============================================ WARNING: possible recursive locking detected 6.1.0-syzkaller-04343-gd039535850ee #0 Not tainted -------------------------------------------- strace-static-x/5070 is trying to acquire lock: ffffffff8c81a238 (trace_printk_lock){-...}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] ffffffff8c81a238 (trace_printk_lock){-...}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 but task is already holding lock: ffffffff8c81a238 (trace_printk_lock){-...}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] ffffffff8c81a238 (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 4 locks held by strace-static-x/5070: #0: ffff88802a4a5868 (&pipe->mutex/1){+.+.}-{3:3}, at: __pipe_lock fs/pipe.c:103 [inline] #0: ffff88802a4a5868 (&pipe->mutex/1){+.+.}-{3:3}, at: pipe_write+0x136/0x1bf0 fs/pipe.c:431 #1: ffffffff8c7917c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] #1: ffffffff8c7917c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2302 #2: ffffffff8c81a238 (trace_printk_lock){-...}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] #2: ffffffff8c81a238 (trace_printk_lock){-...}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 #3: ffffffff8c7917c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] #3: ffffffff8c7917c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2302 stack backtrace: CPU: 0 PID: 5070 Comm: strace-static-x Not tainted 6.1.0-syzkaller-04343-gd039535850ee #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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:2263 [inline] bpf_trace_run2+0x151/0x3d0 kernel/trace/bpf_trace.c:2302 __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:2263 [inline] bpf_trace_run2+0x151/0x3d0 kernel/trace/bpf_trace.c:2302 __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 __pipe_lock fs/pipe.c:103 [inline] pipe_write+0x136/0x1bf0 fs/pipe.c:431 call_write_iter include/linux/fs.h:2186 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x9ed/0xdd0 fs/read_write.c:584 ksys_write+0x1ec/0x250 fs/read_write.c:637 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: 0033:0x4e8593 Code: c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18 RSP: 002b:00007ffc46517a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 00000000004e8593 RDX: 0000000000000014 RSI: 000000000231f140 RDI: 0000000000000002 RBP: 000000000231f140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000014 R13: 000000000063f460 R14: 0000000000000014 R15: 0000000000000001