev);
dev_put(ndev);
+
if (IS_ERR(priv)) {
ret = PTR_ERR(priv);
goto out_release_sock;
@@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
}
/* spread RX notifications to all sockets subscribed to this session */
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
if (j1939_sk_recv_match_one(jsk, &session->skcb))
__j1939_sk_errqueue(session, &jsk->sk, type);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
};
void j1939_sk_send_loop_abort(struct sock *sk, int err)
@@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
struct j1939_sock *jsk;
int error_code = ENETDOWN;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
jsk->sk.sk_err = error_code;
if (!sock_flag(&jsk->sk, SOCK_DEAD))
@@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
j1939_sk_queue_drop_all(priv, jsk, error_code);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
--
2.34.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [Bridge] [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
@ 2023-07-21 16:22 ` Ziqi Zhao
0 siblings, 0 replies; 18+ messages in thread
From: Ziqi Zhao @ 2023-07-21 16:22 UTC (permalink / raw)
To: astrajoan, davem, edumazet, ivan.orlov0322, kernel, kuba, linux,
linux-can, mkl, pabeni, robin, skhan, socketcan
Cc: arnd, netdev, bridge, syzkaller-bugs, linux-kernel,
mudongliangabcd, nikolay, syzbot+1591462f226d9cbf0564, roopa,
syzbot+881d65229ca4f9ae8c84
The following 3 locks would race against each other, causing the
deadlock situation in the Syzbot bug report:
- j1939_socks_lock
- active_session_list_lock
- sk_session_queue_lock
A reasonable fix is to change j1939_socks_lock to an rwlock, since in
the rare situations where a write lock is required for the linked list
that j1939_socks_lock is protecting, the code does not attempt to
acquire any more locks. This would break the circular lock dependency,
where, for example, the current thread already locks j1939_socks_lock
and attempts to acquire sk_session_queue_lock, and at the same time,
another thread attempts to acquire j1939_socks_lock while holding
sk_session_queue_lock.
NOTE: This patch along does not fix the unregister_netdevice bug
reported by Syzbot; instead, it solves a deadlock situation to prepare
for one or more further patches to actually fix the Syzbot bug, which
appears to be a reference counting problem within the j1939 codebase.
Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
---
net/can/j1939/j1939-priv.h | 2 +-
net/can/j1939/main.c | 2 +-
net/can/j1939/socket.c | 25 +++++++++++++------------
3 files changed, 15 insertions(+), 14 deletions(-)
diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
index 16af1a7f80f6..74f15592d170 100644
--- a/net/can/j1939/j1939-priv.h
+++ b/net/can/j1939/j1939-priv.h
@@ -86,7 +86,7 @@ struct j1939_priv {
unsigned int tp_max_packet_size;
/* lock for j1939_socks list */
- spinlock_t j1939_socks_lock;
+ rwlock_t j1939_socks_lock;
struct list_head j1939_socks;
struct kref rx_kref;
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index ecff1c947d68..a6fb89fa6278 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
return ERR_PTR(-ENOMEM);
j1939_tp_init(priv);
- spin_lock_init(&priv->j1939_socks_lock);
+ rwlock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
mutex_lock(&j1939_netdev_lock);
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index feaec4ad6d16..a8b981dc2065 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
jsk->state |= J1939_SOCK_BOUND;
j1939_priv_get(priv);
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_add_tail(&jsk->list, &priv->j1939_socks);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
{
- spin_lock_bh(&priv->j1939_socks_lock);
+ write_lock_bh(&priv->j1939_socks_lock);
list_del_init(&jsk->list);
- spin_unlock_bh(&priv->j1939_socks_lock);
+ write_unlock_bh(&priv->j1939_socks_lock);
j1939_priv_put(priv);
jsk->state &= ~J1939_SOCK_BOUND;
@@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
struct j1939_sock *jsk;
bool match = false;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
match = j1939_sk_recv_match_one(jsk, skcb);
if (match)
break;
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
return match;
}
@@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sock *jsk;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
j1939_sk_recv_one(jsk, skb);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static void j1939_sk_sock_destruct(struct sock *sk)
@@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
priv = j1939_netdev_start(ndev);
dev_put(ndev);
+
if (IS_ERR(priv)) {
ret = PTR_ERR(priv);
goto out_release_sock;
@@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
}
/* spread RX notifications to all sockets subscribed to this session */
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
if (j1939_sk_recv_match_one(jsk, &session->skcb))
__j1939_sk_errqueue(session, &jsk->sk, type);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
};
void j1939_sk_send_loop_abort(struct sock *sk, int err)
@@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
struct j1939_sock *jsk;
int error_code = ENETDOWN;
- spin_lock_bh(&priv->j1939_socks_lock);
+ read_lock_bh(&priv->j1939_socks_lock);
list_for_each_entry(jsk, &priv->j1939_socks, list) {
jsk->sk.sk_err = error_code;
if (!sock_flag(&jsk->sk, SOCK_DEAD))
@@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
j1939_sk_queue_drop_all(priv, jsk, error_code);
}
- spin_unlock_bh(&priv->j1939_socks_lock);
+ read_unlock_bh(&priv->j1939_socks_lock);
}
static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
--
2.34.1
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
@ 2023-07-23 15:41 ` Oleksij Rempel
-1 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-07-23 15:41 UTC (permalink / raw)
To: Ziqi Zhao
Cc: davem, edumazet, ivan.orlov0322, kernel, kuba, linux, linux-can,
mkl, pabeni, robin, skhan, socketcan, arnd, bridge, linux-kernel,
mudongliangabcd, netdev, nikolay, roopa,
syzbot+881d65229ca4f9ae8c84, syzkaller-bugs,
syzbot+1591462f226d9cbf0564
Hi,
Thank you for you patch. Right now I'm on vacation, I'll to take a look
on it as soon as possible. If i do not response for more then 3 weeks,
please ping me.
On Fri, Jul 21, 2023 at 09:22:26AM -0700, Ziqi Zhao wrote:
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
> ---
> net/can/j1939/j1939-priv.h | 2 +-
> net/can/j1939/main.c | 2 +-
> net/can/j1939/socket.c | 25 +++++++++++++------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 16af1a7f80f6..74f15592d170 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -86,7 +86,7 @@ struct j1939_priv {
> unsigned int tp_max_packet_size;
>
> /* lock for j1939_socks list */
> - spinlock_t j1939_socks_lock;
> + rwlock_t j1939_socks_lock;
> struct list_head j1939_socks;
>
> struct kref rx_kref;
> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> index ecff1c947d68..a6fb89fa6278 100644
> --- a/net/can/j1939/main.c
> +++ b/net/can/j1939/main.c
> @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
> return ERR_PTR(-ENOMEM);
>
> j1939_tp_init(priv);
> - spin_lock_init(&priv->j1939_socks_lock);
> + rwlock_init(&priv->j1939_socks_lock);
> INIT_LIST_HEAD(&priv->j1939_socks);
>
> mutex_lock(&j1939_netdev_lock);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index feaec4ad6d16..a8b981dc2065 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
> jsk->state |= J1939_SOCK_BOUND;
> j1939_priv_get(priv);
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_add_tail(&jsk->list, &priv->j1939_socks);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
> {
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_del_init(&jsk->list);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
>
> j1939_priv_put(priv);
> jsk->state &= ~J1939_SOCK_BOUND;
> @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
> struct j1939_sock *jsk;
> bool match = false;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> match = j1939_sk_recv_match_one(jsk, skcb);
> if (match)
> break;
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
>
> return match;
> }
> @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
> {
> struct j1939_sock *jsk;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> j1939_sk_recv_one(jsk, skb);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_sk_sock_destruct(struct sock *sk)
> @@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
>
> priv = j1939_netdev_start(ndev);
> dev_put(ndev);
> +
> if (IS_ERR(priv)) {
> ret = PTR_ERR(priv);
> goto out_release_sock;
> @@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
> }
>
> /* spread RX notifications to all sockets subscribed to this session */
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> if (j1939_sk_recv_match_one(jsk, &session->skcb))
> __j1939_sk_errqueue(session, &jsk->sk, type);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> };
>
> void j1939_sk_send_loop_abort(struct sock *sk, int err)
> @@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
> struct j1939_sock *jsk;
> int error_code = ENETDOWN;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> jsk->sk.sk_err = error_code;
> if (!sock_flag(&jsk->sk, SOCK_DEAD))
> @@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
>
> j1939_sk_queue_drop_all(priv, jsk, error_code);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
> --
> 2.34.1
>
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [Bridge] [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
@ 2023-07-23 15:41 ` Oleksij Rempel
0 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-07-23 15:41 UTC (permalink / raw)
To: Ziqi Zhao
Cc: ivan.orlov0322, edumazet, syzbot+881d65229ca4f9ae8c84, socketcan,
bridge, nikolay, syzbot+1591462f226d9cbf0564, roopa, kuba,
pabeni, arnd, syzkaller-bugs, mudongliangabcd, linux-can, mkl,
skhan, robin, linux-kernel, linux, kernel, netdev, davem
Hi,
Thank you for you patch. Right now I'm on vacation, I'll to take a look
on it as soon as possible. If i do not response for more then 3 weeks,
please ping me.
On Fri, Jul 21, 2023 at 09:22:26AM -0700, Ziqi Zhao wrote:
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
> ---
> net/can/j1939/j1939-priv.h | 2 +-
> net/can/j1939/main.c | 2 +-
> net/can/j1939/socket.c | 25 +++++++++++++------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 16af1a7f80f6..74f15592d170 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -86,7 +86,7 @@ struct j1939_priv {
> unsigned int tp_max_packet_size;
>
> /* lock for j1939_socks list */
> - spinlock_t j1939_socks_lock;
> + rwlock_t j1939_socks_lock;
> struct list_head j1939_socks;
>
> struct kref rx_kref;
> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> index ecff1c947d68..a6fb89fa6278 100644
> --- a/net/can/j1939/main.c
> +++ b/net/can/j1939/main.c
> @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
> return ERR_PTR(-ENOMEM);
>
> j1939_tp_init(priv);
> - spin_lock_init(&priv->j1939_socks_lock);
> + rwlock_init(&priv->j1939_socks_lock);
> INIT_LIST_HEAD(&priv->j1939_socks);
>
> mutex_lock(&j1939_netdev_lock);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index feaec4ad6d16..a8b981dc2065 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
> jsk->state |= J1939_SOCK_BOUND;
> j1939_priv_get(priv);
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_add_tail(&jsk->list, &priv->j1939_socks);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
> {
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_del_init(&jsk->list);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
>
> j1939_priv_put(priv);
> jsk->state &= ~J1939_SOCK_BOUND;
> @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
> struct j1939_sock *jsk;
> bool match = false;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> match = j1939_sk_recv_match_one(jsk, skcb);
> if (match)
> break;
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
>
> return match;
> }
> @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
> {
> struct j1939_sock *jsk;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> j1939_sk_recv_one(jsk, skb);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_sk_sock_destruct(struct sock *sk)
> @@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
>
> priv = j1939_netdev_start(ndev);
> dev_put(ndev);
> +
> if (IS_ERR(priv)) {
> ret = PTR_ERR(priv);
> goto out_release_sock;
> @@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
> }
>
> /* spread RX notifications to all sockets subscribed to this session */
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> if (j1939_sk_recv_match_one(jsk, &session->skcb))
> __j1939_sk_errqueue(session, &jsk->sk, type);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> };
>
> void j1939_sk_send_loop_abort(struct sock *sk, int err)
> @@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
> struct j1939_sock *jsk;
> int error_code = ENETDOWN;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> jsk->sk.sk_err = error_code;
> if (!sock_flag(&jsk->sk, SOCK_DEAD))
> @@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
>
> j1939_sk_queue_drop_all(priv, jsk, error_code);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
> --
> 2.34.1
>
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
@ 2023-08-07 4:46 ` Oleksij Rempel
-1 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-08-07 4:46 UTC (permalink / raw)
To: Ziqi Zhao
Cc: davem, edumazet, ivan.orlov0322, kernel, kuba, linux, linux-can,
mkl, pabeni, robin, skhan, socketcan, arnd, netdev, bridge,
syzkaller-bugs, linux-kernel, mudongliangabcd, nikolay,
syzbot+1591462f226d9cbf0564, roopa, syzbot+881d65229ca4f9ae8c84
On Fri, Jul 21, 2023 at 09:22:26AM -0700, Ziqi Zhao wrote:
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Thank you!
> ---
> net/can/j1939/j1939-priv.h | 2 +-
> net/can/j1939/main.c | 2 +-
> net/can/j1939/socket.c | 25 +++++++++++++------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 16af1a7f80f6..74f15592d170 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -86,7 +86,7 @@ struct j1939_priv {
> unsigned int tp_max_packet_size;
>
> /* lock for j1939_socks list */
> - spinlock_t j1939_socks_lock;
> + rwlock_t j1939_socks_lock;
> struct list_head j1939_socks;
>
> struct kref rx_kref;
> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> index ecff1c947d68..a6fb89fa6278 100644
> --- a/net/can/j1939/main.c
> +++ b/net/can/j1939/main.c
> @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
> return ERR_PTR(-ENOMEM);
>
> j1939_tp_init(priv);
> - spin_lock_init(&priv->j1939_socks_lock);
> + rwlock_init(&priv->j1939_socks_lock);
> INIT_LIST_HEAD(&priv->j1939_socks);
>
> mutex_lock(&j1939_netdev_lock);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index feaec4ad6d16..a8b981dc2065 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
> jsk->state |= J1939_SOCK_BOUND;
> j1939_priv_get(priv);
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_add_tail(&jsk->list, &priv->j1939_socks);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
> {
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_del_init(&jsk->list);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
>
> j1939_priv_put(priv);
> jsk->state &= ~J1939_SOCK_BOUND;
> @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
> struct j1939_sock *jsk;
> bool match = false;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> match = j1939_sk_recv_match_one(jsk, skcb);
> if (match)
> break;
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
>
> return match;
> }
> @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
> {
> struct j1939_sock *jsk;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> j1939_sk_recv_one(jsk, skb);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_sk_sock_destruct(struct sock *sk)
> @@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
>
> priv = j1939_netdev_start(ndev);
> dev_put(ndev);
> +
> if (IS_ERR(priv)) {
> ret = PTR_ERR(priv);
> goto out_release_sock;
> @@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
> }
>
> /* spread RX notifications to all sockets subscribed to this session */
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> if (j1939_sk_recv_match_one(jsk, &session->skcb))
> __j1939_sk_errqueue(session, &jsk->sk, type);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> };
>
> void j1939_sk_send_loop_abort(struct sock *sk, int err)
> @@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
> struct j1939_sock *jsk;
> int error_code = ENETDOWN;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> jsk->sk.sk_err = error_code;
> if (!sock_flag(&jsk->sk, SOCK_DEAD))
> @@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
>
> j1939_sk_queue_drop_all(priv, jsk, error_code);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
> --
> 2.34.1
>
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [Bridge] [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
@ 2023-08-07 4:46 ` Oleksij Rempel
0 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-08-07 4:46 UTC (permalink / raw)
To: Ziqi Zhao
Cc: ivan.orlov0322, edumazet, syzbot+881d65229ca4f9ae8c84, socketcan,
bridge, nikolay, syzbot+1591462f226d9cbf0564, roopa, kuba,
pabeni, arnd, syzkaller-bugs, mudongliangabcd, linux-can, mkl,
skhan, robin, linux-kernel, linux, kernel, netdev, davem
On Fri, Jul 21, 2023 at 09:22:26AM -0700, Ziqi Zhao wrote:
> The following 3 locks would race against each other, causing the
> deadlock situation in the Syzbot bug report:
>
> - j1939_socks_lock
> - active_session_list_lock
> - sk_session_queue_lock
>
> A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> the rare situations where a write lock is required for the linked list
> that j1939_socks_lock is protecting, the code does not attempt to
> acquire any more locks. This would break the circular lock dependency,
> where, for example, the current thread already locks j1939_socks_lock
> and attempts to acquire sk_session_queue_lock, and at the same time,
> another thread attempts to acquire j1939_socks_lock while holding
> sk_session_queue_lock.
>
> NOTE: This patch along does not fix the unregister_netdevice bug
> reported by Syzbot; instead, it solves a deadlock situation to prepare
> for one or more further patches to actually fix the Syzbot bug, which
> appears to be a reference counting problem within the j1939 codebase.
>
> Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
> Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Thank you!
> ---
> net/can/j1939/j1939-priv.h | 2 +-
> net/can/j1939/main.c | 2 +-
> net/can/j1939/socket.c | 25 +++++++++++++------------
> 3 files changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 16af1a7f80f6..74f15592d170 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -86,7 +86,7 @@ struct j1939_priv {
> unsigned int tp_max_packet_size;
>
> /* lock for j1939_socks list */
> - spinlock_t j1939_socks_lock;
> + rwlock_t j1939_socks_lock;
> struct list_head j1939_socks;
>
> struct kref rx_kref;
> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> index ecff1c947d68..a6fb89fa6278 100644
> --- a/net/can/j1939/main.c
> +++ b/net/can/j1939/main.c
> @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
> return ERR_PTR(-ENOMEM);
>
> j1939_tp_init(priv);
> - spin_lock_init(&priv->j1939_socks_lock);
> + rwlock_init(&priv->j1939_socks_lock);
> INIT_LIST_HEAD(&priv->j1939_socks);
>
> mutex_lock(&j1939_netdev_lock);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index feaec4ad6d16..a8b981dc2065 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk)
> jsk->state |= J1939_SOCK_BOUND;
> j1939_priv_get(priv);
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_add_tail(&jsk->list, &priv->j1939_socks);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk)
> {
> - spin_lock_bh(&priv->j1939_socks_lock);
> + write_lock_bh(&priv->j1939_socks_lock);
> list_del_init(&jsk->list);
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + write_unlock_bh(&priv->j1939_socks_lock);
>
> j1939_priv_put(priv);
> jsk->state &= ~J1939_SOCK_BOUND;
> @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb)
> struct j1939_sock *jsk;
> bool match = false;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> match = j1939_sk_recv_match_one(jsk, skcb);
> if (match)
> break;
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
>
> return match;
> }
> @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb)
> {
> struct j1939_sock *jsk;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> j1939_sk_recv_one(jsk, skb);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static void j1939_sk_sock_destruct(struct sock *sk)
> @@ -484,6 +484,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len)
>
> priv = j1939_netdev_start(ndev);
> dev_put(ndev);
> +
> if (IS_ERR(priv)) {
> ret = PTR_ERR(priv);
> goto out_release_sock;
> @@ -1078,12 +1079,12 @@ void j1939_sk_errqueue(struct j1939_session *session,
> }
>
> /* spread RX notifications to all sockets subscribed to this session */
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> if (j1939_sk_recv_match_one(jsk, &session->skcb))
> __j1939_sk_errqueue(session, &jsk->sk, type);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> };
>
> void j1939_sk_send_loop_abort(struct sock *sk, int err)
> @@ -1271,7 +1272,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
> struct j1939_sock *jsk;
> int error_code = ENETDOWN;
>
> - spin_lock_bh(&priv->j1939_socks_lock);
> + read_lock_bh(&priv->j1939_socks_lock);
> list_for_each_entry(jsk, &priv->j1939_socks, list) {
> jsk->sk.sk_err = error_code;
> if (!sock_flag(&jsk->sk, SOCK_DEAD))
> @@ -1279,7 +1280,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv)
>
> j1939_sk_queue_drop_all(priv, jsk, error_code);
> }
> - spin_unlock_bh(&priv->j1939_socks_lock);
> + read_unlock_bh(&priv->j1939_socks_lock);
> }
>
> static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd,
> --
> 2.34.1
>
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
2023-07-04 6:19 [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
2023-07-10 17:53 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
@ 2023-11-15 3:54 ` syzbot
2 siblings, 0 replies; 18+ messages in thread
From: syzbot @ 2023-11-15 3:54 UTC (permalink / raw)
To: arnd, astrajoan, bridge, davem, dvyukov, edumazet, hdanton,
ivan.orlov0322, kernel, kuba, linux-can, linux-kernel, linux,
mkl, mudongliangabcd, netdev, nikolay, o.rempel, pabeni, robin,
roopa, skhan, socketcan, stephen, syzkaller-bugs, syzkaller
syzbot has bisected this issue to:
commit 2030043e616cab40f510299f09b636285e0a3678
Author: Oleksij Rempel <o.rempel@pengutronix.de>
Date: Fri May 21 11:57:20 2021 +0000
can: j1939: fix Use-after-Free, hold skb ref while in use
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1438c947680000
start commit: 1b907d050735 Merge tag '6.7-rc-smb3-client-fixes-part2' of..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=1638c947680000
console output: https://syzkaller.appspot.com/x/log.txt?x=1238c947680000
kernel config: https://syzkaller.appspot.com/x/.config?x=88e7ba51eecd9cd6
dashboard link: https://syzkaller.appspot.com/bug?extid=1591462f226d9cbf0564
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17fea8fb680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1633dc70e80000
Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
Fixes: 2030043e616c ("can: j1939: fix Use-after-Free, hold skb ref while in use")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock
2023-08-07 4:46 ` [Bridge] " Oleksij Rempel
(?)
@ 2023-11-17 8:10 ` Oleksij Rempel
-1 siblings, 0 replies; 18+ messages in thread
From: Oleksij Rempel @ 2023-11-17 8:10 UTC (permalink / raw)
To: Ziqi Zhao
Cc: ivan.orlov0322, edumazet, syzbot+881d65229ca4f9ae8c84, socketcan,
bridge, nikolay, syzbot+1591462f226d9cbf0564, roopa, kuba,
pabeni, arnd, syzkaller-bugs, mudongliangabcd, linux-can, mkl,
skhan, robin, linux-kernel, linux, kernel, netdev, davem
On Mon, Aug 07, 2023 at 06:46:34AM +0200, Oleksij Rempel wrote:
> On Fri, Jul 21, 2023 at 09:22:26AM -0700, Ziqi Zhao wrote:
> > The following 3 locks would race against each other, causing the
> > deadlock situation in the Syzbot bug report:
> >
> > - j1939_socks_lock
> > - active_session_list_lock
> > - sk_session_queue_lock
> >
> > A reasonable fix is to change j1939_socks_lock to an rwlock, since in
> > the rare situations where a write lock is required for the linked list
> > that j1939_socks_lock is protecting, the code does not attempt to
> > acquire any more locks. This would break the circular lock dependency,
> > where, for example, the current thread already locks j1939_socks_lock
> > and attempts to acquire sk_session_queue_lock, and at the same time,
> > another thread attempts to acquire j1939_socks_lock while holding
> > sk_session_queue_lock.
> >
> > NOTE: This patch along does not fix the unregister_netdevice bug
> > reported by Syzbot; instead, it solves a deadlock situation to prepare
> > for one or more further patches to actually fix the Syzbot bug, which
> > appears to be a reference counting problem within the j1939 codebase.
> >
> > Reported-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
> > Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
[not found] <20230711131958.334-1-hdanton@sina.com>
2023-07-11 13:20 ` syzbot
@ 2023-07-11 13:47 ` syzbot
1 sibling, 0 replies; 18+ messages in thread
From: syzbot @ 2023-07-11 13:47 UTC (permalink / raw)
To: hdanton, linux-kernel, syzkaller-bugs, syzkaller
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com
Tested on:
commit: e40939bb Merge branch 'for-next/core' into for-kernelci
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12a24702a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c84f463eb74eab24
dashboard link: https://syzkaller.appspot.com/bug?extid=1591462f226d9cbf0564
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
patch: https://syzkaller.appspot.com/x/patch.diff?x=1772e474a80000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2)
[not found] <20230711131958.334-1-hdanton@sina.com>
@ 2023-07-11 13:20 ` syzbot
2023-07-11 13:47 ` syzbot
1 sibling, 0 replies; 18+ messages in thread
From: syzbot @ 2023-07-11 13:20 UTC (permalink / raw)
To: hdanton; +Cc: hdanton, linux-kernel, syzkaller, syzkaller-bugs
> On Mon, 10 Jul 2023 10:53:57 -0700
>> HEAD commit: e40939bbfc68 Merge branch 'for-next/core' into for-kernelci
>> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=178f78d4a80000
>
> Put session without the session list lock held.
>
> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git e40939bbfc68
Your commands are accepted, but please keep syzkaller-bugs@googlegroups.com mailing list in CC next time. It serves as a history of what happened with each bug report. Thank you.
>
> --- x/net/can/j1939/transport.c
> +++ y/net/can/j1939/transport.c
> @@ -1083,7 +1083,6 @@ static bool j1939_session_deactivate_loc
>
> list_del_init(&session->active_session_list_entry);
> session->state = J1939_SESSION_DONE;
> - j1939_session_put(session);
> }
>
> return active;
> @@ -1098,6 +1097,9 @@ static bool j1939_session_deactivate(str
> active = j1939_session_deactivate_locked(session);
> j1939_session_list_unlock(priv);
>
> + if (active)
> + j1939_session_put(session);
> +
> return active;
> }
>
> @@ -2178,6 +2180,7 @@ void j1939_simple_recv(struct j1939_priv
> int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk)
> {
> struct j1939_session *session, *saved;
> + LIST_HEAD(active);
>
> netdev_dbg(priv->ndev, "%s, sk: %p\n", __func__, sk);
> j1939_session_list_lock(priv);
> @@ -2191,10 +2194,16 @@ int j1939_cancel_active_session(struct j
> j1939_session_put(session);
>
> session->err = ESHUTDOWN;
> - j1939_session_deactivate_locked(session);
> + if (j1939_session_deactivate_locked(session))
> + list_move(&session->active_session_list_entry, &active);
> }
> }
> j1939_session_list_unlock(priv);
> +
> + list_for_each_entry_safe(session, saved, &active, active_session_list_entry) {
> + list_del_init(&session->active_session_list_entry);
> + j1939_session_put(session);
> + }
> return NOTIFY_DONE;
> }
>
> --
^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2023-11-17 8:26 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
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2023-07-04 6:19 [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-04 6:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
2023-07-04 6:47 ` syzbot
2023-07-04 7:37 ` Oleksij Rempel
2023-07-21 16:22 ` Ziqi Zhao
2023-07-21 16:22 ` [Bridge] " Ziqi Zhao
2023-07-23 15:41 ` Oleksij Rempel
2023-07-23 15:41 ` [Bridge] " Oleksij Rempel
2023-08-07 4:46 ` Oleksij Rempel
2023-08-07 4:46 ` [Bridge] " Oleksij Rempel
2023-11-17 8:10 ` Oleksij Rempel
2023-07-10 17:53 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-12 0:47 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Ziqi Zhao
2023-07-12 1:16 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
2023-07-13 22:23 ` [PATCH] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock Stephen Hemminger
2023-11-15 3:54 ` [syzbot] [can?] possible deadlock in j1939_sk_errqueue (2) syzbot
[not found] <20230711131958.334-1-hdanton@sina.com>
2023-07-11 13:20 ` syzbot
2023-07-11 13:47 ` syzbot
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