============================================ WARNING: possible recursive locking detected 6.2.0-rc8-syzkaller-00145-g5e725d112e1a #0 Not tainted -------------------------------------------- udevd/4597 is trying to acquire lock: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 but task is already holding lock: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(trace_printk_lock); lock(trace_printk_lock); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by udevd/4597: #0: ffff88801ca4acb8 (kn->active#5){.+.+}-{0:0}, at: kernfs_fop_open+0xab/0xe70 fs/kernfs/file.c:648 #1: ffff8880126522b8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_open_file_mutex_lock fs/kernfs/file.c:56 [inline] #1: ffff8880126522b8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_get_open_node fs/kernfs/file.c:567 [inline] #1: ffff8880126522b8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_fop_open+0x7d8/0xe70 fs/kernfs/file.c:740 #2: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2262 [inline] #2: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2306 #3: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] #3: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 #4: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2262 [inline] #4: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2306 stack backtrace: CPU: 1 PID: 4597 Comm: udevd Not tainted 6.2.0-rc8-syzkaller-00145-g5e725d112e1a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2990 [inline] check_deadlock kernel/locking/lockdep.c:3033 [inline] validate_chain kernel/locking/lockdep.c:3818 [inline] __lock_acquire.cold+0x116/0x3a7 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 bpf_prog_0605f9f479290f07+0x37/0x3b bpf_dispatcher_nop_func include/linux/bpf.h:1082 [inline] __bpf_prog_run include/linux/filter.h:600 [inline] bpf_prog_run include/linux/filter.h:607 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2267 [inline] bpf_trace_run2+0x151/0x3d0 kernel/trace/bpf_trace.c:2306 __bpf_trace_contention_begin+0xb9/0xf0 include/trace/events/lock.h:95 __traceiter_contention_begin+0x5a/0xa0 include/trace/events/lock.h:95 trace_contention_begin.constprop.0+0x143/0x240 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x107/0xb50 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x204/0x2b0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x45/0x60 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 bpf_prog_0605f9f479290f07+0x37/0x3b bpf_dispatcher_nop_func include/linux/bpf.h:1082 [inline] __bpf_prog_run include/linux/filter.h:600 [inline] bpf_prog_run include/linux/filter.h:607 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2267 [inline] bpf_trace_run2+0x151/0x3d0 kernel/trace/bpf_trace.c:2306 __bpf_trace_contention_begin+0xb9/0xf0 include/trace/events/lock.h:95 __traceiter_contention_begin+0x5a/0xa0 include/trace/events/lock.h:95 trace_contention_begin+0x129/0x1e0 include/trace/events/lock.h:95 __mutex_lock_common kernel/locking/mutex.c:605 [inline] __mutex_lock+0x13c/0x1360 kernel/locking/mutex.c:747 kernfs_open_file_mutex_lock fs/kernfs/file.c:56 [inline] kernfs_get_open_node fs/kernfs/file.c:567 [inline] kernfs_fop_open+0x7d8/0xe70 fs/kernfs/file.c:740 do_dentry_open+0x6cc/0x13f0 fs/open.c:882 do_open fs/namei.c:3557 [inline] path_openat+0x1bbc/0x2a50 fs/namei.c:3714 do_filp_open+0x1ba/0x410 fs/namei.c:3741 do_sys_openat2+0x16d/0x4c0 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_openat fs/open.c:1342 [inline] __se_sys_openat fs/open.c:1337 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7feb3b125697 Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f RSP: 002b:00007ffefe718500 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055dc4978c370 RCX: 00007feb3b125697 RDX: 0000000000080000 RSI: 00007ffefe718638 RDI: 00000000ffffff9c RBP: 00007ffefe718638 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000 R13: 000055dc4978c370 R14: 0000000000000001 R15: 0000000000000000