============================================ WARNING: possible recursive locking detected 6.1.33-syzkaller #0 Not tainted -------------------------------------------- syz-executor304/3555 is trying to acquire lock: ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:390 [inline] ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:376 but task is already holding lock: ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:390 [inline] ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:376 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 syz-executor304/3555: #0: ffff88802259b1b8 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_cleanup_begin kernel/futex/core.c:1066 [inline] #0: ffff88802259b1b8 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_exit_release+0x30/0x1e0 kernel/futex/core.c:1118 #1: ffffffff8cf272a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:305 #2: ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:390 [inline] #2: ffffffff8cf84fd8 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:376 #3: ffffffff8cf272a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:305 stack backtrace: CPU: 0 PID: 3555 Comm: syz-executor304 Not tainted 6.1.33-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2991 [inline] check_deadlock kernel/locking/lockdep.c:3034 [inline] validate_chain+0x4726/0x58e0 kernel/locking/lockdep.c:3819 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669 __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:390 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:376 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:975 [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:2258 [inline] bpf_trace_run2+0x1d6/0x3e0 kernel/trace/bpf_trace.c:2297 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x14c/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x935/0xc50 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x269/0x370 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xdd/0x120 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:390 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:376 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:975 [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:2258 [inline] bpf_trace_run2+0x1d6/0x3e0 kernel/trace/bpf_trace.c:2297 __traceiter_contention_end+0x74/0xa0 include/trace/events/lock.h:122 trace_contention_end+0x12f/0x170 include/trace/events/lock.h:122 __mutex_lock_common+0x41f/0x2520 kernel/locking/mutex.c:612 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799 futex_cleanup_begin kernel/futex/core.c:1066 [inline] futex_exit_release+0x30/0x1e0 kernel/futex/core.c:1118 exit_mm_release+0x16/0x30 kernel/fork.c:1497 exit_mm+0xa9/0x300 kernel/exit.c:535 do_exit+0x67e/0x2300 kernel/exit.c:856 do_group_exit+0x202/0x2b0 kernel/exit.c:1019 __do_sys_exit_group kernel/exit.c:1030 [inline] __se_sys_exit_group kernel/exit.c:1028 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1028 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+0x63/0xcd RIP: 0033:0x7ff967a52c49 Code: 00 49 c7 c0 c0 ff ff ff be e7 00 00 00 ba 3c 00 00 00 eb 12 0f 1f 44 00 00 89 d0 0f 05 48 3d 00 f0 ff ff 77 1c f4 89 f0 0f 05 <48> 3d 00 f0 ff ff 76 e7 f7 d8 64 41 89 00 eb df 0f 1f 80 00 00 00 RSP: 002b:00007fff4aa3f9c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ff967ac8330 RCX: 00007ff967a52c49 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff967ac8330 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001