* [PATCH] Bluetooth: Use lock_sock() when acquiring lock in sco_conn_del
@ 2020-10-14 7:17 yanfei.xu
[not found] ` <20201014123113.21888-1-hdanton@sina.com>
0 siblings, 1 reply; 3+ messages in thread
From: yanfei.xu @ 2020-10-14 7:17 UTC (permalink / raw)
To: marcel, johan.hedberg, davem, kuba; +Cc: linux-bluetooth, netdev, linux-kernel
From: Yanfei Xu <yanfei.xu@windriver.com>
Locking slock-AF_BLUETOOTH-BTPROTO_SCO may happen in process context or
BH context. If in process context, we should use lock_sock(). As blow
warning, sco_conn_del() is called in process context, so let's use
lock_sock() instead of bh_lock_sock().
================================
WARNING: inconsistent lock state
5.9.0-rc4-syzkaller #0 Not tainted
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
syz-executor675/31233 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at:
spin_lock include/linux/spinlock.h:354 [inline]
ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at:
sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176
{IN-SOFTIRQ-W} state was registered at:
lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
sco_sock_timeout+0x24/0x140 net/bluetooth/sco.c:83
call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413
expire_timers kernel/time/timer.c:1458 [inline]
__run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755
__run_timers kernel/time/timer.c:1736 [inline]
run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768
__do_softirq+0x1f7/0xa91 kernel/softirq.c:298
asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
__run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77
invoke_softirq kernel/softirq.c:393 [inline]
__irq_exit_rcu kernel/softirq.c:423 [inline]
irq_exit_rcu+0x235/0x280 kernel/softirq.c:435
sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091
asm_sysvec_apic_timer_interrupt+0x12/0x20
arch/x86/include/asm/idtentry.h:581
unwind_next_frame+0x139a/0x1f90 arch/x86/kernel/unwind_orc.c:607
arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
slab_post_alloc_hook mm/slab.h:518 [inline]
slab_alloc mm/slab.c:3312 [inline]
kmem_cache_alloc+0x13a/0x3a0 mm/slab.c:3482
__d_alloc+0x2a/0x950 fs/dcache.c:1709
d_alloc+0x4a/0x230 fs/dcache.c:1788
d_alloc_parallel+0xe9/0x18e0 fs/dcache.c:2540
lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3030
open_last_lookups fs/namei.c:3177 [inline]
path_openat+0x96d/0x2730 fs/namei.c:3365
do_filp_open+0x17e/0x3c0 fs/namei.c:3395
do_sys_openat2+0x16d/0x420 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_open fs/open.c:1192 [inline]
__se_sys_open fs/open.c:1188 [inline]
__x64_sys_open+0x119/0x1c0 fs/open.c:1188
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
irq event stamp: 853
hardirqs last enabled at (853): [<ffffffff87f733af>]
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
hardirqs last enabled at (853): [<ffffffff87f733af>]
_raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199
hardirqs last disabled at (852): [<ffffffff87f73764>]
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:126 [inline]
hardirqs last disabled at (852): [<ffffffff87f73764>]
_raw_spin_lock_irq+0xa4/0xd0 kernel/locking/spinlock.c:167
softirqs last enabled at (0): [<ffffffff8144c929>]
copy_process+0x1a99/0x6920 kernel/fork.c:2018
softirqs last disabled at (0): [<0000000000000000>] 0x0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
<Interrupt>
lock(slock-AF_BLUETOOTH-BTPROTO_SCO);
*** DEADLOCK ***
3 locks held by syz-executor675/31233:
#0: ffff88809f104f40 (&hdev->req_lock){+.+.}-{3:3}, at:
hci_dev_do_close+0xf5/0x1080 net/bluetooth/hci_core.c:1720
#1: ffff88809f104078 (&hdev->lock){+.+.}-{3:3}, at:
hci_dev_do_close+0x253/0x1080 net/bluetooth/hci_core.c:1757
#2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_disconn_cfm include/net/bluetooth/hci_core.h:1435 [inline]
#2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_conn_hash_flush+0xc7/0x220 net/bluetooth/hci_conn.c:1557
stack backtrace:
CPU: 1 PID: 31233 Comm: syz-executor675 Not tainted 5.9.0-rc4-syzkaller
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118
print_usage_bug kernel/locking/lockdep.c:4020 [inline]
valid_state kernel/locking/lockdep.c:3361 [inline]
mark_lock_irq kernel/locking/lockdep.c:3560 [inline]
mark_lock.cold+0x7a/0x7f kernel/locking/lockdep.c:4006
mark_usage kernel/locking/lockdep.c:3923 [inline]
__lock_acquire+0x876/0x5570 kernel/locking/lockdep.c:4380
lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176
sco_disconn_cfm net/bluetooth/sco.c:1178 [inline]
sco_disconn_cfm+0x62/0x80 net/bluetooth/sco.c:1171
hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline]
hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557
hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770
hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790
vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
__fput+0x285/0x920 fs/file_table.c:281
task_work_run+0xdd/0x190 kernel/task_work.c:141
exit_task_work include/linux/task_work.h:25 [inline]
do_exit+0xb7d/0x29f0 kernel/exit.c:806
do_group_exit+0x125/0x310 kernel/exit.c:903
get_signal+0x428/0x1f00 kernel/signal.c:2757
arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:159 [inline]
exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190
syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x447279
Reported-by: syzbot+65684128cd7c35bc66a1@syzkaller.appspotmail.com
Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com>
---
net/bluetooth/sco.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index dcf7f96ff417..559b883c815f 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -173,10 +173,10 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
if (sk) {
sock_hold(sk);
- bh_lock_sock(sk);
+ lock_sock(sk);
sco_sock_clear_timer(sk);
sco_chan_del(sk, err);
- bh_unlock_sock(sk);
+ release_sock(sk);
sco_sock_kill(sk);
sock_put(sk);
}
--
2.18.2
^ permalink raw reply related [flat|nested] 3+ messages in thread[parent not found: <20201014123113.21888-1-hdanton@sina.com>]
* Re: [PATCH] Bluetooth: Use lock_sock() when acquiring lock in sco_conn_del [not found] ` <20201014123113.21888-1-hdanton@sina.com> @ 2020-10-16 3:15 ` Xu, Yanfei [not found] ` <20201016041028.601-1-hdanton@sina.com> 1 sibling, 0 replies; 3+ messages in thread From: Xu, Yanfei @ 2020-10-16 3:15 UTC (permalink / raw) To: Hillf Danton Cc: marcel, johan.hedberg, davem, kuba, linux-bluetooth, netdev, linux-kernel On 10/14/20 8:31 PM, Hillf Danton wrote: > > On Wed, 14 Oct 2020 15:17:31 +0800 >> From: Yanfei Xu <yanfei.xu@windriver.com> >> >> Locking slock-AF_BLUETOOTH-BTPROTO_SCO may happen in process context or >> BH context. If in process context, we should use lock_sock(). As blow >> warning, sco_conn_del() is called in process context, so let's use >> lock_sock() instead of bh_lock_sock(). >> > Sounds opposite because blocking BH in BH context provides no extra > protection while it makes sense in the less critical context particularly > wrt sock lock. > >> ================================ >> WARNING: inconsistent lock state >> 5.9.0-rc4-syzkaller #0 Not tainted >> -------------------------------- >> inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. >> syz-executor675/31233 [HC0[0]:SC0[0]:HE1:SE1] takes: >> ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: >> spin_lock include/linux/spinlock.h:354 [inline] >> ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: >> sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 >> {IN-SOFTIRQ-W} state was registered at: >> lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >> _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 >> spin_lock include/linux/spinlock.h:354 [inline] >> sco_sock_timeout+0x24/0x140 net/bluetooth/sco.c:83 >> call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 >> expire_timers kernel/time/timer.c:1458 [inline] >> __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 >> __run_timers kernel/time/timer.c:1736 [inline] >> run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 >> __do_softirq+0x1f7/0xa91 kernel/softirq.c:298 >> asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 >> __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] >> run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] >> do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 >> invoke_softirq kernel/softirq.c:393 [inline] >> __irq_exit_rcu kernel/softirq.c:423 [inline] >> irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 >> sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 >> asm_sysvec_apic_timer_interrupt+0x12/0x20 >> arch/x86/include/asm/idtentry.h:581 >> unwind_next_frame+0x139a/0x1f90 arch/x86/kernel/unwind_orc.c:607 >> arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 >> stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 >> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 >> kasan_set_track mm/kasan/common.c:56 [inline] >> __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 >> slab_post_alloc_hook mm/slab.h:518 [inline] >> slab_alloc mm/slab.c:3312 [inline] >> kmem_cache_alloc+0x13a/0x3a0 mm/slab.c:3482 >> __d_alloc+0x2a/0x950 fs/dcache.c:1709 >> d_alloc+0x4a/0x230 fs/dcache.c:1788 >> d_alloc_parallel+0xe9/0x18e0 fs/dcache.c:2540 >> lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3030 >> open_last_lookups fs/namei.c:3177 [inline] >> path_openat+0x96d/0x2730 fs/namei.c:3365 >> do_filp_open+0x17e/0x3c0 fs/namei.c:3395 >> do_sys_openat2+0x16d/0x420 fs/open.c:1168 >> do_sys_open fs/open.c:1184 [inline] >> __do_sys_open fs/open.c:1192 [inline] >> __se_sys_open fs/open.c:1188 [inline] >> __x64_sys_open+0x119/0x1c0 fs/open.c:1188 >> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 >> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> irq event stamp: 853 >> hardirqs last enabled at (853): [<ffffffff87f733af>] >> __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] >> hardirqs last enabled at (853): [<ffffffff87f733af>] >> _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 >> hardirqs last disabled at (852): [<ffffffff87f73764>] >> __raw_spin_lock_irq include/linux/spinlock_api_smp.h:126 [inline] >> hardirqs last disabled at (852): [<ffffffff87f73764>] >> _raw_spin_lock_irq+0xa4/0xd0 kernel/locking/spinlock.c:167 >> softirqs last enabled at (0): [<ffffffff8144c929>] >> copy_process+0x1a99/0x6920 kernel/fork.c:2018 >> softirqs last disabled at (0): [<0000000000000000>] 0x0 >> >> other info that might help us debug this: >> Possible unsafe locking scenario: >> >> CPU0 >> ---- >> lock(slock-AF_BLUETOOTH-BTPROTO_SCO); >> <Interrupt> >> lock(slock-AF_BLUETOOTH-BTPROTO_SCO); >> >> *** DEADLOCK *** >> >> 3 locks held by syz-executor675/31233: >> #0: ffff88809f104f40 (&hdev->req_lock){+.+.}-{3:3}, at: >> hci_dev_do_close+0xf5/0x1080 net/bluetooth/hci_core.c:1720 >> #1: ffff88809f104078 (&hdev->lock){+.+.}-{3:3}, at: >> hci_dev_do_close+0x253/0x1080 net/bluetooth/hci_core.c:1757 >> #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: >> hci_disconn_cfm include/net/bluetooth/hci_core.h:1435 [inline] >> #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: >> hci_conn_hash_flush+0xc7/0x220 net/bluetooth/hci_conn.c:1557 >> >> stack backtrace: >> CPU: 1 PID: 31233 Comm: syz-executor675 Not tainted 5.9.0-rc4-syzkaller >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x198/0x1fd lib/dump_stack.c:118 >> print_usage_bug kernel/locking/lockdep.c:4020 [inline] >> valid_state kernel/locking/lockdep.c:3361 [inline] >> mark_lock_irq kernel/locking/lockdep.c:3560 [inline] >> mark_lock.cold+0x7a/0x7f kernel/locking/lockdep.c:4006 >> mark_usage kernel/locking/lockdep.c:3923 [inline] >> __lock_acquire+0x876/0x5570 kernel/locking/lockdep.c:4380 >> lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >> _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 >> spin_lock include/linux/spinlock.h:354 [inline] >> sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 >> sco_disconn_cfm net/bluetooth/sco.c:1178 [inline] >> sco_disconn_cfm+0x62/0x80 net/bluetooth/sco.c:1171 >> hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline] >> hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557 >> hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770 >> hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790 >> vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340 >> __f put+0x285/0x920 fs/file_table.c:281 >> task_work_run+0xdd/0x190 kernel/task_work.c:141 >> exit_task_work include/linux/task_work.h:25 [inline] >> do_exit+0xb7d/0x29f0 kernel/exit.c:806 >> do_group_exit+0x125/0x310 kernel/exit.c:903 >> get_signal+0x428/0x1f00 kernel/signal.c:2757 >> arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 >> exit_to_user_mode_loop kernel/entry/common.c:159 [inline] >> exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190 >> syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 >> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> RIP: 0033:0x447279 >> >> Reported-by: syzbot+65684128cd7c35bc66a1@syzkaller.appspotmail.com >> Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com> >> --- >> net/bluetooth/sco.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c >> index dcf7f96ff417..559b883c815f 100644 >> --- a/net/bluetooth/sco.c >> +++ b/net/bluetooth/sco.c >> @@ -173,10 +173,10 @@ static void sco_conn_del(struct hci_conn *hcon, int err) >> >> if (sk) { >> sock_hold(sk); >> - bh_lock_sock(sk); >> + lock_sock(sk); >> sco_sock_clear_timer(sk); >> sco_chan_del(sk, err); >> - bh_unlock_sock(sk); >> + release_sock(sk); >> sco_sock_kill(sk); >> sock_put(sk); >> } >> -- >> 2.18.2 > > > --- a/net/bluetooth/sco.c > +++ b/net/bluetooth/sco.c > @@ -80,10 +80,10 @@ static void sco_sock_timeout(struct time > > BT_DBG("sock %p state %d", sk, sk->sk_state); > > - bh_lock_sock(sk); > + lock_sock(sk); > sk->sk_err = ETIMEDOUT; > sk->sk_state_change(sk); > - bh_unlock_sock(sk); > + unlock_sock(sk); > > sco_sock_kill(sk); > sock_put(sk); > Hi Hillf, Thanks for your reply! But I don't clearly understand what you mean. After your change, If sco_conn_del（） have got the lock and then run into sco_sock_timeout which is in BH, the potential deadlock is still exsit. As the function define, use bh_lock_sock in sco_sock_timeout(BH context) is right. The root cause is prevent from locking in BH after we've got the lock in sco_conn_del, isn't it? /* BH context may only use the following locking interface. */ #define bh_lock_sock(__sk) spin_lock(&((__sk)->sk_lock.slock)) Regards, Yanfei ^ permalink raw reply [flat|nested] 3+ messages in thread
[parent not found: <20201016041028.601-1-hdanton@sina.com>]
* Re: [PATCH] Bluetooth: Use lock_sock() when acquiring lock in sco_conn_del [not found] ` <20201016041028.601-1-hdanton@sina.com> @ 2020-10-19 1:54 ` Xu, Yanfei 0 siblings, 0 replies; 3+ messages in thread From: Xu, Yanfei @ 2020-10-19 1:54 UTC (permalink / raw) To: Hillf Danton Cc: marcel, johan.hedberg, davem, kuba, linux-bluetooth, netdev, linux-kernel On 10/16/20 12:10 PM, Hillf Danton wrote: > On Fri, 16 Oct 2020 11:15:27 +0800 Yanfei Xu wrote: >> On 10/14/20 8:31 PM, Hillf Danton wrote: >>> >>> On Wed, 14 Oct 2020 15:17:31 +0800 >>>> From: Yanfei Xu <yanfei.xu@windriver.com> >>>> >>>> Locking slock-AF_BLUETOOTH-BTPROTO_SCO may happen in process context or >>>> BH context. If in process context, we should use lock_sock(). As blow >>>> warning, sco_conn_del() is called in process context, so let's use >>>> lock_sock() instead of bh_lock_sock(). >>>> >>> Sounds opposite because blocking BH in BH context provides no extra >>> protection while it makes sense in the less critical context particularly >>> wrt sock lock. >>> >>>> ================================ >>>> WARNING: inconsistent lock state >>>> 5.9.0-rc4-syzkaller #0 Not tainted >>>> -------------------------------- >>>> inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. >>>> syz-executor675/31233 [HC0[0]:SC0[0]:HE1:SE1] takes: >>>> ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: >>>> spin_lock include/linux/spinlock.h:354 [inline] >>>> ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: >>>> sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 >>>> {IN-SOFTIRQ-W} state was registered at: >>>> lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 >>>> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >>>> _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 >>>> spin_lock include/linux/spinlock.h:354 [inline] >>>> sco_sock_timeout+0x24/0x140 net/bluetooth/sco.c:83 >>>> call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 >>>> expire_timers kernel/time/timer.c:1458 [inline] >>>> __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 >>>> __run_timers kernel/time/timer.c:1736 [inline] >>>> run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 >>>> __do_softirq+0x1f7/0xa91 kernel/softirq.c:298 >>>> asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 >>>> __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] >>>> run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] >>>> do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 >>>> invoke_softirq kernel/softirq.c:393 [inline] >>>> __irq_exit_rcu kernel/softirq.c:423 [inline] >>>> irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 >>>> sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 >>>> asm_sysvec_apic_timer_interrupt+0x12/0x20 >>>> arch/x86/include/asm/idtentry.h:581 >>>> unwind_next_frame+0x139a/0x1f90 arch/x86/kernel/unwind_orc.c:607 >>>> arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 >>>> stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 >>>> kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 >>>> kasan_set_track mm/kasan/common.c:56 [inline] >>>> __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 >>>> slab_post_alloc_hook mm/slab.h:518 [inline] >>>> slab_alloc mm/slab.c:3312 [inline] >>>> kmem_cache_alloc+0x13a/0x3a0 mm/slab.c:3482 >>>> __d_alloc+0x2a/0x950 fs/dcache.c:1709 >>>> d_alloc+0x4a/0x230 fs/dcache.c:1788 >>>> d_alloc_parallel+0xe9/0x18e0 fs/dcache.c:2540 >>>> lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3030 >>>> open_last_lookups fs/namei.c:3177 [inline] >>>> path_openat+0x96d/0x2730 fs/namei.c:3365 >>>> do_filp_open+0x17e/0x3c0 fs/namei.c:3395 >>>> do_sys_openat2+0x16d/0x420 fs/open.c:1168 >>>> do_sys_open fs/open.c:1184 [inline] >>>> __do_sys_open fs/open.c:1192 [inline] >>>> __se_sys_open fs/open.c:1188 [inline] >>>> __x64_sys_open+0x119/0x1c0 fs/open.c:1188 >>>> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 >>>> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>>> irq event stamp: 853 >>>> hardirqs last enabled at (853): [<ffffffff87f733af>] >>>> __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] >>>> hardirqs last enabled at (853): [<ffffffff87f733af>] >>>> _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 >>>> hardirqs last disabled at (852): [<ffffffff87f73764>] >>>> __raw_spin_lock_irq include/linux/spinlock_api_smp.h:126 [inline] >>>> hardirqs last disabled at (852): [<ffffffff87f73764>] >>>> _raw_spin_lock_irq+0xa4/0xd0 kernel/locking/spinlock.c:167 >>>> softirqs last enabled at (0): [<ffffffff8144c929>] >>>> copy_process+0x1a99/0x6920 kernel/fork.c:2018 >>>> softirqs last disabled at (0): [<0000000000000000>] 0x0 >>>> >>>> other info that might help us debug this: >>>> Possible unsafe locking scenario: >>>> >>>> CPU0 >>>> ---- >>>> lock(slock-AF_BLUETOOTH-BTPROTO_SCO); >>>> <Interrupt> >>>> lock(slock-AF_BLUETOOTH-BTPROTO_SCO); >>>> >>>> *** DEADLOCK *** >>>> >>>> 3 locks held by syz-executor675/31233: >>>> #0: ffff88809f104f40 (&hdev->req_lock){+.+.}-{3:3}, at: >>>> hci_dev_do_close+0xf5/0x1080 net/bluetooth/hci_core.c:1720 >>>> #1: ffff88809f104078 (&hdev->lock){+.+.}-{3:3}, at: >>>> hci_dev_do_close+0x253/0x1080 net/bluetooth/hci_core.c:1757 >>>> #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: >>>> hci_disconn_cfm include/net/bluetooth/hci_core.h:1435 [inline] >>>> #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: >>>> hci_conn_hash_flush+0xc7/0x220 net/bluetooth/hci_conn.c:1557 >>>> >>>> stack backtrace: >>>> CPU: 1 PID: 31233 Comm: syz-executor675 Not tainted 5.9.0-rc4-syzkaller >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>>> Google 01/01/2011 >>>> Call Trace: >>>> __dump_stack lib/dump_stack.c:77 [inline] >>>> dump_stack+0x198/0x1fd lib/dump_stack.c:118 >>>> print_usage_bug kernel/locking/lockdep.c:4020 [inline] >>>> valid_state kernel/locking/lockdep.c:3361 [inline] >>>> mark_lock_irq kernel/locking/lockdep.c:3560 [inline] >>>> mark_lock.cold+0x7a/0x7f kernel/locking/lockdep.c:4006 >>>> mark_usage kernel/locking/lockdep.c:3923 [inline] >>>> __lock_acquire+0x876/0x5570 kernel/locking/lockdep.c:4380 >>>> lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 >>>> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >>>> _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 >>>> spin_lock include/linux/spinlock.h:354 [inline] >>>> sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 >>>> sco_disconn_cfm net/bluetooth/sco.c:1178 [inline] >>>> sco_disconn_cfm+0x62/0x80 net/bluetooth/sco.c:1171 >>>> hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline] >>>> hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557 >>>> hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770 >>>> hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790 >>>> vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340 >>>> __f put+0x285/0x920 fs/file_table.c:281 >>>> task_work_run+0xdd/0x190 kernel/task_work.c:141 >>>> exit_task_work include/linux/task_work.h:25 [inline] >>>> do_exit+0xb7d/0x29f0 kernel/exit.c:806 >>>> do_group_exit+0x125/0x310 kernel/exit.c:903 >>>> get_signal+0x428/0x1f00 kernel/signal.c:2757 >>>> arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 >>>> exit_to_user_mode_loop kernel/entry/common.c:159 [inline] >>>> exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190 >>>> syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 >>>> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>>> RIP: 0033:0x447279 >>>> >>>> Reported-by: syzbot+65684128cd7c35bc66a1@syzkaller.appspotmail.com >>>> Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com> >>>> --- >>>> net/bluetooth/sco.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c >>>> index dcf7f96ff417..559b883c815f 100644 >>>> --- a/net/bluetooth/sco.c >>>> +++ b/net/bluetooth/sco.c >>>> @@ -173,10 +173,10 @@ static void sco_conn_del(struct hci_conn *hcon, int err) >>>> >>>> if (sk) { >>>> sock_hold(sk); >>>> - bh_lock_sock(sk); >>>> + lock_sock(sk); >>>> sco_sock_clear_timer(sk); >>>> sco_chan_del(sk, err); >>>> - bh_unlock_sock(sk); >>>> + release_sock(sk); >>>> sco_sock_kill(sk); >>>> sock_put(sk); >>>> } >>>> -- >>>> 2.18.2 >>> >>> >>> --- a/net/bluetooth/sco.c >>> +++ b/net/bluetooth/sco.c >>> @@ -80,10 +80,10 @@ static void sco_sock_timeout(struct time >>> >>> BT_DBG("sock %p state %d", sk, sk->sk_state); >>> >>> - bh_lock_sock(sk); >>> + lock_sock(sk); >>> sk->sk_err = ETIMEDOUT; >>> sk->sk_state_change(sk); >>> - bh_unlock_sock(sk); >>> + unlock_sock(sk); >>> >>> sco_sock_kill(sk); >>> sock_put(sk); >>> >> Hi Hillf, >> >> Thanks for your reply! But I don't clearly understand what you mean. >> >> After your change, If sco_conn_del（） have got the lock and then run into >> sco_sock_timeout which is in BH, the potential deadlock is still exsit. > > My change is incorrect. Thanks for your reply. > >> >> As the function define, use bh_lock_sock in sco_sock_timeout(BH context) >> is right. The root cause is prevent from locking in BH after we've got >> the lock in sco_conn_del, isn't it? >> >> /* BH context may only use the following locking interface. */ >> #define bh_lock_sock(__sk) spin_lock(&((__sk)->sk_lock.slock)) > > Then replacing bh_lock_sock() with lock_sock() in sco_conn_del() seems > not to work because bh is enabled after lock_sock(). What we want instead > is block bh here until we release sock, something like the diff below. > > --- a/net/bluetooth/sco.c > +++ b/net/bluetooth/sco.c > @@ -173,10 +173,12 @@ static void sco_conn_del(struct hci_conn > > if (sk) { > sock_hold(sk); > + local_bh_disable(); > bh_lock_sock(sk); > sco_sock_clear_timer(sk); > sco_chan_del(sk, err); > bh_unlock_sock(sk); > + local_bh_enable(); > sco_sock_kill(sk); > sock_put(sk); > } > Anyone else have any suggestion? :) Thanks, Yanfei ^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-10-14 7:17 [PATCH] Bluetooth: Use lock_sock() when acquiring lock in sco_conn_del yanfei.xu
[not found] ` <20201014123113.21888-1-hdanton@sina.com>
2020-10-16 3:15 ` Xu, Yanfei
[not found] ` <20201016041028.601-1-hdanton@sina.com>
2020-10-19 1:54 ` Xu, Yanfei
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