syzbot
INFO: rcu detected stall in rw_verify_area (4)
Status: auto-obsoleted due to no activity on 2026/09/28 09:12
Subsystems:
apparmor
Labels:
prio:high
[Documentation on labels]
First crash: 94d, last: 94d
Sample crash report:
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6712/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=202337, q=2494 ncpus=2)
task:syz-executor state:R running task stack:28120 pid:6712 tgid:6712 ppid:30468 task_flags:0x400040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5945
Code: 1a 00 00 b8 ff ff ff ff 65 0f c1 05 b4 2c 8c 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 90 0f 0b 90 48 c7
RSP: 0018:ffffc9000cecf9c8 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000046
RDX: ffff8880256abe00 RSI: ffffffff8e25a5ea RDI: ffffffff8c2a9f80
RBP: 00000000ffffffff R08: ffffffff84750efb R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e959c20 R12: 0000000000000246
R13: ffff8880256abe00 R14: ffffffff8e959c20 R15: 0000000000000000
aa_file_perm+0x26b/0x15f0 security/apparmor/file.c:638
common_file_perm security/apparmor/lsm.c:530 [inline]
apparmor_file_permission+0x14d/0x300 security/apparmor/lsm.c:543
security_file_permission+0x8d/0x260 security/security.c:2392
rw_verify_area+0xbb/0x4c0 fs/read_write.c:475
vfs_read+0x165/0xa80 fs/read_write.c:565
ksys_read+0x150/0x270 fs/read_write.c:716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd2655d68e
RSP: 002b:00007ffc5879af78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000555576fba500 RCX: 00007fdd2655d68e
RDX: 00000000000003e8 RSI: 00007ffc5879afe0 RDI: 00000000000000c8
RBP: 00007ffc5879b41c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000001bf
R13: 0000555576fcda00 R14: 00000000000faa4c R15: 00007ffc5879b470
</TASK>
rcu: rcu_preempt kthread starved for 932 jiffies! g202337 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5361 Comm: crond Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:98 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline]
RIP: 0010:kasan_check_range+0x97/0x2c0 mm/kasan/generic.c:200
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 9e 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00 00 44 89 dd
RSP: 0018:ffffc90000006de8 EFLAGS: 00000246
RAX: ffffc90003627e01 RBX: fffffffffffffffe RCX: ffffffff8176fe94
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90000006f38
RBP: 0000000000000000 R08: ffffc90000006f47 R09: 1ffff92000000de8
R10: dffffc0000000000 R11: fffff52000000de7 R12: 0000000000000002
R13: ffffffff90d7df4c R14: fffff52000000de9 R15: 1ffff92000000de7
FS: 00007f0006202c80(0000) GS:ffff888125226000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5be1da54e8 CR3: 0000000077128000 CR4: 00000000003526f0
Call Trace:
<IRQ>
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
unwind_next_frame+0xd04/0x2550 arch/x86/kernel/unwind_orc.c:621
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4612 [inline]
slab_alloc_node mm/slub.c:4945 [inline]
kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4959
skb_clone+0x212/0x3a0 net/core/skbuff.c:2110
deliver_clone net/bridge/br_forward.c:125 [inline]
br_flood+0x616/0x8d0 net/bridge/br_forward.c:257
br_handle_frame_finish+0x1175/0x1990 net/bridge/br_input.c:229
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442
__netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093
__netif_receive_skb_one_core net/core/dev.c:6204 [inline]
__netif_receive_skb net/core/dev.c:6319 [inline]
process_backlog+0x706/0x1860 net/core/dev.c:6670
__napi_poll+0xaa/0x330 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:7949
handle_softirqs+0x225/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:kasan_check_range+0x0/0x2c0 mm/kasan/generic.c:199
Code: fe 90 0f 0b 48 89 df 48 c7 c6 92 c0 25 8e e8 67 23 f4 fe 90 0f 0b cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <0f> 1f 40 d6 55 41 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 ae
RSP: 0018:ffffc90003627718 EFLAGS: 00000246
RAX: ffffc90003627f48 RBX: 0000000000000010 RCX: ffffffff8176fe94
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90003627838
RBP: 0000000000000000 R08: ffffc90003627f48 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e959c20 R12: dffffc0000000000
R13: ffffffff91702e5e R14: ffffc90003627838 R15: ffffc90003627830
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
unwind_next_frame+0xd04/0x2550 arch/x86/kernel/unwind_orc.c:621
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950
__slab_free+0x274/0x2c0 mm/slub.c:5767
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4612 [inline]
slab_alloc_node mm/slub.c:4945 [inline]
kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4959
alloc_filename fs/namei.c:147 [inline]
do_getname+0x2e/0x250 fs/namei.c:187
getname include/linux/fs.h:2532 [inline]
getname_maybe_null include/linux/fs.h:2539 [inline]
class_filename_maybe_null_constructor include/linux/fs.h:2563 [inline]
vfs_fstatat+0x45/0x170 fs/stat.c:368
__do_sys_newfstatat fs/stat.c:538 [inline]
__se_sys_newfstatat fs/stat.c:532 [inline]
__x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f00063bcb0a
Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
RSP: 002b:00007ffd78a3bbd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007f000656c490 RCX: 00007f00063bcb0a
RDX: 00007ffd78a3bbf8 RSI: 00007f00065457e8 RDI: 00000000ffffff9c
RBP: 000000006a438770 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000003c R14: 0000000000000000 R15: 000000000000002d
</TASK>
net_ratelimit: 10788 callbacks suppressed
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c2:7a:81:37:50:ec, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c2:7a:81:37:50:ec, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
net_ratelimit: 15402 callbacks suppressed
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c2:7a:81:37:50:ec, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c2:7a:81:37:50:ec, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
* Struck through repros no longer work on HEAD.