* [syzbot] [net?] possible deadlock in dev_set_allmulti
@ 2025-03-11 20:10 syzbot
2025-03-11 20:38 ` Stanislav Fomichev
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2025-03-11 20:10 UTC (permalink / raw)
To: davem, edumazet, horms, kuba, linux-kernel, netdev, pabeni,
syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 40587f749df2 Merge branch 'enic-enable-32-64-byte-cqes-and..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=128b1f8c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ca99d9d1f4a8ecfa
dashboard link: https://syzkaller.appspot.com/bug?extid=b0c03d76056ef6cd12a6
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6d02993a9211/disk-40587f74.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2c8b300bf362/vmlinux-40587f74.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2d5be21882cf/bzImage-40587f74.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b0c03d76056ef6cd12a6@syzkaller.appspotmail.com
netlink: 'syz.4.478': attribute type 10 has an invalid length.
netdevsim netdevsim4 netdevsim0: left allmulticast mode
============================================
WARNING: possible recursive locking detected
6.14.0-rc5-syzkaller-01183-g40587f749df2 #0 Not tainted
--------------------------------------------
syz.4.478/7361 is trying to acquire lock:
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_set_allmulti+0x11c/0x270 net/core/dev_api.c:279
but task is already holding lock:
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x11c/0x260 net/core/dev_api.c:190
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&dev->lock);
lock(&dev->lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by syz.4.478/7361:
#0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc4c/0x1d90 net/core/rtnetlink.c:4054
#1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
#1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
#1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x11c/0x260 net/core/dev_api.c:190
stack backtrace:
CPU: 1 UID: 0 PID: 7361 Comm: syz.4.478 Not tainted 6.14.0-rc5-syzkaller-01183-g40587f749df2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3039
check_deadlock kernel/locking/lockdep.c:3091 [inline]
validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3893
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
netdev_lock include/linux/netdevice.h:2731 [inline]
netdev_lock_ops include/net/netdev_lock.h:40 [inline]
dev_set_allmulti+0x11c/0x270 net/core/dev_api.c:279
vlan_dev_open+0x2be/0x8a0 net/8021q/vlan_dev.c:278
__dev_open+0x45a/0x8a0 net/core/dev.c:1644
__dev_change_flags+0x1e2/0x6f0 net/core/dev.c:9375
netif_change_flags+0x8b/0x1a0 net/core/dev.c:9438
dev_change_flags+0x146/0x270 net/core/dev_api.c:68
vlan_device_event+0x1b81/0x1de0 net/8021q/vlan.c:469
notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2244 [inline]
call_netdevice_notifiers net/core/dev.c:2258 [inline]
netif_open+0x13a/0x1b0 net/core/dev.c:1672
dev_open+0x13e/0x260 net/core/dev_api.c:191
bond_enslave+0x103c/0x3910 drivers/net/bonding/bond_main.c:2135
do_set_master+0x579/0x730 net/core/rtnetlink.c:2943
do_setlink+0xfee/0x40f0 net/core/rtnetlink.c:3149
rtnl_changelink net/core/rtnetlink.c:3759 [inline]
__rtnl_newlink net/core/rtnetlink.c:3918 [inline]
rtnl_newlink+0x15a6/0x1d90 net/core/rtnetlink.c:4055
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6945
netlink_rcv_skb+0x206/0x480 net/netlink/af_netlink.c:2534
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:709 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:724
____sys_sendmsg+0x53a/0x860 net/socket.c:2564
___sys_sendmsg net/socket.c:2618 [inline]
__sys_sendmsg+0x269/0x350 net/socket.c:2650
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f191f98d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f192081c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f191fba5fa0 RCX: 00007f191f98d169
RDX: 0000000000000000 RSI: 0000400000000680 RDI: 0000000000000003
RBP: 00007f191fa0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f191fba5fa0 R15: 00007ffc4fecad18
</TASK>
---
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [net?] possible deadlock in dev_set_allmulti
2025-03-11 20:10 [syzbot] [net?] possible deadlock in dev_set_allmulti syzbot
@ 2025-03-11 20:38 ` Stanislav Fomichev
0 siblings, 0 replies; 2+ messages in thread
From: Stanislav Fomichev @ 2025-03-11 20:38 UTC (permalink / raw)
To: syzbot
Cc: davem, edumazet, horms, kuba, linux-kernel, netdev, pabeni,
syzkaller-bugs
On 03/11, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 40587f749df2 Merge branch 'enic-enable-32-64-byte-cqes-and..
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=128b1f8c580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=ca99d9d1f4a8ecfa
> dashboard link: https://syzkaller.appspot.com/bug?extid=b0c03d76056ef6cd12a6
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/6d02993a9211/disk-40587f74.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/2c8b300bf362/vmlinux-40587f74.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/2d5be21882cf/bzImage-40587f74.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b0c03d76056ef6cd12a6@syzkaller.appspotmail.com
>
> netlink: 'syz.4.478': attribute type 10 has an invalid length.
> netdevsim netdevsim4 netdevsim0: left allmulticast mode
> ============================================
> WARNING: possible recursive locking detected
> 6.14.0-rc5-syzkaller-01183-g40587f749df2 #0 Not tainted
> --------------------------------------------
> syz.4.478/7361 is trying to acquire lock:
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_set_allmulti+0x11c/0x270 net/core/dev_api.c:279
>
> but task is already holding lock:
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
> ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x11c/0x260 net/core/dev_api.c:190
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&dev->lock);
> lock(&dev->lock);
>
> *** DEADLOCK ***
>
> May be due to missing lock nesting notation
>
> 2 locks held by syz.4.478/7361:
> #0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
> #0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
> #0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc4c/0x1d90 net/core/rtnetlink.c:4054
> #1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
> #1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
> #1: ffff88807b5e4d28 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x11c/0x260 net/core/dev_api.c:190
>
> stack backtrace:
> CPU: 1 UID: 0 PID: 7361 Comm: syz.4.478 Not tainted 6.14.0-rc5-syzkaller-01183-g40587f749df2 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3039
> check_deadlock kernel/locking/lockdep.c:3091 [inline]
> validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3893
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __mutex_lock_common kernel/locking/mutex.c:585 [inline]
> __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
> netdev_lock include/linux/netdevice.h:2731 [inline]
> netdev_lock_ops include/net/netdev_lock.h:40 [inline]
> dev_set_allmulti+0x11c/0x270 net/core/dev_api.c:279
> vlan_dev_open+0x2be/0x8a0 net/8021q/vlan_dev.c:278
> __dev_open+0x45a/0x8a0 net/core/dev.c:1644
> __dev_change_flags+0x1e2/0x6f0 net/core/dev.c:9375
> netif_change_flags+0x8b/0x1a0 net/core/dev.c:9438
> dev_change_flags+0x146/0x270 net/core/dev_api.c:68
> vlan_device_event+0x1b81/0x1de0 net/8021q/vlan.c:469
> notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
> call_netdevice_notifiers_extack net/core/dev.c:2244 [inline]
> call_netdevice_notifiers net/core/dev.c:2258 [inline]
> netif_open+0x13a/0x1b0 net/core/dev.c:1672
> dev_open+0x13e/0x260 net/core/dev_api.c:191
> bond_enslave+0x103c/0x3910 drivers/net/bonding/bond_main.c:2135
> do_set_master+0x579/0x730 net/core/rtnetlink.c:2943
> do_setlink+0xfee/0x40f0 net/core/rtnetlink.c:3149
> rtnl_changelink net/core/rtnetlink.c:3759 [inline]
> __rtnl_newlink net/core/rtnetlink.c:3918 [inline]
> rtnl_newlink+0x15a6/0x1d90 net/core/rtnetlink.c:4055
> rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6945
> netlink_rcv_skb+0x206/0x480 net/netlink/af_netlink.c:2534
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:709 [inline]
> __sock_sendmsg+0x221/0x270 net/socket.c:724
> ____sys_sendmsg+0x53a/0x860 net/socket.c:2564
> ___sys_sendmsg net/socket.c:2618 [inline]
> __sys_sendmsg+0x269/0x350 net/socket.c:2650
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f191f98d169
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f192081c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007f191fba5fa0 RCX: 00007f191f98d169
> RDX: 0000000000000000 RSI: 0000400000000680 RDI: 0000000000000003
> RBP: 00007f191fa0e2a0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f191fba5fa0 R15: 00007ffc4fecad18
> </TASK>
This one is bad :-( If I read the trace correctly, it's a vlan device
that's being added to a bonding device. In bond_enslave->dev_open,
we lock the vlan device and run the notifiers. And the vlan notifier
uses dev_xxx methods that try to lock the vlan device again.
I will try to repro locally tomorrow. We might have to release the
netdev locks during the notifier runs :-/
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-03-11 20:38 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
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2025-03-11 20:10 [syzbot] [net?] possible deadlock in dev_set_allmulti syzbot
2025-03-11 20:38 ` Stanislav Fomichev
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