====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc5-syzkaller-00329-g5d12ed4bea43 #0 Not tainted ------------------------------------------------------ syz-executor.0/12438 is trying to acquire lock: ffff8880238cef18 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 but task is already holding lock: ffff8880b953e698 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 raw_spin_rq_lock kernel/sched/sched.h:1387 [inline] _raw_spin_rq_lock_irqsave kernel/sched/sched.h:1406 [inline] rq_lock_irqsave kernel/sched/sched.h:1685 [inline] class_rq_lock_irqsave_constructor kernel/sched/sched.h:1739 [inline] sched_mm_cid_exit_signals+0x17b/0x4b0 kernel/sched/core.c:12005 exit_signals+0x2a1/0x5c0 kernel/signal.c:3016 do_exit+0x6a8/0x27e0 kernel/exit.c:837 __do_sys_exit kernel/exit.c:994 [inline] __se_sys_exit kernel/exit.c:992 [inline] __pfx___ia32_sys_exit+0x0/0x10 kernel/exit.c:992 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sighand->siglock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 force_sig_fault_to_task kernel/signal.c:1733 [inline] force_sig_fault+0x12c/0x1d0 kernel/signal.c:1738 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:125 [inline] __copy_from_user_inatomic include/linux/uaccess.h:87 [inline] copy_from_user_nofault+0xbc/0x150 mm/maccess.c:125 bpf_probe_read_user_common kernel/trace/bpf_trace.c:179 [inline] ____bpf_probe_read_compat kernel/trace/bpf_trace.c:292 [inline] bpf_probe_read_compat+0xe9/0x180 kernel/trace/bpf_trace.c:288 bpf_prog_1878750df62aa1fb+0x48/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run4+0x25c/0x490 kernel/trace/bpf_trace.c:2422 __traceiter_sched_switch+0x9a/0xd0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2587/0x4a50 kernel/sched/core.c:6743 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7068 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 native_save_fl arch/x86/include/asm/irqflags.h:19 [inline] arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline] arch_local_irq_save arch/x86/include/asm/irqflags.h:103 [inline] seqcount_lockdep_reader_access+0x9a/0x220 include/linux/seqlock.h:71 ktime_get_real_ts64+0xa2/0x470 kernel/time/timekeeping.c:824 __do_sys_gettimeofday kernel/time/time.c:146 [inline] __se_sys_gettimeofday+0xa5/0x240 kernel/time/time.c:140 emulate_vsyscall+0xe23/0x1290 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1346 [inline] handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x160/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 _end+0x6a9da000/0x0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&sighand->siglock); lock(&rq->__lock); lock(&sighand->siglock); *** DEADLOCK *** 2 locks held by syz-executor.0/12438: #0: ffff8880b953e698 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16e/0x490 kernel/trace/bpf_trace.c:2422 stack backtrace: CPU: 1 PID: 12438 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00329-g5d12ed4bea43 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 force_sig_fault_to_task kernel/signal.c:1733 [inline] force_sig_fault+0x12c/0x1d0 kernel/signal.c:1738 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline] RIP: 0010:raw_copy_from_user arch/x86/include/asm/uaccess_64.h:125 [inline] RIP: 0010:__copy_from_user_inatomic include/linux/uaccess.h:87 [inline] RIP: 0010:copy_from_user_nofault+0xbc/0x150 mm/maccess.c:125 Code: 00 4c 89 ff 44 89 f6 e8 d2 72 2c 00 4c 89 ff 4c 89 f6 31 d2 e8 95 ef 3a 00 0f 01 cb 4c 89 ff 4c 89 f1 4c 89 ee f3 a4 0f 1f 00 <48> 89 cb 0f 01 ca 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 RSP: 0000:ffffc900120376d0 EFLAGS: 00050082 RAX: ffffffff82091e7e RBX: dffffc0000000000 RCX: 0000000000000002 RDX: ffffc9000a7ef000 RSI: 0000000000000900 RDI: ffffc90012037748 RBP: ffff8880225db584 R08: 0000000000000005 R09: ffffffff82091e67 R10: 0000000000000003 R11: ffff8880225d9e00 R12: 1ffff110044bb6b0 R13: 0000000000000900 R14: 0000000000000002 R15: ffffc90012037748 bpf_probe_read_user_common kernel/trace/bpf_trace.c:179 [inline] ____bpf_probe_read_compat kernel/trace/bpf_trace.c:292 [inline] bpf_probe_read_compat+0xe9/0x180 kernel/trace/bpf_trace.c:288 bpf_prog_1878750df62aa1fb+0x48/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run4+0x25c/0x490 kernel/trace/bpf_trace.c:2422 __traceiter_sched_switch+0x9a/0xd0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2587/0x4a50 kernel/sched/core.c:6743 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7068 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:19 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:103 [inline] RIP: 0010:seqcount_lockdep_reader_access+0x9a/0x220 include/linux/seqlock.h:71 Code: 43 c6 44 27 0b f3 e8 45 33 12 00 4c 89 f3 48 c1 eb 03 42 80 3c 23 00 74 08 4c 89 f7 e8 bf d3 76 00 48 c7 44 24 40 00 00 00 00 <9c> 8f 44 24 40 42 80 3c 23 00 74 08 4c 89 f7 e8 b2 d2 76 00 4c 8d RSP: 0000:ffffc90012037c20 EFLAGS: 00000246 RAX: ffffffff8183cb9b RBX: 1ffff92002406f8c RCX: 0000000000040000 RDX: ffffc9000a7ef000 RSI: 0000000000002500 RDI: 0000000000002501 RBP: ffffc90012037cd0 R08: ffffffff8183c723 R09: ffffc90012037de0 R10: dffffc0000000000 R11: fffff52002406fbe R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffc90012037c60 R15: 1ffff92002406f84 ktime_get_real_ts64+0xa2/0x470 kernel/time/timekeeping.c:824 __do_sys_gettimeofday kernel/time/time.c:146 [inline] __se_sys_gettimeofday+0xa5/0x240 kernel/time/time.c:140 emulate_vsyscall+0xe23/0x1290 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1346 [inline] handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x160/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:_end+0x6a9da000/0x0 Code: Unable to access opcode bytes at 0xffffffffff5fffd6. RSP: 002b:00007fdd18201b38 EFLAGS: 00010246 RAX: ffffffffffffffda RBX: 00007fdd175ac120 RCX: 00007fdd1747dea9 RDX: 00007fdd18201b40 RSI: 00007fdd18201c70 RDI: 0000000000000019 RBP: 00007fdd174ca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fdd175ac120 R15: 00007ffdc0b9b438 ---------------- Code disassembly (best guess): 0: 00 4c 89 ff add %cl,-0x1(%rcx,%rcx,4) 4: 44 89 f6 mov %r14d,%esi 7: e8 d2 72 2c 00 call 0x2c72de c: 4c 89 ff mov %r15,%rdi f: 4c 89 f6 mov %r14,%rsi 12: 31 d2 xor %edx,%edx 14: e8 95 ef 3a 00 call 0x3aefae 19: 0f 01 cb stac 1c: 4c 89 ff mov %r15,%rdi 1f: 4c 89 f1 mov %r14,%rcx 22: 4c 89 ee mov %r13,%rsi 25: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 27: 0f 1f 00 nopl (%rax) * 2a: 48 89 cb mov %rcx,%rbx <-- trapping instruction 2d: 0f 01 ca clac 30: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 37: fc ff df 3a: 41 0f b6 04 04 movzbl (%r12,%rax,1),%eax 3f: 84 .byte 0x84