============================================ WARNING: possible recursive locking detected 6.2.0-rc8-syzkaller-00145-g5e725d112e1a #0 Not tainted -------------------------------------------- syz-executor.1/12119 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 4 locks held by syz-executor.1/12119: #0: ffff88801d96d590 (&u->iolock){+.+.}-{3:3}, at: __unix_dgram_recvmsg+0x22a/0xb90 net/unix/af_unix.c:2442 #1: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2262 [inline] #1: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2306 #2: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline] #2: ffffffff8c81b578 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xd3/0x170 kernel/trace/bpf_trace.c:377 #3: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2262 [inline] #3: ffffffff8c7922a0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xbd/0x3d0 kernel/trace/bpf_trace.c:2306 stack backtrace: CPU: 2 PID: 12119 Comm: syz-executor.1 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 __unix_dgram_recvmsg+0x22a/0xb90 net/unix/af_unix.c:2442 unix_dgram_recvmsg+0xc4/0xf0 net/unix/af_unix.c:2542 sock_recvmsg_nosec net/socket.c:998 [inline] ____sys_recvmsg+0x53c/0x610 net/socket.c:2696 ___sys_recvmsg+0xf2/0x180 net/socket.c:2740 do_recvmmsg+0x554/0x6e0 net/socket.c:2826 __sys_recvmmsg+0x242/0x250 net/socket.c:2913 __do_compat_sys_recvmmsg_time32 net/compat.c:417 [inline] __se_compat_sys_recvmmsg_time32 net/compat.c:413 [inline] __ia32_compat_sys_recvmmsg_time32+0xc6/0x160 net/compat.c:413 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f76549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f505cc EFLAGS: 00000296 ORIG_RAX: 0000000000000151 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200000c0 RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi