====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc5-syzkaller-00036-g9d1ddab261f3 #0 Not tainted ------------------------------------------------------ syz-executor.0/12118 is trying to acquire lock: ffff8880b953d998 (&pool->lock){-.-.}-{2:2}, at: __queue_work+0x39e/0x1020 kernel/workqueue.c:2360 but task is already holding lock: ffff88805e1e16d8 (&pid->wait_pidfd){....}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:105 [inline] ffff88805e1e16d8 (&pid->wait_pidfd){....}-{2:2}, at: __wake_up+0x1c/0x60 kernel/sched/wait.c:127 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&pid->wait_pidfd){....}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:105 [inline] __wake_up+0x1c/0x60 kernel/sched/wait.c:127 __change_pid+0x199/0x5a0 kernel/pid.c:360 __unhash_process kernel/exit.c:130 [inline] __exit_signal kernel/exit.c:202 [inline] release_task+0xb96/0x1b10 kernel/exit.c:259 exit_notify kernel/exit.c:774 [inline] do_exit+0x1680/0x2c10 kernel/exit.c:898 call_usermodehelper_exec_async+0x379/0x4c0 kernel/umh.c:123 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #3 (&____s->seqcount#5){....}-{0:0}: seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline] read_seqbegin include/linux/seqlock.h:772 [inline] read_seqbegin_or_lock_irqsave include/linux/seqlock.h:1133 [inline] thread_group_cputime+0x164/0x820 kernel/sched/cputime.c:336 thread_group_start_cputime kernel/time/posix-cpu-timers.c:311 [inline] cpu_clock_sample_group+0x44b/0x800 kernel/time/posix-cpu-timers.c:348 set_process_cpu_timer kernel/time/posix-cpu-timers.c:1470 [inline] update_rlimit_cpu+0xc4/0x1b0 kernel/time/posix-cpu-timers.c:49 do_prlimit+0x3d1/0x6d0 kernel/sys.c:1512 __do_sys_prlimit64+0x4be/0xb60 kernel/sys.c:1718 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&sighand->siglock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 kernel/signal.c:1414 lock_task_sighand include/linux/sched/signal.h:746 [inline] do_send_sig_info kernel/signal.c:1300 [inline] group_send_sig_info+0x290/0x300 kernel/signal.c:1453 bpf_send_signal_common+0x2e8/0x3a0 kernel/trace/bpf_trace.c:881 ____bpf_send_signal_thread kernel/trace/bpf_trace.c:898 [inline] bpf_send_signal_thread+0x16/0x20 kernel/trace/bpf_trace.c:896 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run4+0x176/0x460 kernel/trace/bpf_trace.c:2422 __bpf_trace_mmap_lock_acquire_returned+0x134/0x180 include/trace/events/mmap_lock.h:52 trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline] __mmap_lock_do_trace_acquire_returned+0x456/0x790 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:166 [inline] get_mmap_lock_carefully mm/memory.c:5633 [inline] lock_mm_and_find_vma+0xeb/0x580 mm/memory.c:5693 do_user_addr_fault+0x29c/0x1080 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 -> #1 (lock#12){+.+.}-{2:2}: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] __mmap_lock_do_trace_acquire_returned+0x97/0x790 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:166 [inline] stack_map_get_build_id_offset+0x5df/0x7d0 kernel/bpf/stackmap.c:141 __bpf_get_stack+0x6bf/0x700 kernel/bpf/stackmap.c:449 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1985 [inline] bpf_get_stack_raw_tp+0x124/0x160 kernel/trace/bpf_trace.c:1975 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run3+0x167/0x440 kernel/trace/bpf_trace.c:2421 __bpf_trace_workqueue_queue_work+0x101/0x140 include/trace/events/workqueue.h:23 trace_workqueue_queue_work include/trace/events/workqueue.h:23 [inline] __queue_work+0x627/0x1020 kernel/workqueue.c:2382 queue_work_on+0xf4/0x120 kernel/workqueue.c:2435 bpf_prog_load+0x19bb/0x2660 kernel/bpf/syscall.c:2944 __sys_bpf+0x9b4/0x4b40 kernel/bpf/syscall.c:5660 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline] __se_sys_bpf kernel/bpf/syscall.c:5765 [inline] __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5765 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&pool->lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __queue_work+0x39e/0x1020 kernel/workqueue.c:2360 queue_work_on+0xf4/0x120 kernel/workqueue.c:2435 queue_work include/linux/workqueue.h:605 [inline] schedule_work include/linux/workqueue.h:666 [inline] p9_pollwake+0xc1/0x1d0 net/9p/trans_fd.c:538 __wake_up_common+0x131/0x1e0 kernel/sched/wait.c:89 __wake_up_common_lock kernel/sched/wait.c:106 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:127 exit_notify kernel/exit.c:747 [inline] do_exit+0x1448/0x2c10 kernel/exit.c:898 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &pool->lock --> &____s->seqcount#5 --> &pid->wait_pidfd Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pid->wait_pidfd); lock(&____s->seqcount#5); lock(&pid->wait_pidfd); lock(&pool->lock); *** DEADLOCK *** 3 locks held by syz-executor.0/12118: #0: ffffffff8d40a098 (tasklist_lock){.+.+}-{2:2}, at: exit_notify kernel/exit.c:735 [inline] #0: ffffffff8d40a098 (tasklist_lock){.+.+}-{2:2}, at: do_exit+0xac2/0x2c10 kernel/exit.c:898 #1: ffff88805e1e16d8 (&pid->wait_pidfd){....}-{2:2}, at: __wake_up_common_lock kernel/sched/wait.c:105 [inline] #1: ffff88805e1e16d8 (&pid->wait_pidfd){....}-{2:2}, at: __wake_up+0x1c/0x60 kernel/sched/wait.c:127 #2: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #2: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #2: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __queue_work+0xf2/0x1020 kernel/workqueue.c:2324 stack backtrace: CPU: 1 PID: 12118 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00036-g9d1ddab261f3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __queue_work+0x39e/0x1020 kernel/workqueue.c:2360 queue_work_on+0xf4/0x120 kernel/workqueue.c:2435 queue_work include/linux/workqueue.h:605 [inline] schedule_work include/linux/workqueue.h:666 [inline] p9_pollwake+0xc1/0x1d0 net/9p/trans_fd.c:538 __wake_up_common+0x131/0x1e0 kernel/sched/wait.c:89 __wake_up_common_lock kernel/sched/wait.c:106 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:127 exit_notify kernel/exit.c:747 [inline] do_exit+0x1448/0x2c10 kernel/exit.c:898 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efff107dea9 Code: Unable to access opcode bytes at 0x7efff107de7f. RSP: 002b:00007ffd878c11c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 00007efff107dea9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000419 R09: 0000000000000000 R10: 0000001b33920000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001