From: syzbot <syzbot+ccdfb85a561b973219c7@syzkaller.appspotmail.com>
To: davem@davemloft.net, edumazet@google.com, horms@kernel.org,
kuba@kernel.org, linux-hams@vger.kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
pabeni@redhat.com, ralf@linux-mips.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [hams?] possible deadlock in nr_rt_device_down (3)
Date: Mon, 10 Feb 2025 18:23:27 -0800 [thread overview]
Message-ID: <67aab49f.050a0220.110943.0038.GAE@google.com> (raw)
In-Reply-To: <0000000000001abfb506221890b2@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 34c84b394890 Merge branch 'netconsole-cpu-population'
git tree: net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10a4fb18580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1909f2f0d8e641ce
dashboard link: https://syzkaller.appspot.com/bug?extid=ccdfb85a561b973219c7
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15d372a4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14e8c3f8580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a387ecc01ea6/disk-34c84b39.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/25869f4f9e04/vmlinux-34c84b39.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bfdfecda0154/bzImage-34c84b39.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ccdfb85a561b973219c7@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc1-syzkaller-00206-g34c84b394890 #0 Not tainted
------------------------------------------------------
syz-executor309/5900 is trying to acquire lock:
ffffffff8fe14a38 (nr_node_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffffffff8fe14a38 (nr_node_list_lock){+...}-{3:3}, at: nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517
but task is already holding lock:
ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x7b0 net/netrom/nr_route.c:514
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (nr_neigh_list_lock){+...}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_remove_neigh net/netrom/nr_route.c:307 [inline]
nr_dec_obs net/netrom/nr_route.c:472 [inline]
nr_rt_ioctl+0x398/0xfb0 net/netrom/nr_route.c:692
sock_do_ioctl+0x158/0x460 net/socket.c:1194
sock_ioctl+0x626/0x8e0 net/socket.c:1313
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
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
-> #1 (&nr_node->node_lock){+...}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_node_lock include/net/netrom.h:152 [inline]
nr_dec_obs net/netrom/nr_route.c:459 [inline]
nr_rt_ioctl+0x192/0xfb0 net/netrom/nr_route.c:692
sock_do_ioctl+0x158/0x460 net/socket.c:1194
sock_ioctl+0x626/0x8e0 net/socket.c:1313
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
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
-> #0 (nr_node_list_lock){+...}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3163 [inline]
check_prevs_add kernel/locking/lockdep.c:3282 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517
nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126
notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
__dev_notify_flags+0x207/0x400
dev_change_flags+0xf0/0x1a0 net/core/dev.c:9257
dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:563
dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826
sock_do_ioctl+0x240/0x460 net/socket.c:1208
sock_ioctl+0x626/0x8e0 net/socket.c:1313
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
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
other info that might help us debug this:
Chain exists of:
nr_node_list_lock --> &nr_node->node_lock --> nr_neigh_list_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(nr_neigh_list_lock);
lock(&nr_node->node_lock);
lock(nr_neigh_list_lock);
lock(nr_node_list_lock);
*** DEADLOCK ***
2 locks held by syz-executor309/5900:
#0: ffffffff8fcc0108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8fcc0108 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x706/0x1340 net/core/dev_ioctl.c:825
#1: ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#1: ffffffff8fe149d8 (nr_neigh_list_lock){+...}-{3:3}, at: nr_rt_device_down+0x28/0x7b0 net/netrom/nr_route.c:514
stack backtrace:
CPU: 1 UID: 0 PID: 5900 Comm: syz-executor309 Not tainted 6.14.0-rc1-syzkaller-00206-g34c84b394890 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
check_prev_add kernel/locking/lockdep.c:3163 [inline]
check_prevs_add kernel/locking/lockdep.c:3282 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_rt_device_down+0xb5/0x7b0 net/netrom/nr_route.c:517
nr_device_event+0x134/0x150 net/netrom/af_netrom.c:126
notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
__dev_notify_flags+0x207/0x400
dev_change_flags+0xf0/0x1a0 net/core/dev.c:9257
dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:563
dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:826
sock_do_ioctl+0x240/0x460 net/socket.c:1208
sock_ioctl+0x626/0x8e0 net/socket.c:1313
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
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: 0033:0x7f052c137829
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 1a 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:00007ffcc38957c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f052c137829
RDX: 0000400000000000 RSI: 0000000000008914 RDI: 0000000000000007
RBP: 0000000000000000 R08: 00007f052c185214 R09: 00007f052c185214
R10: fffffffffffffe1d R11: 0000000000000246 R12: 00007f052c1854a8
R13: 00007f052c185084 R14: 00007ffcc3895800 R15: 0000000000000000
</TASK>
---
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.
next prev parent reply other threads:[~2025-02-11 2:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-14 18:32 [syzbot] [hams?] possible deadlock in nr_rt_device_down (3) syzbot
2024-12-26 5:34 ` syzbot
2025-02-11 2:23 ` syzbot [this message]
[not found] <20250610080907.998-1-hdanton@sina.com>
2025-06-10 8:29 ` syzbot
[not found] <20250610085513.1045-1-hdanton@sina.com>
2025-06-10 9:15 ` syzbot
[not found] <20250610124453.1064-1-hdanton@sina.com>
2025-06-10 13:09 ` syzbot
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