syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.156-syzkaller #0 Not tainted
------------------------------------------------------
sshd/3497 is trying to acquire lock:
ffff8880b9b35bb8 (lock#8){+.+.}-{2:2}, at: local_lock_acquire+0xd/0x170 include/linux/local_lock_internal.h:28

but task is already holding lock:
ffff8880b9b3a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&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:704
       start_kernel+0x48c/0x540 init/main.c:1138
       secondary_startup_64_no_verify+0xb1/0xbb

-> #2 (&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
       signal_wake_up_state kernel/signal.c:770 [inline]
       signal_wake_up include/linux/sched/signal.h:421 [inline]
       complete_signal+0x5a0/0x9a0 kernel/signal.c:1062
       __send_signal+0xaaf/0xd40 kernel/signal.c:1182
       do_notify_parent+0xc1e/0xf00 kernel/signal.c:2113
       exit_notify kernel/exit.c:729 [inline]
       do_exit+0x1464/0x2480 kernel/exit.c:892
       do_group_exit+0x144/0x310 kernel/exit.c:994
       __do_sys_exit_group kernel/exit.c:1005 [inline]
       __se_sys_exit_group kernel/exit.c:1003 [inline]
       __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&sighand->siglock){....}-{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
       __lock_task_sighand+0x11a/0x290 kernel/signal.c:1404
       lock_task_sighand include/linux/sched/signal.h:704 [inline]
       do_send_sig_info kernel/signal.c:1293 [inline]
       group_send_sig_info+0x23f/0x2d0 kernel/signal.c:1442
       bpf_send_signal_common+0x2d8/0x420 kernel/trace/bpf_trace.c:824
       ____bpf_send_signal kernel/trace/bpf_trace.c:829 [inline]
       bpf_send_signal+0x15/0x20 kernel/trace/bpf_trace.c:827
       bpf_prog_9fbc3d1d47c9b36c+0x302/0x514
       bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
       bpf_trace_run4+0x1ea/0x390 kernel/trace/bpf_trace.c:1919
       trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:44 [inline]
       __mmap_lock_do_trace_acquire_returned+0x2d6/0x340 mm/mmap_lock.c:237
       __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline]
       mmap_read_trylock include/linux/mmap_lock.h:137 [inline]
       do_user_addr_fault arch/x86/mm/fault.c:1329 [inline]
       handle_page_fault arch/x86/mm/fault.c:1476 [inline]
       exc_page_fault+0x59c/0x740 arch/x86/mm/fault.c:1532
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
       strncpy_from_user+0x170/0x370 lib/strncpy_from_user.c:139
       strncpy_from_bpfptr include/linux/bpfptr.h:84 [inline]
       bpf_prog_load+0x185/0x1b60 kernel/bpf/syscall.c:2238
       __sys_bpf+0x343/0x670 kernel/bpf/syscall.c:4651
       __do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
       __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (lock#8){+.+.}-{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
       local_lock_acquire+0x29/0x170 include/linux/local_lock_internal.h:29
       __mmap_lock_do_trace_acquire_returned+0x7c/0x340 mm/mmap_lock.c:237
       __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline]
       mmap_read_trylock include/linux/mmap_lock.h:137 [inline]
       stack_map_get_build_id_offset+0x612/0x930 kernel/bpf/stackmap.c:185
       __bpf_get_stack+0x495/0x570 kernel/bpf/stackmap.c:496
       ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1490 [inline]
       bpf_get_stack_raw_tp+0x1b2/0x220 kernel/trace/bpf_trace.c:1480
       bpf_prog_e6cf5f9c69743609+0x3a/0xe2c
       bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
       bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1918
       __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
       schedule_hrtimeout_range_clock+0x2b3/0x4a0 kernel/time/hrtimer.c:2308
       poll_schedule_timeout+0x10c/0x150 fs/select.c:243
       do_poll fs/select.c:964 [inline]
       do_sys_poll+0xd61/0x11f0 fs/select.c:1014
       __do_sys_ppoll fs/select.c:1120 [inline]
       __se_sys_ppoll+0x29c/0x330 fs/select.c:1100
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  lock#8 --> &p->pi_lock --> &rq->__lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->__lock);
                               lock(&p->pi_lock);
                               lock(&rq->__lock);
  lock(lock#8);

 *** DEADLOCK ***

3 locks held by sshd/3497:
 #0: ffff8880b9b3a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffffffff8c91fb20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #2: ffff8880244a1628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #2: ffff8880244a1628 (&mm->mmap_lock){++++}-{3:3}, at: stack_map_get_build_id_offset+0x23e/0x930 kernel/bpf/stackmap.c:185

stack backtrace:
CPU: 1 PID: 3497 Comm: sshd Not tainted 5.15.156-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 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
 local_lock_acquire+0x29/0x170 include/linux/local_lock_internal.h:29
 __mmap_lock_do_trace_acquire_returned+0x7c/0x340 mm/mmap_lock.c:237
 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline]
 mmap_read_trylock include/linux/mmap_lock.h:137 [inline]
 stack_map_get_build_id_offset+0x612/0x930 kernel/bpf/stackmap.c:185
 __bpf_get_stack+0x495/0x570 kernel/bpf/stackmap.c:496
 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1490 [inline]
 bpf_get_stack_raw_tp+0x1b2/0x220 kernel/trace/bpf_trace.c:1480
 bpf_prog_e6cf5f9c69743609+0x3a/0xe2c
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1918
 __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
 schedule_hrtimeout_range_clock+0x2b3/0x4a0 kernel/time/hrtimer.c:2308
 poll_schedule_timeout+0x10c/0x150 fs/select.c:243
 do_poll fs/select.c:964 [inline]
 do_sys_poll+0xd61/0x11f0 fs/select.c:1014
 __do_sys_ppoll fs/select.c:1120 [inline]
 __se_sys_ppoll+0x29c/0x330 fs/select.c:1100
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe14d92aad5
Code: 85 d2 74 0d 0f 10 02 48 8d 54 24 20 0f 11 44 24 20 64 8b 04 25 18 00 00 00 85 c0 75 27 41 b8 08 00 00 00 b8 0f 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 75 48 8b 15 24 73 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fffb864af60 EFLAGS: 00000246 ORIG_RAX: 000000000000010f
RAX: ffffffffffffffda RBX: 00000000000668a0 RCX: 00007fe14d92aad5
RDX: 00007fffb864af80 RSI: 0000000000000004 RDI: 000056401c5a5a80
RBP: 000056401c5a6240 R08: 0000000000000008 R09: 0000000000000000
R10: 00007fffb864b068 R11: 0000000000000246 R12: 000056401bfe0aa4
R13: 0000000000000001 R14: 000056401bfe13e8 R15: 00007fffb864afe8
 </TASK>