====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc3-syzkaller-00023-g2c71fdf02a95 #0 Not tainted ------------------------------------------------------ syz-fuzzer/5191 is trying to acquire lock: ffff8880204fae58 (&sighand->siglock){-.-.}-{2:2}, at: __lock_task_sighand+0xc2/0x340 kernel/signal.c:1414 but task is already holding lock: ffff88802c238a80 (lock#13){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] ffff88802c238a80 (lock#13){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x7f/0x790 mm/mmap_lock.c:237 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (lock#13){+.+.}-{2:2}: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] __mmap_lock_do_trace_acquire_returned+0x97/0x790 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+0x608/0x770 kernel/bpf/stackmap.c:141 __bpf_get_stack+0x68a/0x710 kernel/bpf/stackmap.c:449 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1985 [inline] bpf_get_stack_raw_tp+0x124/0x160 kernel/trace/bpf_trace.c:1975 bpf_prog_e6cf5f9c69743609+0x42/0x46 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+0x176/0x460 kernel/trace/bpf_trace.c:2422 __traceiter_sched_switch+0x6c/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x252c/0x5d00 kernel/sched/core.c:6743 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6838 synchronize_rcu_expedited+0x612/0x7a0 kernel/rcu/tree_exp.h:954 namespace_unlock+0x1b5/0x490 fs/namespace.c:1573 do_umount fs/namespace.c:1801 [inline] path_umount+0x653/0x10d0 fs/namespace.c:1896 ksys_umount fs/namespace.c:1919 [inline] __do_sys_umount fs/namespace.c:1924 [inline] __se_sys_umount fs/namespace.c:1922 [inline] __ia32_sys_umount+0x16e/0x1a0 fs/namespace.c:1922 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559 raw_spin_rq_lock kernel/sched/sched.h:1385 [inline] _raw_spin_rq_lock_irqsave kernel/sched/sched.h:1404 [inline] rq_lock_irqsave kernel/sched/sched.h:1683 [inline] class_rq_lock_irqsave_constructor kernel/sched/sched.h:1737 [inline] sched_mm_cid_before_execve+0x114/0x5e0 kernel/sched/core.c:12027 exit_signals+0x34d/0x960 kernel/signal.c:3016 do_exit+0x530/0x2c10 kernel/exit.c:837 __do_sys_exit kernel/exit.c:994 [inline] __se_sys_exit kernel/exit.c:992 [inline] __ia32_sys_exit+0x42/0x50 kernel/exit.c:992 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #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 kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 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+0x290/0x300 kernel/signal.c:1453 bpf_send_signal_common+0x2e8/0x3a0 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: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+0x176/0x460 kernel/trace/bpf_trace.c:2422 trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline] __mmap_lock_do_trace_acquire_returned+0x456/0x790 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:5633 [inline] lock_mm_and_find_vma+0xeb/0x580 mm/memory.c:5693 do_user_addr_fault+0x29c/0x1080 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 rep_stos_alternative+0x40/0x80 arch/x86/lib/clear_page_64.S:92 __clear_user arch/x86/include/asm/uaccess_64.h:172 [inline] copy_fpstate_to_sigframe+0x16f/0xaa0 arch/x86/kernel/fpu/signal.c:216 get_sigframe+0x455/0x930 arch/x86/kernel/signal.c:142 x64_setup_rt_frame+0x129/0xce0 arch/x86/kernel/signal_64.c:175 setup_rt_frame arch/x86/kernel/signal.c:223 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x5e6/0x7e0 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x14a/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xdc/0x260 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#13 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#13); lock(&rq->__lock); lock(lock#13); lock(&sighand->siglock); *** DEADLOCK *** 5 locks held by syz-fuzzer/5191: #0: ffff88801fbf4420 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88801fbf4420 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5633 [inline] #0: ffff88801fbf4420 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x35/0x580 mm/memory.c:5693 #1: ffff88802c238a80 (lock#13){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline] #1: ffff88802c238a80 (lock#13){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x7f/0x790 mm/mmap_lock.c:237 #2: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #2: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #2: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: get_memcg_path_buf mm/mmap_lock.c:139 [inline] #2: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: get_mm_memcg_path+0xb1/0x6f0 mm/mmap_lock.c:209 #3: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #3: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x107/0x460 kernel/trace/bpf_trace.c:2422 #4: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #4: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #4: ffffffff8d7b44e0 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x3f/0x340 kernel/signal.c:1397 stack backtrace: CPU: 0 PID: 5191 Comm: syz-fuzzer Not tainted 6.9.0-rc3-syzkaller-00023-g2c71fdf02a95 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 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+0x290/0x300 kernel/signal.c:1453 bpf_send_signal_common+0x2e8/0x3a0 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: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+0x176/0x460 kernel/trace/bpf_trace.c:2422 trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline] __mmap_lock_do_trace_acquire_returned+0x456/0x790 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:5633 [inline] lock_mm_and_find_vma+0xeb/0x580 mm/memory.c:5693 do_user_addr_fault+0x29c/0x1080 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:rep_stos_alternative+0x40/0x80 arch/x86/lib/clear_page_64.S:96 Code: ff c7 48 ff c9 75 f6 c3 cc cc cc cc 48 89 07 48 83 c7 08 83 e9 08 74 ef 83 f9 08 73 ef eb de 66 66 2e 0f 1f 84 00 00 00 00 00 <48> 89 07 48 89 47 08 48 89 47 10 48 89 47 18 48 89 47 20 48 89 47 RSP: 0018:ffffc9000415fb10 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000040 RCX: 0000000000000040 RDX: ffff88801d740000 RSI: ffffffff81336156 RDI: 000000c000061740 RBP: 000000c000061540 R08: 0000000000000000 R09: fffffbfff1f3aaea R10: ffffffff8f9d5757 R11: 0000000000000000 R12: 0000000000000000 R13: 000000c000061540 R14: 0000000008000000 R15: ffff88801d741980 __clear_user arch/x86/include/asm/uaccess_64.h:172 [inline] copy_fpstate_to_sigframe+0x16f/0xaa0 arch/x86/kernel/fpu/signal.c:216 get_sigframe+0x455/0x930 arch/x86/kernel/signal.c:142 x64_setup_rt_frame+0x129/0xce0 arch/x86/kernel/signal_64.c:175 setup_rt_frame arch/x86/kernel/signal.c:223 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x5e6/0x7e0 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x14a/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x472e43 Code: 24 20 c3 cc cc cc cc 48 8b 7c 24 08 8b 74 24 10 8b 54 24 14 4c 8b 54 24 18 4c 8b 44 24 20 44 8b 4c 24 28 b8 ca 00 00 00 0f 05 <89> 44 24 30 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc RSP: 002b:000000c000069e80 EFLAGS: 00000202 ORIG_RAX: 00000000000000ca RAX: fffffffffffffffc RBX: 0000000000000000 RCX: 0000000000472e43 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000024d0d80 RBP: 000000c000069ec8 R08: 0000000000000000 R09: 0000000000000000 R10: 000000c000069eb8 R11: 0000000000000202 R12: 000000c000069eb8 R13: 000000c000059000 R14: 000000c0000064e0 R15: 0000000000000002 ---------------- Code disassembly (best guess): 0: ff c7 inc %edi 2: 48 ff c9 dec %rcx 5: 75 f6 jne 0xfffffffd 7: c3 ret 8: cc int3 9: cc int3 a: cc int3 b: cc int3 c: 48 89 07 mov %rax,(%rdi) f: 48 83 c7 08 add $0x8,%rdi 13: 83 e9 08 sub $0x8,%ecx 16: 74 ef je 0x7 18: 83 f9 08 cmp $0x8,%ecx 1b: 73 ef jae 0xc 1d: eb de jmp 0xfffffffd 1f: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1) 26: 00 00 00 00 * 2a: 48 89 07 mov %rax,(%rdi) <-- trapping instruction 2d: 48 89 47 08 mov %rax,0x8(%rdi) 31: 48 89 47 10 mov %rax,0x10(%rdi) 35: 48 89 47 18 mov %rax,0x18(%rdi) 39: 48 89 47 20 mov %rax,0x20(%rdi) 3d: 48 rex.W 3e: 89 .byte 0x89 3f: 47 rex.RXB