syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0 Not tainted
------------------------------------------------------
syz-executor.0/7752 is trying to acquire lock:
ffff888029b20958 (&sighand->siglock){-.-.}-{2:2}, at: __lock_task_sighand+0xc2/0x340 kernel/signal.c:1414

but task is already holding lock:
ffff8880b9438a80 (lock#10){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff8880b9438a80 (lock#10){+.+.}-{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#10){+.+.}-{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+0x5df/0x7d0 kernel/bpf/stackmap.c:141
       __bpf_get_stack+0x6bf/0x700 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_ec3b2eefa702d8d3+0x42/0x4a
       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_run2+0x154/0x420 kernel/trace/bpf_trace.c:2420
       __bpf_trace_tlb_flush+0xd2/0x110 include/trace/events/tlb.h:38
       trace_tlb_flush+0xf3/0x170 include/trace/events/tlb.h:38
       switch_mm_irqs_off+0x68b/0xbc0 arch/x86/mm/tlb.c:642
       context_switch kernel/sched/core.c:5393 [inline]
       __schedule+0xd2b/0x5d00 kernel/sched/core.c:6746
       preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6925
       preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12
       __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
       _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
       spin_unlock include/linux/spinlock.h:391 [inline]
       __text_poke+0x618/0xca0 arch/x86/kernel/alternative.c:1961
       text_poke_bp_batch+0x1cd/0x760 arch/x86/kernel/alternative.c:2293
       text_poke_flush arch/x86/kernel/alternative.c:2487 [inline]
       text_poke_flush arch/x86/kernel/alternative.c:2484 [inline]
       text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2494
       arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
       jump_label_update+0x1d7/0x400 kernel/jump_label.c:829
       static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:205
       static_key_enable+0x1a/0x20 kernel/jump_label.c:218
       tracepoint_add_func+0xa4c/0xe50 kernel/tracepoint.c:361
       tracepoint_probe_register_prio_may_exist+0xbd/0x110 kernel/tracepoint.c:482
       tracepoint_probe_register_may_exist include/linux/tracepoint.h:52 [inline]
       __bpf_probe_register kernel/trace/bpf_trace.c:2446 [inline]
       bpf_probe_register+0x164/0x1d0 kernel/trace/bpf_trace.c:2452
       bpf_raw_tp_link_attach+0x2e5/0x610 kernel/bpf/syscall.c:3865
       bpf_raw_tracepoint_open kernel/bpf/syscall.c:3892 [inline]
       __sys_bpf+0x3a0/0x4b40 kernel/bpf/syscall.c:5702
       __do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
       __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5765
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #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: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_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]
       __x64_sys_exit+0x42/0x50 kernel/exit.c:992
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 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 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/0x29
       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+0x179/0x460 kernel/trace/bpf_trace.c:2422
       __bpf_trace_mmap_lock_acquire_returned+0x134/0x180 include/trace/events/mmap_lock.h:52
       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
       copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
       raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
       _copy_to_user lib/usercopy.c:41 [inline]
       _copy_to_user+0xa7/0xc0 lib/usercopy.c:34
       copy_to_user include/linux/uaccess.h:191 [inline]
       __do_sys_newuname+0x11b/0x270 kernel/sys.c:1313
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       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.0/7752:
 #0: ffff88807f42cda0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88807f42cda0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5633 [inline]
 #0: ffff88807f42cda0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x35/0x580 mm/memory.c:5693
 #1: ffff8880b9438a80 (lock#10){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
 #1: ffff8880b9438a80 (lock#10){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x7f/0x790 mm/mmap_lock.c:237
 #2: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #2: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #2: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: get_memcg_path_buf mm/mmap_lock.c:139 [inline]
 #2: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: get_mm_memcg_path+0xb1/0x6f0 mm/mmap_lock.c:209
 #3: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #3: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #3: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
 #3: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x107/0x460 kernel/trace/bpf_trace.c:2422
 #4: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #4: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #4: ffffffff8d9b4f20 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x3f/0x340 kernel/signal.c:1397

stack backtrace:
CPU: 0 PID: 7752 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __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/0x29
 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+0x179/0x460 kernel/trace/bpf_trace.c:2422
 __bpf_trace_mmap_lock_acquire_returned+0x134/0x180 include/trace/events/mmap_lock.h:52
 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:copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
RIP: 0010:_copy_to_user lib/usercopy.c:41 [inline]
RIP: 0010:_copy_to_user+0xa7/0xc0 lib/usercopy.c:34
Code: 89 ee 48 89 ef e8 09 88 0e fd 4d 85 f6 75 b5 e8 af 8d 0e fd 89 de 4c 89 e7 e8 35 68 6a fd 0f 01 cb 48 89 d9 48 89 ef 4c 89 e6 <f3> a4 0f 1f 00 0f 01 ca 48 89 cb eb 8d 66 66 2e 0f 1f 84 00 00 00
RSP: 0018:ffffc9000953fca8 EFLAGS: 00050297
RAX: 0000000000000001 RBX: 0000000000000186 RCX: 0000000000000186
RDX: fffff520012a7fd1 RSI: ffffc9000953fd08 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff520012a7fd1
R10: 0000000000000005 R11: 0000000000000000 R12: ffffc9000953fd08
R13: 0000000000000186 R14: 0000000000000000 R15: 0000000000000000
 copy_to_user include/linux/uaccess.h:191 [inline]
 __do_sys_newuname+0x11b/0x270 kernel/sys.c:1313
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f12e0a7dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f12e05ff0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000003f
RAX: ffffffffffffffda RBX: 00007f12e0babf80 RCX: 00007f12e0a7dea9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f12e0aca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f12e0babf80 R15: 00007ffe5ee12a38
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 ee                	mov    %ebp,%esi
   2:	48 89 ef             	mov    %rbp,%rdi
   5:	e8 09 88 0e fd       	call   0xfd0e8813
   a:	4d 85 f6             	test   %r14,%r14
   d:	75 b5                	jne    0xffffffc4
   f:	e8 af 8d 0e fd       	call   0xfd0e8dc3
  14:	89 de                	mov    %ebx,%esi
  16:	4c 89 e7             	mov    %r12,%rdi
  19:	e8 35 68 6a fd       	call   0xfd6a6853
  1e:	0f 01 cb             	stac
  21:	48 89 d9             	mov    %rbx,%rcx
  24:	48 89 ef             	mov    %rbp,%rdi
  27:	4c 89 e6             	mov    %r12,%rsi
* 2a:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2c:	0f 1f 00             	nopl   (%rax)
  2f:	0f 01 ca             	clac
  32:	48 89 cb             	mov    %rcx,%rbx
  35:	eb 8d                	jmp    0xffffffc4
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)