* [syzbot] WARNING: refcount bug in nldev_newlink
@ 2022-12-07 20:51 syzbot
2022-12-08 9:14 ` Leon Romanovsky
0 siblings, 1 reply; 8+ messages in thread
From: syzbot @ 2022-12-07 20:51 UTC (permalink / raw)
To: jgg, leon, linux-kernel, linux-rdma, markzhang, ohartoov, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 591cd61541b9 Add linux-next specific files for 20221207
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11aeafad880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112536fb880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aa2e6d880000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bc862c01ec56/disk-591cd615.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f9b93f8ed2f/vmlinux-591cd615.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9d5cb636d548/bzImage-591cd615.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3fd8326d9a0812d19218@syzkaller.appspotmail.com
WARNING: CPU: 0 PID: 5156 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 5156 Comm: syz-executor773 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
RSP: 0018:ffffc90003ebf0d8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88802bfcba80 RSI: ffffffff8166b1dc RDI: fffff520007d7e0d
RBP: ffff888070296600 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff920007d7e20
R13: 0000000000000000 R14: ffff888070296600 R15: ffffc90003ebf608
FS: 000055555600f300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffed185b004 CR3: 00000000265db000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__refcount_dec include/linux/refcount.h:344 [inline]
refcount_dec include/linux/refcount.h:359 [inline]
ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
netdev_tracker_free include/linux/netdevice.h:4039 [inline]
netdev_put include/linux/netdevice.h:4056 [inline]
dev_put include/linux/netdevice.h:4082 [inline]
nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xd3/0x120 net/socket.c:734
____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
__sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
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: 0033:0x7fd5bc473699
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
</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.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
2022-12-07 20:51 [syzbot] WARNING: refcount bug in nldev_newlink syzbot
@ 2022-12-08 9:14 ` Leon Romanovsky
2022-12-08 11:42 ` Guoqing Jiang
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Leon Romanovsky @ 2022-12-08 9:14 UTC (permalink / raw)
To: syzbot, jgg; +Cc: linux-kernel, linux-rdma, markzhang, ohartoov, syzkaller-bugs
On Wed, Dec 07, 2022 at 12:51:39PM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 591cd61541b9 Add linux-next specific files for 20221207
> git tree: linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11aeafad880000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
> dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112536fb880000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aa2e6d880000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/bc862c01ec56/disk-591cd615.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/8f9b93f8ed2f/vmlinux-591cd615.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/9d5cb636d548/bzImage-591cd615.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3fd8326d9a0812d19218@syzkaller.appspotmail.com
>
> WARNING: CPU: 0 PID: 5156 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
> Modules linked in:
> CPU: 0 PID: 5156 Comm: syz-executor773 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
> RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
> Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
> RSP: 0018:ffffc90003ebf0d8 EFLAGS: 00010286
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: ffff88802bfcba80 RSI: ffffffff8166b1dc RDI: fffff520007d7e0d
> RBP: ffff888070296600 R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff920007d7e20
> R13: 0000000000000000 R14: ffff888070296600 R15: ffffc90003ebf608
> FS: 000055555600f300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffed185b004 CR3: 00000000265db000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __refcount_dec include/linux/refcount.h:344 [inline]
> refcount_dec include/linux/refcount.h:359 [inline]
> ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
> netdev_tracker_free include/linux/netdevice.h:4039 [inline]
> netdev_put include/linux/netdevice.h:4056 [inline]
> dev_put include/linux/netdevice.h:4082 [inline]
> nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
> rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
> rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
> netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
> netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
> netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
> sock_sendmsg_nosec net/socket.c:714 [inline]
> sock_sendmsg+0xd3/0x120 net/socket.c:734
> ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
> __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
> 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: 0033:0x7fd5bc473699
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
> RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
> R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
> R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
> </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.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
Jason, what do you think?
diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index a981ac2f0975..982938c1dae3 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1730,7 +1730,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
#endif
err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
up_read(&link_ops_rwsem);
- dev_put(ndev);
+ if (err)
+ dev_put(ndev);
return err;
}
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
2022-12-08 9:14 ` Leon Romanovsky
@ 2022-12-08 11:42 ` Guoqing Jiang
2022-12-08 11:54 ` Leon Romanovsky
2022-12-09 13:01 ` Jason Gunthorpe
[not found] ` <20221209134229.1987-1-hdanton@sina.com>
2 siblings, 1 reply; 8+ messages in thread
From: Guoqing Jiang @ 2022-12-08 11:42 UTC (permalink / raw)
To: Leon Romanovsky, syzbot, jgg
Cc: linux-kernel, linux-rdma, markzhang, ohartoov, syzkaller-bugs
Hi,
On 12/8/22 5:14 PM, Leon Romanovsky wrote:
> On Wed, Dec 07, 2022 at 12:51:39PM -0800, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 591cd61541b9 Add linux-next specific files for 20221207
>> git tree: linux-next
>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11aeafad880000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
>> dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112536fb880000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aa2e6d880000
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/bc862c01ec56/disk-591cd615.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/8f9b93f8ed2f/vmlinux-591cd615.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/9d5cb636d548/bzImage-591cd615.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+3fd8326d9a0812d19218@syzkaller.appspotmail.com
>>
>> WARNING: CPU: 0 PID: 5156 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
>> Modules linked in:
>> CPU: 0 PID: 5156 Comm: syz-executor773 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
>> RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
>> Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
>> RSP: 0018:ffffc90003ebf0d8 EFLAGS: 00010286
>> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
>> RDX: ffff88802bfcba80 RSI: ffffffff8166b1dc RDI: fffff520007d7e0d
>> RBP: ffff888070296600 R08: 0000000000000005 R09: 0000000000000000
>> R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff920007d7e20
>> R13: 0000000000000000 R14: ffff888070296600 R15: ffffc90003ebf608
>> FS: 000055555600f300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007ffed185b004 CR3: 00000000265db000 CR4: 00000000003506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> __refcount_dec include/linux/refcount.h:344 [inline]
>> refcount_dec include/linux/refcount.h:359 [inline]
>> ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
>> netdev_tracker_free include/linux/netdevice.h:4039 [inline]
>> netdev_put include/linux/netdevice.h:4056 [inline]
>> dev_put include/linux/netdevice.h:4082 [inline]
>> nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
>> rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
>> rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
>> netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>> netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>> netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>> sock_sendmsg_nosec net/socket.c:714 [inline]
>> sock_sendmsg+0xd3/0x120 net/socket.c:734
>> ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
>> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
>> __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
>> 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: 0033:0x7fd5bc473699
>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
>> RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
>> RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
>> R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
>> R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
>> </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.
>> syzbot can test patches for this issue, for details see:
>> https://goo.gl/tpsmEJ#testing-patches
> Jason, what do you think?
>
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index a981ac2f0975..982938c1dae3 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -1730,7 +1730,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
> #endif
> err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
> up_read(&link_ops_rwsem);
> - dev_put(ndev);
> + if (err)
> + dev_put(ndev);
>
> return err;
> }
>
I guess the dev_put is paired with dev_hold in dev_get_by_name,
maybe it should be protected by ink_ops_rwsem, otherwise
siw_exit_module could call ib_unregister_driver -> free_netdevs
after rdma_link_unregister (which needs to hold link_ops_rwsem),
then seems it is possible that ndev is freed before nldev_newlink
calls dev_put.
diff --git a/drivers/infiniband/core/nldev.c
b/drivers/infiniband/core/nldev.c
index 12dc97067ed2..f49bc8ee46da 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1715,8 +1715,8 @@ static int nldev_newlink(struct sk_buff *skb,
struct nlmsghdr *nlh,
}
#endif
err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
- up_read(&link_ops_rwsem);
dev_put(ndev);
+ up_read(&link_ops_rwsem);
return err;
}
Thanks,
Guoqing
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
2022-12-08 11:42 ` Guoqing Jiang
@ 2022-12-08 11:54 ` Leon Romanovsky
2022-12-09 0:48 ` Guoqing Jiang
0 siblings, 1 reply; 8+ messages in thread
From: Leon Romanovsky @ 2022-12-08 11:54 UTC (permalink / raw)
To: Guoqing Jiang
Cc: syzbot, jgg, linux-kernel, linux-rdma, markzhang, ohartoov,
syzkaller-bugs
On Thu, Dec 08, 2022 at 07:42:18PM +0800, Guoqing Jiang wrote:
> Hi,
>
> On 12/8/22 5:14 PM, Leon Romanovsky wrote:
> > On Wed, Dec 07, 2022 at 12:51:39PM -0800, syzbot wrote:
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit: 591cd61541b9 Add linux-next specific files for 20221207
> > > git tree: linux-next
> > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=11aeafad880000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
> > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112536fb880000
> > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aa2e6d880000
> > >
> > > Downloadable assets:
> > > disk image: https://storage.googleapis.com/syzbot-assets/bc862c01ec56/disk-591cd615.raw.xz
> > > vmlinux: https://storage.googleapis.com/syzbot-assets/8f9b93f8ed2f/vmlinux-591cd615.xz
> > > kernel image: https://storage.googleapis.com/syzbot-assets/9d5cb636d548/bzImage-591cd615.xz
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: syzbot+3fd8326d9a0812d19218@syzkaller.appspotmail.com
> > >
> > > WARNING: CPU: 0 PID: 5156 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
> > > Modules linked in:
> > > CPU: 0 PID: 5156 Comm: syz-executor773 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
> > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
> > > RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
> > > Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
> > > RSP: 0018:ffffc90003ebf0d8 EFLAGS: 00010286
> > > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> > > RDX: ffff88802bfcba80 RSI: ffffffff8166b1dc RDI: fffff520007d7e0d
> > > RBP: ffff888070296600 R08: 0000000000000005 R09: 0000000000000000
> > > R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff920007d7e20
> > > R13: 0000000000000000 R14: ffff888070296600 R15: ffffc90003ebf608
> > > FS: 000055555600f300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 00007ffed185b004 CR3: 00000000265db000 CR4: 00000000003506f0
> > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > Call Trace:
> > > <TASK>
> > > __refcount_dec include/linux/refcount.h:344 [inline]
> > > refcount_dec include/linux/refcount.h:359 [inline]
> > > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
> > > netdev_tracker_free include/linux/netdevice.h:4039 [inline]
> > > netdev_put include/linux/netdevice.h:4056 [inline]
> > > dev_put include/linux/netdevice.h:4082 [inline]
> > > nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
> > > rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
> > > rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
> > > netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
> > > netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
> > > netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
> > > sock_sendmsg_nosec net/socket.c:714 [inline]
> > > sock_sendmsg+0xd3/0x120 net/socket.c:734
> > > ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
> > > ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
> > > __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
> > > 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: 0033:0x7fd5bc473699
> > > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
> > > RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> > > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
> > > RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
> > > RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
> > > R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
> > > R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
> > > </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.
> > > syzbot can test patches for this issue, for details see:
> > > https://goo.gl/tpsmEJ#testing-patches
> > Jason, what do you think?
> >
> > diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> > index a981ac2f0975..982938c1dae3 100644
> > --- a/drivers/infiniband/core/nldev.c
> > +++ b/drivers/infiniband/core/nldev.c
> > @@ -1730,7 +1730,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
> > #endif
> > err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
> > up_read(&link_ops_rwsem);
> > - dev_put(ndev);
> > + if (err)
> > + dev_put(ndev);
> > return err;
> > }
> >
>
> I guess the dev_put is paired with dev_hold in dev_get_by_name,
Yes, my concern is that call to ->delink() calls to dev_put
unconditionally in free_netdevs() and I didn't see who called
to dev_hold() except dev_get_by_name.
Thanks
> maybe it should be protected by ink_ops_rwsem, otherwise
> siw_exit_module could call ib_unregister_driver -> free_netdevs
> after rdma_link_unregister (which needs to hold link_ops_rwsem),
> then seems it is possible that ndev is freed before nldev_newlink
> calls dev_put.
>
> diff --git a/drivers/infiniband/core/nldev.c
> b/drivers/infiniband/core/nldev.c
> index 12dc97067ed2..f49bc8ee46da 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -1715,8 +1715,8 @@ static int nldev_newlink(struct sk_buff *skb, struct
> nlmsghdr *nlh,
> }
> #endif
> err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
> - up_read(&link_ops_rwsem);
> dev_put(ndev);
> + up_read(&link_ops_rwsem);
>
> return err;
> }
>
> Thanks,
> Guoqing
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
2022-12-08 11:54 ` Leon Romanovsky
@ 2022-12-09 0:48 ` Guoqing Jiang
0 siblings, 0 replies; 8+ messages in thread
From: Guoqing Jiang @ 2022-12-09 0:48 UTC (permalink / raw)
To: Leon Romanovsky
Cc: syzbot, jgg, linux-kernel, linux-rdma, markzhang, ohartoov,
syzkaller-bugs
On 12/8/22 7:54 PM, Leon Romanovsky wrote:
> On Thu, Dec 08, 2022 at 07:42:18PM +0800, Guoqing Jiang wrote:
>> Hi,
>>
>> On 12/8/22 5:14 PM, Leon Romanovsky wrote:
>>> On Wed, Dec 07, 2022 at 12:51:39PM -0800, syzbot wrote:
>>>> Hello,
>>>>
>>>> syzbot found the following issue on:
>>>>
>>>> HEAD commit: 591cd61541b9 Add linux-next specific files for 20221207
>>>> git tree: linux-next
>>>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11aeafad880000
>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
>>>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112536fb880000
>>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aa2e6d880000
>>>>
>>>> Downloadable assets:
>>>> disk image: https://storage.googleapis.com/syzbot-assets/bc862c01ec56/disk-591cd615.raw.xz
>>>> vmlinux: https://storage.googleapis.com/syzbot-assets/8f9b93f8ed2f/vmlinux-591cd615.xz
>>>> kernel image: https://storage.googleapis.com/syzbot-assets/9d5cb636d548/bzImage-591cd615.xz
>>>>
>>>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>>>> Reported-by: syzbot+3fd8326d9a0812d19218@syzkaller.appspotmail.com
>>>>
>>>> WARNING: CPU: 0 PID: 5156 at lib/refcount.c:31 refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
>>>> Modules linked in:
>>>> CPU: 0 PID: 5156 Comm: syz-executor773 Not tainted 6.1.0-rc8-next-20221207-syzkaller #0
>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
>>>> RIP: 0010:refcount_warn_saturate+0x1d7/0x1f0 lib/refcount.c:31
>>>> Code: 05 5a 60 51 0a 01 e8 35 0a b5 05 0f 0b e9 d3 fe ff ff e8 6c 9b 75 fd 48 c7 c7 c0 6d a6 8a c6 05 37 60 51 0a 01 e8 16 0a b5 05 <0f> 0b e9 b4 fe ff ff 48 89 ef e8 5a b5 c3 fd e9 5c fe ff ff 0f 1f
>>>> RSP: 0018:ffffc90003ebf0d8 EFLAGS: 00010286
>>>> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
>>>> RDX: ffff88802bfcba80 RSI: ffffffff8166b1dc RDI: fffff520007d7e0d
>>>> RBP: ffff888070296600 R08: 0000000000000005 R09: 0000000000000000
>>>> R10: 0000000080000000 R11: 0000000000000000 R12: 1ffff920007d7e20
>>>> R13: 0000000000000000 R14: ffff888070296600 R15: ffffc90003ebf608
>>>> FS: 000055555600f300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
>>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>> CR2: 00007ffed185b004 CR3: 00000000265db000 CR4: 00000000003506f0
>>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>>> Call Trace:
>>>> <TASK>
>>>> __refcount_dec include/linux/refcount.h:344 [inline]
>>>> refcount_dec include/linux/refcount.h:359 [inline]
>>>> ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
>>>> netdev_tracker_free include/linux/netdevice.h:4039 [inline]
>>>> netdev_put include/linux/netdevice.h:4056 [inline]
>>>> dev_put include/linux/netdevice.h:4082 [inline]
>>>> nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
>>>> rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
>>>> rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
>>>> netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>>>> netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>>>> netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>>>> sock_sendmsg_nosec net/socket.c:714 [inline]
>>>> sock_sendmsg+0xd3/0x120 net/socket.c:734
>>>> ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
>>>> ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
>>>> __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
>>>> 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: 0033:0x7fd5bc473699
>>>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
>>>> RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>>>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
>>>> RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
>>>> RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
>>>> R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
>>>> R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
>>>> </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.
>>>> syzbot can test patches for this issue, for details see:
>>>> https://goo.gl/tpsmEJ#testing-patches
>>> Jason, what do you think?
>>>
>>> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
>>> index a981ac2f0975..982938c1dae3 100644
>>> --- a/drivers/infiniband/core/nldev.c
>>> +++ b/drivers/infiniband/core/nldev.c
>>> @@ -1730,7 +1730,8 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
>>> #endif
>>> err = ops ? ops->newlink(ibdev_name, ndev) : -EINVAL;
>>> up_read(&link_ops_rwsem);
>>> - dev_put(ndev);
>>> + if (err)
>>> + dev_put(ndev);
>>> return err;
>>> }
>>>
>> I guess the dev_put is paired with dev_hold in dev_get_by_name,
> Yes, my concern is that call to ->delink() calls to dev_put
> unconditionally in free_netdevs() and I didn't see who called
> to dev_hold() except dev_get_by_name.
My understanding is ops->newlink (either rxe_newlink or siw_newlink)
triggers dev_hold eventually which paired with dev_put in free_netdevs.
Thanks,
Guoqing
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
2022-12-08 9:14 ` Leon Romanovsky
2022-12-08 11:42 ` Guoqing Jiang
@ 2022-12-09 13:01 ` Jason Gunthorpe
[not found] ` <20221209134229.1987-1-hdanton@sina.com>
2 siblings, 0 replies; 8+ messages in thread
From: Jason Gunthorpe @ 2022-12-09 13:01 UTC (permalink / raw)
To: Leon Romanovsky
Cc: syzbot, linux-kernel, linux-rdma, markzhang, ohartoov, syzkaller-bugs
On Thu, Dec 08, 2022 at 11:14:39AM +0200, Leon Romanovsky wrote:
> > __refcount_dec include/linux/refcount.h:344 [inline]
> > refcount_dec include/linux/refcount.h:359 [inline]
> > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
> > netdev_tracker_free include/linux/netdevice.h:4039 [inline]
> > netdev_put include/linux/netdevice.h:4056 [inline]
> > dev_put include/linux/netdevice.h:4082 [inline]
> > nldev_newlink+0x360/0x5d0 drivers/infiniband/core/nldev.c:1733
> > rdma_nl_rcv_msg+0x371/0x6a0 drivers/infiniband/core/netlink.c:195
> > rdma_nl_rcv_skb.constprop.0.isra.0+0x2fc/0x440 drivers/infiniband/core/netlink.c:239
> > netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
> > netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
> > netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
> > sock_sendmsg_nosec net/socket.c:714 [inline]
> > sock_sendmsg+0xd3/0x120 net/socket.c:734
> > ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
> > ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
> > __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
> > 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: 0033:0x7fd5bc473699
> > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 c0 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007ffed185aff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd5bc473699
> > RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
> > RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
> > R10: 00007ffed185aa70 R11: 0000000000000246 R12: 00007ffed185b010
> > R13: 00000000000f4240 R14: 0000000000011fc1 R15: 00007ffed185b004
> > </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.
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
> Jason, what do you think?
No, the key to this report is that the refcount dec is inside the tracker:
> > __refcount_dec include/linux/refcount.h:344 [inline]
> > refcount_dec include/linux/refcount.h:359 [inline]
> > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
> > netdev_tracker_free include/linux/netdevice.h:4039 [inline]
Which is not underflowing the refcount on the dev, it is actually
trying to say the tracker has become unbalanced.
Eg this put is not matched with a hold that specified the tracker.
Probably this:
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index ff35cebb25e265..115b77c5e9a146 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2192,6 +2192,7 @@ static void free_netdevs(struct ib_device *ib_dev)
if (ndev) {
spin_lock(&ndev_hash_lock);
hash_del_rcu(&pdata->ndev_hash_link);
+ netdev_tracker_free(ndev, &pdata->netdev_tracker);
spin_unlock(&ndev_hash_lock);
/*
@@ -2201,7 +2202,7 @@ static void free_netdevs(struct ib_device *ib_dev)
* comparisons after the put
*/
rcu_assign_pointer(pdata->netdev, NULL);
- dev_put(ndev);
+ __dev_put(ndev);
}
spin_unlock_irqrestore(&pdata->netdev_lock, flags);
}
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
[not found] ` <20221209134229.1987-1-hdanton@sina.com>
@ 2022-12-09 14:06 ` Jason Gunthorpe
0 siblings, 0 replies; 8+ messages in thread
From: Jason Gunthorpe @ 2022-12-09 14:06 UTC (permalink / raw)
To: Hillf Danton
Cc: Leon Romanovsky, syzbot, linux-kernel, linux-rdma, markzhang,
ohartoov, syzkaller-bugs
On Fri, Dec 09, 2022 at 09:42:29PM +0800, Hillf Danton wrote:
> On 9 Dec 2022 09:01:14 -0400 Jason Gunthorpe <jgg@ziepe.ca>
> > On Thu, Dec 08, 2022 at 11:14:39AM +0200, Leon Romanovsky wrote:
> >
> > > Jason, what do you think?
> >
> > No, the key to this report is that the refcount dec is inside the tracker:
> >
> > > > __refcount_dec include/linux/refcount.h:344 [inline]
> > > > refcount_dec include/linux/refcount.h:359 [inline]
> > > > ref_tracker_free+0x539/0x6b0 lib/ref_tracker.c:118
> > > > netdev_tracker_free include/linux/netdevice.h:4039 [inline]
> >
> > Which is not underflowing the refcount on the dev, it is actually
> > trying to say the tracker has become unbalanced.
> >
> > Eg this put is not matched with a hold that specified the tracker.
> >
> > Probably this:
> >
> > diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> > index ff35cebb25e265..115b77c5e9a146 100644
> > --- a/drivers/infiniband/core/device.c
> > +++ b/drivers/infiniband/core/device.c
> > @@ -2192,6 +2192,7 @@ static void free_netdevs(struct ib_device *ib_dev)
> > if (ndev) {
> > spin_lock(&ndev_hash_lock);
> > hash_del_rcu(&pdata->ndev_hash_link);
> > + netdev_tracker_free(ndev, &pdata->netdev_tracker);
> > spin_unlock(&ndev_hash_lock);
> >
> > /*
> > @@ -2201,7 +2202,7 @@ static void free_netdevs(struct ib_device *ib_dev)
> > * comparisons after the put
> > */
> > rcu_assign_pointer(pdata->netdev, NULL);
> > - dev_put(ndev);
> > + __dev_put(ndev);
> > }
> > spin_unlock_irqrestore(&pdata->netdev_lock, flags);
> > }
>
> Wonder why this makes sense given rcu_assign_pointer(pdata->netdev, NULL)
> under pdata->netdev_lock.
Oh, yah, that is right, so we can just do the natural thing:
rcu_assign_pointer(pdata->netdev, NULL);
- dev_put(ndev);
+ netdev_put(ndev, &pdata->netdev_tracker);
Jason
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] WARNING: refcount bug in nldev_newlink
[not found] <20221211014342.2302-1-hdanton@sina.com>
@ 2022-12-11 10:42 ` syzbot
0 siblings, 0 replies; 8+ messages in thread
From: syzbot @ 2022-12-11 10:42 UTC (permalink / raw)
To: hdanton, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in corrupted
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { P5545 } 2629 jiffies s: 2809 root: 0x0/T
rcu: blocking rcu_node structures (internal RCU debug):
Tested on:
commit: 591cd615 Add linux-next specific files for 20221207
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13b5948f880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8b2d3e63e054c24f
dashboard link: https://syzkaller.appspot.com/bug?extid=3fd8326d9a0812d19218
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=1119320b880000
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-12-11 10:42 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-12-07 20:51 [syzbot] WARNING: refcount bug in nldev_newlink syzbot
2022-12-08 9:14 ` Leon Romanovsky
2022-12-08 11:42 ` Guoqing Jiang
2022-12-08 11:54 ` Leon Romanovsky
2022-12-09 0:48 ` Guoqing Jiang
2022-12-09 13:01 ` Jason Gunthorpe
[not found] ` <20221209134229.1987-1-hdanton@sina.com>
2022-12-09 14:06 ` Jason Gunthorpe
[not found] <20221211014342.2302-1-hdanton@sina.com>
2022-12-11 10:42 ` syzbot
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.