====================================================== WARNING: possible circular locking dependency detected 6.1.92-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/6939 is trying to acquire lock: ffff888063b7b798 (&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+0x3b/0x40 arch/x86/lib/copy_user_64.S:253 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_compat kernel/trace/bpf_trace.c:291 [inline] bpf_probe_read_compat+0xe4/0x180 kernel/trace/bpf_trace.c:287 bpf_prog_1878750df62aa1fb+0x40/0x42 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 lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 down_read_trylock+0x24a/0x3b0 kernel/locking/rwsem.c:1562 mmap_read_trylock include/linux/mmap_lock.h:136 [inline] get_mmap_lock_carefully mm/memory.c:5304 [inline] lock_mm_and_find_vma+0x2e/0x2e0 mm/memory.c:5366 do_user_addr_fault arch/x86/mm/fault.c:1343 [inline] handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x169/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 __put_user_nocheck_8+0x3/0x21 __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 *** 3 locks held by syz-executor.0/6939: #0: ffff88801a698158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff88801a698158 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5304 [inline] #0: ffff88801a698158 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2e0 mm/memory.c:5366 #1: ffff8880b993aa18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #2: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #2: ffffffff8d12ac80 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2314 stack backtrace: CPU: 1 PID: 6939 Comm: syz-executor.0 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: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+0x3b/0x40 arch/x86/lib/copy_user_64.S:254 Code: 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 89 f9 83 e1 07 RSP: 0000:ffffc90014f07528 EFLAGS: 00050002 RAX: 000000000000000e RBX: dffffc0000000000 RCX: 0000000000000002 RDX: 0000000000000002 RSI: 0000000000000900 RDI: ffffc90014f075a8 RBP: ffff88805d49f0b0 R08: 0000000000000005 R09: ffffffff81eeb403 R10: 0000000000000003 R11: ffff88805d49d940 R12: 1ffff1100ba93e16 R13: 0000000000000002 R14: ffffc90014f075a8 R15: 0000000000000900 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_compat kernel/trace/bpf_trace.c:291 [inline] bpf_probe_read_compat+0xe4/0x180 kernel/trace/bpf_trace.c:287 bpf_prog_1878750df62aa1fb+0x40/0x42 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:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 Code: 2b 00 74 08 4c 89 f7 e8 7f a9 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0000:ffffc90014f07a20 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920029e0f50 RCX: 1ffff920029e0ef0 RDX: dffffc0000000000 RSI: ffffffff8aec1340 RDI: ffffffff8b3d45e0 RBP: ffffc90014f07b68 R08: dffffc0000000000 R09: fffffbfff209384b R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920029e0f4c R13: dffffc0000000000 R14: ffffc90014f07a80 R15: 0000000000000246 down_read_trylock+0x24a/0x3b0 kernel/locking/rwsem.c:1562 mmap_read_trylock include/linux/mmap_lock.h:136 [inline] get_mmap_lock_carefully mm/memory.c:5304 [inline] lock_mm_and_find_vma+0x2e/0x2e0 mm/memory.c:5366 do_user_addr_fault arch/x86/mm/fault.c:1343 [inline] handle_page_fault arch/x86/mm/fault.c:1462 [inline] exc_page_fault+0x169/0x660 arch/x86/mm/fault.c:1518 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:__put_user_nocheck_8+0x3/0x21 Code: 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 ff ff ff RSP: 0000:ffffc90014f07d98 EFLAGS: 00050283 RAX: 000000006e68114c RBX: 00007fffffffeff9 RCX: 0000000000000019 RDX: 0000000000000000 RSI: ffffffff8aec1340 RDI: ffffffff8b3d45e0 RBP: ffffc90014f07e58 R08: dffffc0000000000 R09: fffffbfff1ce712e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90014f07de0 R13: dffffc0000000000 R14: 1ffff920029e0fb8 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:00007f94f913cb38 EFLAGS: 00010246 RAX: ffffffffffffffda RBX: 00007f94f85b4120 RCX: 00007f94f847cf69 RDX: 00007f94f913cb40 RSI: 00007f94f913cc70 RDI: 0000000000000019 RBP: 00007f94f84da6fe R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f94f85b4120 R15: 00007fff0b10cfb8 ---------------- Code disassembly (best guess): 0: 8d 76 08 lea 0x8(%rsi),%esi 3: 48 8d 7f 08 lea 0x8(%rdi),%rdi 7: ff c9 dec %ecx 9: 75 ee jne 0xfffffff9 b: 21 d2 and %edx,%edx d: 74 10 je 0x1f f: 89 d1 mov %edx,%ecx 11: 8a 06 mov (%rsi),%al 13: 88 07 mov %al,(%rdi) 15: 48 ff c6 inc %rsi 18: 48 ff c7 inc %rdi 1b: ff c9 dec %ecx 1d: 75 f2 jne 0x11 1f: 31 c0 xor %eax,%eax 21: 0f 01 ca clac 24: c3 ret 25: 8d 14 ca lea (%rdx,%rcx,8),%edx 28: eb 02 jmp 0x2c * 2a: 89 ca mov %ecx,%edx <-- trapping instruction 2c: eb a1 jmp 0xffffffcf 2e: 90 nop 2f: 0f 01 cb stac 32: 83 fa 08 cmp $0x8,%edx 35: 0f 82 95 00 00 00 jb 0xd0 3b: 89 f9 mov %edi,%ecx 3d: 83 e1 07 and $0x7,%ecx