syzbot

======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-10555-gbcd28cfd04eb #0 Not tainted
------------------------------------------------------
syz-executor207/5227 is trying to acquire lock:
ffff8880b8629430 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
ffff8880b8629430 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
ffff8880b8629430 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810

but task is already holding lock:
ffff8880b862a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&base->lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
       __mod_timer+0x1ca/0xeb0 kernel/time/timer.c:1132
       queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2552
       kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3838
       pwq_release_workfn+0x664/0x800 kernel/workqueue.c:5078
       kthread_worker_fn+0x500/0xb70 kernel/kthread.c:842
       kthread+0x2f0/0x390 kernel/kthread.c:389
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (krc.lock){..-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
       kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810
       trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540
       bpf_prog_4febba1e7eaf042b+0x4b/0x54
       bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
       __bpf_prog_run include/linux/filter.h:701 [inline]
       bpf_prog_run include/linux/filter.h:708 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
       bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359
       trace_timer_start include/trace/events/timer.h:52 [inline]
       enqueue_timer+0x3ce/0x570 kernel/time/timer.c:663
       internal_add_timer kernel/time/timer.c:688 [inline]
       __mod_timer+0xa0e/0xeb0 kernel/time/timer.c:1183
       dsp_cmx_send+0x21bf/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1839
       call_timer_fn+0x18e/0x650 kernel/time/timer.c:1794
       expire_timers kernel/time/timer.c:1845 [inline]
       __run_timers kernel/time/timer.c:2419 [inline]
       __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
       run_timer_base kernel/time/timer.c:2439 [inline]
       run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
       handle_softirqs+0x2c5/0x980 kernel/softirq.c:554
       __do_softirq kernel/softirq.c:588 [inline]
       invoke_softirq kernel/softirq.c:428 [inline]
       __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
       irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
       instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
       sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037
       asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
       lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5826
       rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
       rcu_read_lock include/linux/rcupdate.h:849 [inline]
       __pte_offset_map+0x9e/0x380 mm/pgtable-generic.c:287
       pte_offset_map_nolock+0xad/0x1f0 mm/pgtable-generic.c:314
       handle_pte_fault+0x1b5/0x6800 mm/memory.c:5737
       __handle_mm_fault mm/memory.c:5894 [inline]
       handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6062
       do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&base->lock);
                               lock(krc.lock);
                               lock(&base->lock);
  lock(krc.lock);

 *** DEADLOCK ***

6 locks held by syz-executor207/5227:
 #0: ffff888024c67df0 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
 #0: ffff888024c67df0 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x34b/0x790 mm/memory.c:6228
 #1: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #1: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: __pte_offset_map+0x82/0x380 mm/pgtable-generic.c:287
 #2: ffffc90000007c00 ((&dsp_spl_tl)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1791
 #3: ffffffff8fa01478 (dsp_lock){..-.}-{2:2}, at: dsp_cmx_send+0x26/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1632
 #4: ffff8880b862a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
 #5: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #5: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #5: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2317 [inline]
 #5: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2359

stack backtrace:
CPU: 0 UID: 0 PID: 5227 Comm: syz-executor207 Not tainted 6.11.0-syzkaller-10555-gbcd28cfd04eb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
 add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
 kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810
 trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540
 bpf_prog_4febba1e7eaf042b+0x4b/0x54
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359
 trace_timer_start include/trace/events/timer.h:52 [inline]
 enqueue_timer+0x3ce/0x570 kernel/time/timer.c:663
 internal_add_timer kernel/time/timer.c:688 [inline]
 __mod_timer+0xa0e/0xeb0 kernel/time/timer.c:1183
 dsp_cmx_send+0x21bf/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1839
 call_timer_fn+0x18e/0x650 kernel/time/timer.c:1794
 expire_timers kernel/time/timer.c:1845 [inline]
 __run_timers kernel/time/timer.c:2419 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
 run_timer_base kernel/time/timer.c:2439 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5826
Code: 2b 00 74 08 4c 89 f7 e8 0a 4d 8e 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0000:ffffc90002f2f6a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005e5ee0 RCX: 44cd3a51c77b4d00
RDX: dffffc0000000000 RSI: ffffffff8c0adbc0 RDI: ffffffff8c6100a0
RBP: ffffc90002f2f7e8 R08: ffffffff942687c7 R09: 1ffffffff284d0f8
R10: dffffc0000000000 R11: fffffbfff284d0f9 R12: 1ffff920005e5edc
R13: dffffc0000000000 R14: ffffc90002f2f700 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 __pte_offset_map+0x9e/0x380 mm/pgtable-generic.c:287
 pte_offset_map_nolock+0xad/0x1f0 mm/pgtable-generic.c:314
 handle_pte_fault+0x1b5/0x6800 mm/memory.c:5737
 __handle_mm_fault mm/memory.c:5894 [inline]
 handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6062
 do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fa7b8d341f8
Code: Unable to access opcode bytes at 0x7fa7b8d341ce.
RSP: 002b:00007ffcb673a298 EFLAGS: 00010206
RAX: 00007fa7b8d64ad8 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 00007fa7b8d65d00 RSI: 0000000000000000 RDI: 00007fa7b8d64ad8
RBP: 00007fa7b8d63120 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa7b8d65ce8
R13: 0000000000000000 R14: 00007fa7b8d65d00 R15: 00007fa7b8cbb1f0
 </TASK>
----------------
Code disassembly (best guess):
   0:	2b 00                	sub    (%rax),%eax
   2:	74 08                	je     0xc
   4:	4c 89 f7             	mov    %r14,%rdi
   7:	e8 0a 4d 8e 00       	call   0x8e4d16
   c:	f6 44 24 61 02       	testb  $0x2,0x61(%rsp)
  11:	0f 85 85 01 00 00    	jne    0x19c
  17:	41 f7 c7 00 02 00 00 	test   $0x200,%r15d
  1e:	74 01                	je     0x21
  20:	fb                   	sti
  21:	48 c7 44 24 40 0e 36 	movq   $0x45e0360e,0x40(%rsp)
  28:	e0 45
* 2a:	4b c7 44 25 00 00 00 	movq   $0x0,0x0(%r13,%r12,1) <-- trapping instruction
  31:	00 00
  33:	43 c7 44 25 09 00 00 	movl   $0x0,0x9(%r13,%r12,1)
  3a:	00 00
  3c:	43                   	rex.XB
  3d:	c7                   	.byte 0xc7
  3e:	44                   	rex.R
  3f:	25                   	.byte 0x25