syzbot


possible deadlock in bpf_trace_run3

Status: upstream: reported on 2023/12/06 10:14
Reported-by: syzbot+c91e55dbe9697e42023e@syzkaller.appspotmail.com
First crash: 153d, last: 82d

Sample crash report:
------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
5.15.148-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/9959 is trying to acquire lock:
ffffffff8c7fba78 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138

but task is already holding lock:
ffffffff8c975f38 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:382 [inline]
ffffffff8c975f38 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x161/0x3d0 kernel/trace/bpf_trace.c:368

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (trace_printk_lock){....}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       ____bpf_trace_printk kernel/trace/bpf_trace.c:382 [inline]
       bpf_trace_printk+0x161/0x3d0 kernel/trace/bpf_trace.c:368
       0xffffffffa000257b
       bpf_dispatcher_nop_func include/linux/bpf.h:776 [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:1883 [inline]
       bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1921
       __traceiter_sched_switch+0x7d/0xb0 include/trace/events/sched.h:220
       trace_sched_switch include/trace/events/sched.h:220 [inline]
       __schedule+0x1e8d/0x45b0 kernel/sched/core.c:6373
       schedule+0x11b/0x1f0 kernel/sched/core.c:6459
       freezable_schedule include/linux/freezer.h:172 [inline]
       futex_wait_queue_me+0x25b/0x480 kernel/futex/core.c:2863
       futex_wait+0x2f8/0x740 kernel/futex/core.c:2964
       do_futex+0x1414/0x1810 kernel/futex/core.c:3982
       __do_sys_futex kernel/futex/core.c:4059 [inline]
       __se_sys_futex+0x407/0x490 kernel/futex/core.c:4040
       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

-> #2 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368
       raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
       raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
       rq_lock kernel/sched/sched.h:1621 [inline]
       task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11480
       sched_cgroup_fork+0x2d3/0x330 kernel/sched/core.c:4466
       copy_process+0x224a/0x3ef0 kernel/fork.c:2320
       kernel_clone+0x210/0x960 kernel/fork.c:2604
       kernel_thread+0x168/0x1e0 kernel/fork.c:2656
       rest_init+0x21/0x330 init/main.c:703
       start_kernel+0x48c/0x535 init/main.c:1137
       secondary_startup_64_no_verify+0xb1/0xbb

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       try_to_wake_up+0xae/0x1300 kernel/sched/core.c:4030
       up+0x6e/0x90 kernel/locking/semaphore.c:190
       __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:256
       console_unlock+0x1145/0x12b0 kernel/printk/printk.c:2754
       vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2268
       _printk+0xd1/0x111 kernel/printk/printk.c:2293
       ieee80211_sta_find_ibss net/mac80211/ibss.c:1479 [inline]
       ieee80211_ibss_work+0xdc8/0x1480 net/mac80211/ibss.c:1710
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:319
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

-> #0 ((console_sem).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_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138
       __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239
       console_trylock kernel/printk/printk.c:2569 [inline]
       console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867
       vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2267
       _printk+0xd1/0x111 kernel/printk/printk.c:2293
       __warn_printk+0xad/0x120 kernel/panic.c:710
       format_decode+0x12d2/0x1f10 lib/vsprintf.c:2667
       bstr_printf+0x130/0x10c0 lib/vsprintf.c:3238
       ____bpf_trace_printk kernel/trace/bpf_trace.c:383 [inline]
       bpf_trace_printk+0x191/0x3d0 kernel/trace/bpf_trace.c:368
       bpf_prog_12183cdb1cd51dab+0x2e/0xcb0
       bpf_dispatcher_nop_func include/linux/bpf.h:776 [inline]
       __bpf_prog_run include/linux/filter.h:625 [inline]
       bpf_prog_run include/linux/filter.h:632 [inline]
       bpf_test_run+0x3f4/0x8a0 net/bpf/test_run.c:119
       bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
       bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3340
       __sys_bpf+0x3ac/0x670 kernel/bpf/syscall.c:4641
       __do_sys_bpf kernel/bpf/syscall.c:4727 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:4725 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4725
       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:

Chain exists of:
  (console_sem).lock --> &rq->__lock --> trace_printk_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(trace_printk_lock);
                               lock(&rq->__lock);
                               lock(trace_printk_lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

2 locks held by syz-executor.4/9959:
 #0: ffffffff8c91f220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:269
 #1: ffffffff8c975f38 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:382 [inline]
 #1: ffffffff8c975f38 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x161/0x3d0 kernel/trace/bpf_trace.c:368

stack backtrace:
CPU: 0 PID: 9959 Comm: syz-executor.4 Not tainted 5.15.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138
 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239
 console_trylock kernel/printk/printk.c:2569 [inline]
 console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867
 vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2267
 _printk+0xd1/0x111 kernel/printk/printk.c:2293
 __warn_printk+0xad/0x120 kernel/panic.c:710
 format_decode+0x12d2/0x1f10 lib/vsprintf.c:2667
 bstr_printf+0x130/0x10c0 lib/vsprintf.c:3238
 ____bpf_trace_printk kernel/trace/bpf_trace.c:383 [inline]
 bpf_trace_printk+0x191/0x3d0 kernel/trace/bpf_trace.c:368
 bpf_prog_12183cdb1cd51dab+0x2e/0xcb0
 bpf_dispatcher_nop_func include/linux/bpf.h:776 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 bpf_test_run+0x3f4/0x8a0 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
 bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3340
 __sys_bpf+0x3ac/0x670 kernel/bpf/syscall.c:4641
 __do_sys_bpf kernel/bpf/syscall.c:4727 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4725 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4725
 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: 0033:0x7f81270aada9
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:00007f812562b0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f81271d8f80 RCX: 00007f81270aada9
RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00007f81270f747a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f81271d8f80 R15: 00007ffc7cbcb2e8
 </TASK>
Please remove unsupported %� in format string
WARNING: CPU: 0 PID: 9959 at lib/vsprintf.c:2667 format_decode+0x12d2/0x1f10 lib/vsprintf.c:2667
Modules linked in:
CPU: 0 PID: 9959 Comm: syz-executor.4 Not tainted 5.15.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:format_decode+0x12d2/0x1f10 lib/vsprintf.c:2667
Code: a3 09 01 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 07 84 c0 0f 85 30 0c 00 00 41 0f be 36 48 c7 c7 20 a4 db 8a e8 9e 84 1f fd <0f> 0b e9 01 fa ff ff 48 8b 4c 24 18 80 e1 07 38 c1 0f 8c e3 ed ff
RSP: 0018:ffffc90002d876e0 EFLAGS: 00010046
RAX: 739b9cf74b17ca00 RBX: 00000000ffffffdb RCX: 0000000000040000
RDX: ffffc90005451000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc90002d877d0 R08: ffffffff81665d9c R09: ffffed1017344f24
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff0a00ffffff00
R13: ffff0000ffffff00 R14: ffffc90002d879ec R15: 1ffff920005b0f3d
FS:  00007f812562b6c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1bb0e70423 CR3: 000000001de83000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bstr_printf+0x130/0x10c0 lib/vsprintf.c:3238
 ____bpf_trace_printk kernel/trace/bpf_trace.c:383 [inline]
 bpf_trace_printk+0x191/0x3d0 kernel/trace/bpf_trace.c:368
 bpf_prog_12183cdb1cd51dab+0x2e/0xcb0
 bpf_dispatcher_nop_func include/linux/bpf.h:776 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 bpf_test_run+0x3f4/0x8a0 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
 bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3340
 __sys_bpf+0x3ac/0x670 kernel/bpf/syscall.c:4641
 __do_sys_bpf kernel/bpf/syscall.c:4727 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4725 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4725
 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: 0033:0x7f81270aada9
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:00007f812562b0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f81271d8f80 RCX: 00007f81270aada9
RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00007f81270f747a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f81271d8f80 R15: 00007ffc7cbcb2e8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/15 05:01 linux-5.15.y 6139f2a02fe0 d9b1cdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in bpf_trace_run3
2024/01/26 12:23 linux-5.15.y 6139f2a02fe0 cc4a4020 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in bpf_trace_run3
2023/12/30 19:30 linux-5.15.y d93fa2c78854 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in bpf_trace_run3
2023/12/06 10:14 linux-5.15.y 9b91d36ba301 858d62d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in bpf_trace_run3
* Struck through repros no longer work on HEAD.