syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-10323-g8f6a15f095a6 #0 Not tainted
------------------------------------------------------
klogd/4524 is trying to acquire lock:
ffff8880b9338ac0 (lock#9){+.+.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff8880b9338ac0 (lock#9){+.+.}-{2:2}, at: __mmap_lock_do_trace_acquire_returned+0x7f/0x790 mm/mmap_lock.c:237

but task is already holding lock:
ffff8880b933ec18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&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:1406 [inline]
       rq_lock kernel/sched/sched.h:1702 [inline]
       task_fork_fair+0x73/0x250 kernel/sched/fair.c:12710
       sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4844
       copy_process+0x439b/0x8f10 kernel/fork.c:2499
       kernel_clone+0xfd/0x980 kernel/fork.c:2797
       user_mode_thread+0xb4/0xf0 kernel/fork.c:2875
       rest_init+0x23/0x2b0 init/main.c:712
       start_kernel+0x3df/0x4c0 init/main.c:1103
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x148

-> #2 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:553 [inline]
       try_to_wake_up+0x9a/0x13e0 kernel/sched/core.c:4262
       signal_wake_up_state+0x79/0x120 kernel/signal.c:773
       signal_wake_up include/linux/sched/signal.h:448 [inline]
       complete_signal+0x465/0xc10 kernel/signal.c:1065
       __send_signal_locked+0x509/0x11c0 kernel/signal.c:1185
       do_notify_parent+0xeb4/0x1040 kernel/signal.c:2143
       exit_notify kernel/exit.c:753 [inline]
       do_exit+0x1369/0x2c10 kernel/exit.c:897
       do_group_exit+0xd3/0x2a0 kernel/exit.c:1026
       __do_sys_exit_group kernel/exit.c:1037 [inline]
       __se_sys_exit_group kernel/exit.c:1035 [inline]
       __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1035
       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 (&sighand->siglock){....}-{2:2}:
       __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_run+0x3e51/0xabd0 kernel/bpf/core.c:2012
       __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2253
       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+0x245/0x5a0 kernel/trace/bpf_trace.c:2446
       __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_lock include/linux/mmap_lock.h:145 [inline]
       process_vm_rw_single_vec mm/process_vm_access.c:105 [inline]
       process_vm_rw_core.constprop.0+0x7d7/0xa10 mm/process_vm_access.c:216
       process_vm_rw+0x301/0x360 mm/process_vm_access.c:284
       __do_sys_process_vm_readv mm/process_vm_access.c:296 [inline]
       __se_sys_process_vm_readv mm/process_vm_access.c:292 [inline]
       __x64_sys_process_vm_readv+0xe2/0x1c0 mm/process_vm_access.c:292
       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 (lock#9){+.+.}-{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
       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:164 [inline]
       stack_map_get_build_id_offset+0x5d9/0x7c0 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:1994 [inline]
       bpf_get_stack_raw_tp+0x124/0x160 kernel/trace/bpf_trace.c:1984
       ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:2012
       __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2253
       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+0x231/0x590 kernel/trace/bpf_trace.c:2444
       __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:5392 [inline]
       __schedule+0xd2b/0x5d00 kernel/sched/core.c:6745
       __schedule_loop kernel/sched/core.c:6822 [inline]
       schedule+0xe7/0x350 kernel/sched/core.c:6837
       syslog_print+0x214/0x5d0 kernel/printk/printk.c:1582
       do_syslog+0x3be/0x6a0 kernel/printk/printk.c:1734
       __do_sys_syslog kernel/printk/printk.c:1826 [inline]
       __se_sys_syslog kernel/printk/printk.c:1824 [inline]
       __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1824
       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:
  lock#9 --> &p->pi_lock --> &rq->__lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->__lock);
                               lock(&p->pi_lock);
                               lock(&rq->__lock);
  lock(lock#9);

 *** DEADLOCK ***

3 locks held by klogd/4524:
 #0: ffff8880b933ec18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
 #1: ffffffff8dbb1760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #1: ffffffff8dbb1760 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #1: ffffffff8dbb1760 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline]
 #1: ffffffff8dbb1760 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2444
 #2: ffff888015477398 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
 #2: ffff888015477398 (&mm->mmap_lock){++++}-{3:3}, at: stack_map_get_build_id_offset+0x1e8/0x7c0 kernel/bpf/stackmap.c:141

stack backtrace:
CPU: 1 PID: 4524 Comm: klogd Not tainted 6.9.0-syzkaller-10323-g8f6a15f095a6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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
 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:164 [inline]
 stack_map_get_build_id_offset+0x5d9/0x7c0 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:1994 [inline]
 bpf_get_stack_raw_tp+0x124/0x160 kernel/trace/bpf_trace.c:1984
 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:2012
 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2253
 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+0x231/0x590 kernel/trace/bpf_trace.c:2444
 __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:5392 [inline]
 __schedule+0xd2b/0x5d00 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6837
 syslog_print+0x214/0x5d0 kernel/printk/printk.c:1582
 do_syslog+0x3be/0x6a0 kernel/printk/printk.c:1734
 __do_sys_syslog kernel/printk/printk.c:1826 [inline]
 __se_sys_syslog kernel/printk/printk.c:1824 [inline]
 __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1824
 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: 0033:0x7f70c5278fa7
Code: Unable to access opcode bytes at 0x7f70c5278f7d.
RSP: 002b:00007ffcd7812ff8 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007f70c54174a0 RCX: 00007f70c5278fa7
RDX: 00000000000003ff RSI: 00007f70c54174a0 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000003 R09: 7abf98d885e43ab6
R10: 0000000000004000 R11: 0000000000000206 R12: 00007f70c54174a0
R13: 00007f70c5407212 R14: 00007f70c5417666 R15: 00007f70c5417666
 </TASK>