====================================================== WARNING: possible circular locking dependency detected 6.1.91-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/4111 is trying to acquire lock: ffff8880569ec0d8 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x69/0x470 kernel/signal.c:1333 but task is already holding lock: ffff8880b993aa18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 raw_spin_rq_lock kernel/sched/sched.h:1354 [inline] rq_lock kernel/sched/sched.h:1644 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11869 sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4686 copy_process+0x2442/0x4060 kernel/fork.c:2384 kernel_clone+0x222/0x920 kernel/fork.c:2682 user_mode_thread+0x12e/0x190 kernel/fork.c:2758 rest_init+0x23/0x300 init/main.c:699 start_kernel+0x0/0x53f init/main.c:894 start_kernel+0x496/0x53f init/main.c:1141 secondary_startup_64_no_verify+0xcf/0xdb -> #1 (&p->pi_lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xad/0x12e0 kernel/sched/core.c:4112 signal_wake_up_state kernel/signal.c:780 [inline] signal_wake_up include/linux/sched/signal.h:457 [inline] complete_signal+0x796/0xbd0 kernel/signal.c:1074 __send_signal_locked+0xb1a/0xdc0 kernel/signal.c:1194 do_notify_parent+0xe2b/0x1100 kernel/signal.c:2120 exit_notify kernel/exit.c:744 [inline] do_exit+0x172e/0x26a0 kernel/exit.c:889 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:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&sighand->siglock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 force_sig_info_to_task+0x69/0x470 kernel/signal.c:1333 force_sig_fault_to_task kernel/signal.c:1724 [inline] force_sig_fault+0x127/0x1d0 kernel/signal.c:1730 __bad_area_nosemaphore+0x126/0x730 arch/x86/mm/fault.c:828 handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x30d/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 copy_user_short_string+0x36/0x40 arch/x86/lib/copy_user_64.S:250 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline] __copy_from_user_inatomic include/linux/uaccess.h:65 [inline] copy_from_user_nofault+0xb1/0x140 mm/maccess.c:125 bpf_probe_read_user_common kernel/trace/bpf_trace.c:167 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:176 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:173 bpf_prog_d20f016a5d369cb4+0x35/0x37 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2314 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2116/0x4550 kernel/sched/core.c:6555 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:658 __put_user_nocheck_8+0x0/0x21 __do_sys_gettimeofday kernel/time/time.c:147 [inline] __se_sys_gettimeofday+0xd5/0x230 kernel/time/time.c:140 emulate_vsyscall+0xc5c/0x1240 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline] handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x154/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 _end+0x6d3da000/0x0 other info that might help us debug this: Chain exists of: &sighand->siglock --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock(&sighand->siglock); *** DEADLOCK *** 2 locks held by syz-executor.2/4111: #0: ffff8880b993aa18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #1: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2314 stack backtrace: CPU: 1 PID: 4111 Comm: syz-executor.2 Not tainted 6.1.91-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 force_sig_info_to_task+0x69/0x470 kernel/signal.c:1333 force_sig_fault_to_task kernel/signal.c:1724 [inline] force_sig_fault+0x127/0x1d0 kernel/signal.c:1730 __bad_area_nosemaphore+0x126/0x730 arch/x86/mm/fault.c:828 handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x30d/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:copy_user_short_string+0x36/0x40 arch/x86/lib/copy_user_64.S:252 Code: 06 4c 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a 06 88 07 48 ff c6 48 ff c7 ff c9 75 f2 31 c0 0f 01 ca c3 <8d> 14 ca eb 02 89 ca eb a1 90 0f 01 cb 83 fa 08 0f 82 95 00 00 00 RSP: 0000:ffffc900031cf8c0 EFLAGS: 00050002 RAX: 000000000000000e RBX: dffffc0000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900031cf928 RBP: ffff88801fcad2f0 R08: 0000000000000005 R09: ffffffff81eeb403 R10: 0000000000000003 R11: ffff88801fcabb80 R12: 1ffff11003f95a5e R13: 0000000000000008 R14: ffffc900031cf928 R15: 0000000000000000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline] __copy_from_user_inatomic include/linux/uaccess.h:65 [inline] copy_from_user_nofault+0xb1/0x140 mm/maccess.c:125 bpf_probe_read_user_common kernel/trace/bpf_trace.c:167 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:176 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:173 bpf_prog_d20f016a5d369cb4+0x35/0x37 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2314 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2116/0x4550 kernel/sched/core.c:6555 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:658 RIP: 0010:__put_user_nocheck_8+0x0/0x21 Code: ff ff 7f 00 00 48 39 d9 73 34 0f 01 cb 89 01 31 c9 0f 01 ca c3 66 0f 1f 44 00 00 48 bb f9 ef ff ff ff 7f 00 00 48 39 d9 73 14 <0f> 01 cb 48 89 01 31 c9 0f 01 ca c3 0f 1f 44 00 00 0f 01 ca b9 f2 RSP: 0000:ffffc900031cfd98 EFLAGS: 00000283 RAX: 000000006647c0ed RBX: 00007fffffffeff9 RCX: 0000000000000019 RDX: 0000000000000000 RSI: ffffffff8aec1340 RDI: ffffffff8b3d4560 RBP: ffffc900031cfe58 R08: dffffc0000000000 R09: fffffbfff1ce710e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc900031cfde0 R13: dffffc0000000000 R14: 1ffff92000639fb8 R15: 0000000000000019 __do_sys_gettimeofday kernel/time/time.c:147 [inline] __se_sys_gettimeofday+0xd5/0x230 kernel/time/time.c:140 emulate_vsyscall+0xc5c/0x1240 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline] handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x154/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0033:_end+0x6d3da000/0x0 Code: Unable to access opcode bytes at 0xffffffffff5fffd6. RSP: 002b:00007f84df1aab38 EFLAGS: 00010246 RAX: ffffffffffffffda RBX: 00007f84de5abf80 RCX: 00007f84de47cee9 RDX: 00007f84df1aab40 RSI: 00007f84df1aac70 RDI: 0000000000000019 RBP: 00007f84de4c949e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f84de5abf80 R15: 00007ffd104eeb88 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 4c 89 07 mov %r8,(%rdi) 3: 48 8d 76 08 lea 0x8(%rsi),%rsi 7: 48 8d 7f 08 lea 0x8(%rdi),%rdi b: ff c9 dec %ecx d: 75 ee jne 0xfffffffd f: 21 d2 and %edx,%edx 11: 74 10 je 0x23 13: 89 d1 mov %edx,%ecx 15: 8a 06 mov (%rsi),%al 17: 88 07 mov %al,(%rdi) 19: 48 ff c6 inc %rsi 1c: 48 ff c7 inc %rdi 1f: ff c9 dec %ecx 21: 75 f2 jne 0x15 23: 31 c0 xor %eax,%eax 25: 0f 01 ca clac 28: c3 ret * 29: 8d 14 ca lea (%rdx,%rcx,8),%edx <-- trapping instruction 2c: eb 02 jmp 0x30 2e: 89 ca mov %ecx,%edx 30: eb a1 jmp 0xffffffd3 32: 90 nop 33: 0f 01 cb stac 36: 83 fa 08 cmp $0x8,%edx 39: 0f 82 95 00 00 00 jb 0xd4