syzbot


possible deadlock in sock_map_update_common

Status: upstream: reported C repro on 2024/03/29 17:11
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+6c4a9954273658c1d222@syzkaller.appspotmail.com
First crash: 87d, last: 20d
Bug presence (1)
Date Name Commit Repro Result
2024/06/13 upstream (ToT) 2ccbdf43d5e7 C [report] SYZFAIL: NL802154_CMD_SET_SHORT_ADDR failed
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in sock_map_update_common (2) bpf net C done 12 16d 27d 0/27 upstream: reported C repro on 2024/05/28 10:24
linux-5.15 possible deadlock in sock_map_update_common origin:upstream missing-backport C done 12 8d23h 72d 0/3 upstream: reported C repro on 2024/04/13 07:12

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.1.90-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor404/3547 is trying to acquire lock:
ffff888021742290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888021742290 (&psock->link_lock){+...}-{2:2}, at: sock_map_add_link net/core/sock_map.c:136 [inline]
ffff888021742290 (&psock->link_lock){+...}-{2:2}, at: sock_map_update_common+0x31c/0x5b0 net/core/sock_map.c:505

but task is already holding lock:
ffff88807d8f8240 (&stab->lock){+...}-{2:2}, at: sock_map_update_common+0x1b6/0x5b0 net/core/sock_map.c:495

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&stab->lock){+...}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
       __sock_map_delete net/core/sock_map.c:419 [inline]
       sock_map_delete_elem+0x161/0x230 net/core/sock_map.c:451
       bpf_prog_330576d32f01b34b+0x5b/0x5f
       bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
       __bpf_prog_run include/linux/filter.h:603 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline]
       bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312
       __bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:94
       trace_kfree include/trace/events/kmem.h:94 [inline]
       kfree+0xf6/0x190 mm/slab_common.c:994
       sk_psock_free_link include/linux/skmsg.h:416 [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:1029
       sock_map_update_elem_sys+0x5a0/0x910 net/core/sock_map.c:586
       map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1448
       __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:4993
       __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5107
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&psock->link_lock){+...}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       sock_map_add_link net/core/sock_map.c:136 [inline]
       sock_map_update_common+0x31c/0x5b0 net/core/sock_map.c:505
       sock_map_update_elem_sys+0x55b/0x910 net/core/sock_map.c:584
       map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1448
       __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:4993
       __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5107
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&stab->lock);
                               lock(&psock->link_lock);
                               lock(&stab->lock);
  lock(&psock->link_lock);

 *** DEADLOCK ***

3 locks held by syz-executor404/3547:
 #0: ffff88802a711930 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1748 [inline]
 #0: ffff88802a711930 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_sk_acquire net/core/sock_map.c:119 [inline]
 #0: ffff88802a711930 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_update_elem_sys+0x1c8/0x910 net/core/sock_map.c:580
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: sock_map_sk_acquire net/core/sock_map.c:120 [inline]
 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: sock_map_update_elem_sys+0x1d4/0x910 net/core/sock_map.c:580
 #2: ffff88807d8f8240 (&stab->lock){+...}-{2:2}, at: sock_map_update_common+0x1b6/0x5b0 net/core/sock_map.c:495

stack backtrace:
CPU: 0 PID: 3547 Comm: syz-executor404 Not tainted 6.1.90-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 sock_map_add_link net/core/sock_map.c:136 [inline]
 sock_map_update_common+0x31c/0x5b0 net/core/sock_map.c:505
 sock_map_update_elem_sys+0x55b/0x910 net/core/sock_map.c:584
 map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1448
 __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:4993
 __do_sys_bpf kernel/bpf/syscall.c:5109 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5107 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5107
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa89628eb69
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe19945fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007ffe19946198 RCX: 00007fa89628eb69
RDX: 0000000000000020 RSI: 00000000200000c0 RDI: 0000000000000002
RBP: 00007fa896302610 R08: 00007ffe19946198 R09: 00007ffe19946198
R10: 00007ffe19946198 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe19946188 R14: 0000000000000001 R15: 0000000000000001

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/12 14:07 linux-6.1.y 909ba1f1b414 9026e142 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/04/13 07:17 linux-6.1.y bf1e3b1cb1e0 c8349e48 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/06/04 03:49 linux-6.1.y 88690811da69 a1feae05 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/05/26 15:54 linux-6.1.y 88690811da69 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/05/16 01:59 linux-6.1.y 909ba1f1b414 ef5d53ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/05/06 10:10 linux-6.1.y 909ba1f1b414 d884b519 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/05/03 10:20 linux-6.1.y 909ba1f1b414 dd26401e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/04/25 21:14 linux-6.1.y 6741e066ec76 8bdc0f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/04/25 01:03 linux-6.1.y 6741e066ec76 8bdc0f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
2024/04/16 17:03 linux-6.1.y cd5d98c0556c 18f6e127 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in sock_map_update_common
2024/03/29 17:11 linux-6.1.y e5cd595e23c1 c52bcb23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf possible deadlock in sock_map_update_common
* Struck through repros no longer work on HEAD.