====================================================== WARNING: possible circular locking dependency detected 6.9.0-syzkaller-g6f130e4d4a5f #0 Not tainted ------------------------------------------------------ syz-executor.4/7415 is trying to acquire lock: ffff8880262ca518 (&sighand->siglock){-.-.}-{2:2}, at: __lock_task_sighand+0x149/0x2d0 kernel/signal.c:1414 but task is already holding lock: ffff8880b9538828 (lock#10){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] ffff8880b9538828 (lock#10){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x8f/0x630 mm/mmap_lock.c:237 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (lock#10){+.+.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 local_lock_acquire include/linux/local_lock_internal.h:29 [inline] __mmap_lock_do_trace_acquire_returned+0xa8/0x630 mm/mmap_lock.c:237 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:166 [inline] stack_map_get_build_id_offset+0x9b2/0x9d0 kernel/bpf/stackmap.c:141 __bpf_get_stack+0x4ad/0x5a0 kernel/bpf/stackmap.c:449 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1994 [inline] bpf_get_stack_raw_tp+0x1a3/0x240 kernel/trace/bpf_trace.c:1984 0xffffffffa0002136 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444 trace_tlb_flush+0x118/0x140 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x7cb/0xae0 context_switch kernel/sched/core.c:5392 [inline] __schedule+0x1066/0x4a50 kernel/sched/core.c:6745 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6924 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6948 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194 __debug_check_no_obj_freed lib/debugobjects.c:998 [inline] debug_check_no_obj_freed+0x561/0x580 lib/debugobjects.c:1019 free_pages_prepare mm/page_alloc.c:1147 [inline] free_unref_page_prepare+0x322/0xab0 mm/page_alloc.c:2347 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487 vfree+0x186/0x2e0 mm/vmalloc.c:3340 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:882 [inline] get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline] do_ip6t_get_ctl+0x11eb/0x1820 net/ipv6/netfilter/ip6_tables.c:1677 nf_getsockopt+0x299/0x2c0 net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x263/0x380 net/ipv6/ipv6_sockglue.c:1494 tcp_getsockopt+0x163/0x1c0 net/ipv4/tcp.c:4399 do_sock_getsockopt+0x373/0x850 net/socket.c:2373 __sys_getsockopt+0x271/0x330 net/socket.c:2402 __do_sys_getsockopt net/socket.c:2412 [inline] __se_sys_getsockopt net/socket.c:2409 [inline] __x64_sys_getsockopt+0xb5/0xd0 net/socket.c:2409 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 -> #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:1406 [inline] _raw_spin_rq_lock_irqsave kernel/sched/sched.h:1425 [inline] rq_lock_irqsave kernel/sched/sched.h:1686 [inline] class_rq_lock_irqsave_constructor kernel/sched/sched.h:1740 [inline] sched_mm_cid_exit_signals+0x17b/0x4b0 kernel/sched/core.c:12004 exit_signals+0x2a1/0x5c0 kernel/signal.c:3016 do_exit+0x6a8/0x27e0 kernel/exit.c:836 __do_sys_exit kernel/exit.c:993 [inline] __se_sys_exit kernel/exit.c:991 [inline] __pfx___ia32_sys_exit+0x0/0x10 kernel/exit.c:991 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 __lock_task_sighand+0x149/0x2d0 kernel/signal.c:1414 lock_task_sighand include/linux/sched/signal.h:746 [inline] do_send_sig_info kernel/signal.c:1300 [inline] group_send_sig_info+0x274/0x310 kernel/signal.c:1453 bpf_send_signal_common+0x2dd/0x430 kernel/trace/bpf_trace.c:881 ____bpf_send_signal_thread kernel/trace/bpf_trace.c:898 [inline] bpf_send_signal_thread+0x16/0x20 kernel/trace/bpf_trace.c:896 bpf_prog_7bb747c56a8bcba8+0x1d/0x25 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2446 trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline] __mmap_lock_do_trace_acquire_returned+0x5c8/0x630 mm/mmap_lock.c:237 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:166 [inline] get_mmap_lock_carefully mm/memory.c:5628 [inline] lock_mm_and_find_vma+0x213/0x2f0 mm/memory.c:5688 do_user_addr_fault arch/x86/mm/fault.c:1355 [inline] handle_page_fault arch/x86/mm/fault.c:1475 [inline] exc_page_fault+0x1a9/0x8a0 arch/x86/mm/fault.c:1533 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 __put_user_8+0x11/0x20 arch/x86/lib/putuser.S:105 clear_rseq_cs kernel/rseq.c:257 [inline] rseq_ip_fixup kernel/rseq.c:291 [inline] __rseq_handle_notify_resume+0x666/0x14e0 kernel/rseq.c:329 rseq_handle_notify_resume include/linux/rseq.h:38 [inline] resume_user_mode_work include/linux/resume_user_mode.h:62 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x114/0x370 kernel/entry/common.c:218 do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sighand->siglock --> &rq->__lock --> lock#10 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#10); lock(&rq->__lock); lock(lock#10); lock(&sighand->siglock); *** DEADLOCK *** 5 locks held by syz-executor.4/7415: #0: ffff88804c74d720 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88804c74d720 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5628 [inline] #0: ffff88804c74d720 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5688 #1: ffff8880b9538828 (lock#10){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] #1: ffff8880b9538828 (lock#10){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x8f/0x630 mm/mmap_lock.c:237 #2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: get_memcg_path_buf mm/mmap_lock.c:139 [inline] #2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: get_mm_memcg_path+0xb1/0x600 mm/mmap_lock.c:209 #3: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline] #3: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x244/0x590 kernel/trace/bpf_trace.c:2446 #4: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #4: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #4: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x29/0x2d0 kernel/signal.c:1397 stack backtrace: CPU: 1 PID: 7415 Comm: syz-executor.4 Not tainted 6.9.0-syzkaller-g6f130e4d4a5f #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+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 __lock_task_sighand+0x149/0x2d0 kernel/signal.c:1414 lock_task_sighand include/linux/sched/signal.h:746 [inline] do_send_sig_info kernel/signal.c:1300 [inline] group_send_sig_info+0x274/0x310 kernel/signal.c:1453 bpf_send_signal_common+0x2dd/0x430 kernel/trace/bpf_trace.c:881 ____bpf_send_signal_thread kernel/trace/bpf_trace.c:898 [inline] bpf_send_signal_thread+0x16/0x20 kernel/trace/bpf_trace.c:896 bpf_prog_7bb747c56a8bcba8+0x1d/0x25 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2446 trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline] __mmap_lock_do_trace_acquire_returned+0x5c8/0x630 mm/mmap_lock.c:237 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:166 [inline] get_mmap_lock_carefully mm/memory.c:5628 [inline] lock_mm_and_find_vma+0x213/0x2f0 mm/memory.c:5688 do_user_addr_fault arch/x86/mm/fault.c:1355 [inline] handle_page_fault arch/x86/mm/fault.c:1475 [inline] exc_page_fault+0x1a9/0x8a0 arch/x86/mm/fault.c:1533 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:__put_user_8+0x11/0x20 arch/x86/lib/putuser.S:107 Code: 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <48> 89 01 31 c9 0f 01 ca c3 cc cc cc cc 66 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90005997d98 EFLAGS: 00050202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000055556180cda8 RDX: 0000000000000000 RSI: ffffffff8bcac720 RDI: ffffffff8c1fada0 RBP: ffffc90005997ec8 R08: ffffffff8facbbef R09: 1ffffffff1f5977d R10: dffffc0000000000 R11: fffffbfff1f5977e R12: ffffc90005997e50 R13: ffffc90005997fd8 R14: dffffc0000000000 R15: ffff888020c21558 clear_rseq_cs kernel/rseq.c:257 [inline] rseq_ip_fixup kernel/rseq.c:291 [inline] __rseq_handle_notify_resume+0x666/0x14e0 kernel/rseq.c:329 rseq_handle_notify_resume include/linux/rseq.h:38 [inline] resume_user_mode_work include/linux/resume_user_mode.h:62 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x114/0x370 kernel/entry/common.c:218 do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc420a79f13 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffee3155138 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: 00000000000000d1 RBX: 0000000000000000 RCX: 00007fc420a79f13 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 000055556180c750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 ---------------- Code disassembly (best guess): 0: 84 00 test %al,(%rax) 2: 00 00 add %al,(%rax) 4: 00 00 add %al,(%rax) 6: 0f 1f 00 nopl (%rax) 9: 90 nop a: 90 nop b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: f3 0f 1e fa endbr64 1d: 48 89 cb mov %rcx,%rbx 20: 48 c1 fb 3f sar $0x3f,%rbx 24: 48 09 d9 or %rbx,%rcx 27: 0f 01 cb stac * 2a: 48 89 01 mov %rax,(%rcx) <-- trapping instruction 2d: 31 c9 xor %ecx,%ecx 2f: 0f 01 ca clac 32: c3 ret 33: cc int3 34: cc int3 35: cc int3 36: cc int3 37: 66 90 xchg %ax,%ax 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop