====================================================== WARNING: possible circular locking dependency detected 6.1.92-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/23827 is trying to acquire lock: ffff88807ce71298 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x69/0x470 kernel/signal.c:1333 but task is already holding lock: ffff8880b983aa18 (&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:1460 [inline] exc_page_fault+0x3bf/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 strncpy_from_kernel_nofault+0x1a3/0x1c0 bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:265 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:313 [inline] bpf_probe_read_compat_str+0x10a/0x180 kernel/trace/bpf_trace.c:306 bpf_prog_c0c47a7d7fe27e4e+0x3a/0x3c 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 __do_sys_gettimeofday kernel/time/time.c:147 [inline] __se_sys_gettimeofday+0xcd/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.1/23827: #0: ffff8880b983aa18 (&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: 0 PID: 23827 Comm: syz-executor.1 Not tainted 6.1.92-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:1460 [inline] exc_page_fault+0x3bf/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:strncpy_from_kernel_nofault+0x1a3/0x1c0 Code: c1 03 38 c1 7c 97 48 8b 3c 24 e8 f8 25 28 00 48 8b 14 24 eb 88 89 f9 80 e1 07 38 c1 7c 9a e8 14 26 28 00 48 8b 54 24 08 eb 8e <49> 89 ec e8 65 a6 d0 ff 48 c7 c3 f2 ff ff ff e9 4d ff ff ff 66 0f RSP: 0000:ffffc900216f7898 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffffffffffffdd RCX: ffff88803a599dc0 RDX: ffffc900216f7928 RSI: ffffffffffffffdd RDI: ffffffffffffffdd RBP: dffffc0000000000 R08: ffffffff813dedc5 R09: ffffed10074b33b9 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffffffffffdd R13: 0000000000000001 R14: 0000000000000000 R15: ffffffffffffffdd bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:265 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:313 [inline] bpf_probe_read_compat_str+0x10a/0x180 kernel/trace/bpf_trace.c:306 bpf_prog_c0c47a7d7fe27e4e+0x3a/0x3c 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:__do_sys_gettimeofday kernel/time/time.c:147 [inline] RIP: 0010:__se_sys_gettimeofday+0xcd/0x230 kernel/time/time.c:140 Code: c7 80 d5 ed 8a be 93 00 00 00 e8 de 66 55 00 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 08 aa 69 00 48 8b 44 24 40 <4c> 89 f9 e8 7b 92 10 09 48 89 cb 41 bd ff ff ff ff 48 89 ce 4c 21 RSP: 0000:ffffc900216f7da0 EFLAGS: 00000246 RAX: 000000007735974d RBX: 00007f91addd4c70 RCX: ffffc900216f7c03 RDX: 0000000000000000 RSI: ffffffff8aec1340 RDI: ffffffff8b3d45e0 RBP: ffffc900216f7e58 R08: dffffc0000000000 R09: fffffbfff1ce712e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc900216f7de0 R13: dffffc0000000000 R14: 1ffff920042defb8 R15: 0000000000000019 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:00007f91addd4b38 EFLAGS: 00010246 RAX: ffffffffffffffda RBX: 00007f91af3b4140 RCX: 00007f91af27cee9 RDX: 00007f91addd4b40 RSI: 00007f91addd4c70 RDI: 0000000000000019 RBP: 00007f91af2c947f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f91af3b4140 R15: 00007ffd9cdcf9f8 ---------------- Code disassembly (best guess): 0: c1 03 38 roll $0x38,(%rbx) 3: c1 7c 97 48 8b sarl $0x8b,0x48(%rdi,%rdx,4) 8: 3c 24 cmp $0x24,%al a: e8 f8 25 28 00 call 0x282607 f: 48 8b 14 24 mov (%rsp),%rdx 13: eb 88 jmp 0xffffff9d 15: 89 f9 mov %edi,%ecx 17: 80 e1 07 and $0x7,%cl 1a: 38 c1 cmp %al,%cl 1c: 7c 9a jl 0xffffffb8 1e: e8 14 26 28 00 call 0x282637 23: 48 8b 54 24 08 mov 0x8(%rsp),%rdx 28: eb 8e jmp 0xffffffb8 * 2a: 49 89 ec mov %rbp,%r12 <-- trapping instruction 2d: e8 65 a6 d0 ff call 0xffd0a697 32: 48 c7 c3 f2 ff ff ff mov $0xfffffffffffffff2,%rbx 39: e9 4d ff ff ff jmp 0xffffff8b 3e: 66 data16 3f: 0f .byte 0xf