Hello,
syzbot found the following issue on:
HEAD commit: b95c01af2113 Linux 5.15.152
git tree: linux-5.15.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=12844711180000
kernel config:
https://syzkaller.appspot.com/x/.config?x=b26cb65e5b8ad5c7
dashboard link:
https://syzkaller.appspot.com/bug?extid=9acd3e79e2d0385a2b8a
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/2fc98856fcae/disk-b95c01af.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/3186db0dfe08/vmlinux-b95c01af.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/0df136a3e808/bzImage-b95c01af.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+9acd3e...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
5.15.152-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/5979 is trying to acquire lock:
ffff888059f151c0 (&stab->lock){+.-.}-{2:2}, at: __sock_map_delete net/core/sock_map.c:416 [inline]
ffff888059f151c0 (&stab->lock){+.-.}-{2:2}, at: sock_map_delete_elem+0x97/0x130 net/core/sock_map.c:448
but task is already holding lock:
ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:147 [inline]
ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xcc/0x5d0 net/core/sock_map.c:182
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&psock->link_lock){+...}-{2:2}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:368 [inline]
sock_map_add_link net/core/sock_map.c:136 [inline]
sock_map_update_common+0x31c/0x5b0 net/core/sock_map.c:502
sock_map_update_elem_sys+0x440/0x770 net/core/sock_map.c:585
map_update_elem+0x6a0/0x7c0 kernel/bpf/syscall.c:1163
__sys_bpf+0x2fd/0x670 kernel/bpf/syscall.c:4617
__do_sys_bpf kernel/bpf/syscall.c:4733 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4731 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4731
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
-> #0 (&stab->lock){+.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
__sock_map_delete net/core/sock_map.c:416 [inline]
sock_map_delete_elem+0x97/0x130 net/core/sock_map.c:448
bpf_prog_330576d32f01b34b+0x5b/0x6e0
bpf_dispatcher_nop_func include/linux/bpf.h:780 [inline]
__bpf_prog_run include/linux/filter.h:625 [inline]
bpf_prog_run include/linux/filter.h:632 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1917
__bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:118
trace_kfree include/trace/events/kmem.h:118 [inline]
kfree+0x22f/0x270 mm/slub.c:4549
sk_psock_free_link include/linux/skmsg.h:422 [inline]
sock_map_del_link net/core/sock_map.c:160 [inline]
sock_map_unref+0x3ac/0x5d0 net/core/sock_map.c:182
sock_hash_update_common+0x911/0xa30 net/core/sock_map.c:1028
sock_map_update_elem_sys+0x485/0x770 net/core/sock_map.c:587
map_update_elem+0x6a0/0x7c0 kernel/bpf/syscall.c:1163
__sys_bpf+0x2fd/0x670 kernel/bpf/syscall.c:4617
__do_sys_bpf kernel/bpf/syscall.c:4733 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4731 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4731
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&psock->link_lock);
lock(&stab->lock);
lock(&psock->link_lock);
lock(&stab->lock);
*** DEADLOCK ***
5 locks held by syz-executor.4/5979:
#0: ffff88807b1c6120 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1668 [inline]
#0: ffff88807b1c6120 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_sk_acquire net/core/sock_map.c:119 [inline]
#0: ffff88807b1c6120 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_update_elem_sys+0x1c8/0x770 net/core/sock_map.c:581
#1: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:268
#2: ffff88805afc9c20 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1005
#3: ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
#3: ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:147 [inline]
#3: ffff88805d3fc290 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xcc/0x5d0 net/core/sock_map.c:182
#4: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:268
stack backtrace:
CPU: 1 PID: 5979 Comm: syz-executor.4 Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
__sock_map_delete net/core/sock_map.c:416 [inline]
sock_map_delete_elem+0x97/0x130 net/core/sock_map.c:448
bpf_prog_330576d32f01b34b+0x5b/0x6e0
bpf_dispatcher_nop_func include/linux/bpf.h:780 [inline]
__bpf_prog_run include/linux/filter.h:625 [inline]
bpf_prog_run include/linux/filter.h:632 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1917
__bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:118
trace_kfree include/trace/events/kmem.h:118 [inline]
kfree+0x22f/0x270 mm/slub.c:4549
sk_psock_free_link include/linux/skmsg.h:422 [inline]
sock_map_del_link net/core/sock_map.c:160 [inline]
sock_map_unref+0x3ac/0x5d0 net/core/sock_map.c:182
sock_hash_update_common+0x911/0xa30 net/core/sock_map.c:1028
sock_map_update_elem_sys+0x485/0x770 net/core/sock_map.c:587
map_update_elem+0x6a0/0x7c0 kernel/bpf/syscall.c:1163
__sys_bpf+0x2fd/0x670 kernel/bpf/syscall.c:4617
__do_sys_bpf kernel/bpf/syscall.c:4733 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4731 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4731
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f9c0cd51da9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9c0b2d20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f9c0ce7ff80 RCX: 00007f9c0cd51da9
RDX: 0000000000000020 RSI: 0000000020000040 RDI: 0000000000000002
RBP: 00007f9c0cd9e47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9c0ce7ff80 R15: 00007ffd08342f38
</TASK>
---
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