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INFO: rcu detected stall in kernfs_fop_write_iter (2)

Status: auto-obsoleted due to no activity on 2025/07/23 14:56
Subsystems: net mm
[Documentation on labels]
First crash: 256d, last: 96d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in kernfs_fop_write_iter 1 1 274d 274d 0/3 auto-obsoleted due to no activity on 2025/02/05 10:26
linux-6.1 INFO: rcu detected stall in kernfs_fop_write_iter (2) 1 2 357d 455d 0/3 auto-obsoleted due to no activity on 2024/11/14 04:13
upstream INFO: rcu detected stall in kernfs_fop_write_iter fs sctp 1 7 351d 446d 0/29 auto-obsoleted due to no activity on 2024/11/10 20:48
linux-6.1 INFO: rcu detected stall in kernfs_fop_write_iter 1 1 734d 734d 0/3 auto-obsoleted due to no activity on 2023/11/03 22:13
android-6-1 BUG: soft lockup in kernfs_fop_write_iter 1 1 77d 77d 0/2 premoderation: reported on 2025/05/13 05:43

Sample crash report:
bridge0: received packet on bridge_slave_0 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): P5197/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=10921, q=1004 ncpus=2)
task:udevd           state:R  running task     stack:24856 pid:5197  tgid:5197  ppid:1      task_flags:0x400140 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5891
Code: 0f c1 05 08 f3 0e 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 5d b5 0e 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc9000492f470 EFLAGS: 00000206
RAX: 3fd8ab6c8db08b00 RBX: ffffffff8e3bf5c0 RCX: ffffc9000492f47c
RDX: 0000000000000004 RSI: ffffffff8dbca2c7 RDI: ffffffff8bf465c0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000004 R11: 000000000004fc39 R12: ffffffff8169ed14
R13: 0000000000000206 R14: ffff88801bba2440 R15: 0000000000000005
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4161 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4217
 skb_clone+0x190/0x3f0 net/core/skbuff.c:2056
 do_one_broadcast net/netlink/af_netlink.c:1444 [inline]
 netlink_broadcast_filtered+0xb19/0xf10 net/netlink/af_netlink.c:1522
 netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1546
 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
 kobject_uevent_env+0xc6a/0x1870 lib/kobject_uevent.c:608
 kobject_synth_uevent+0x7d4/0x8a0 lib/kobject_uevent.c:207
 uevent_store+0x24/0x80 drivers/base/core.c:2750
 dev_attr_store+0x55/0x80 drivers/base/core.c:2440
 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x351/0x510 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x5ba/0x1180 fs/read_write.c:684
 ksys_write+0x12a/0x240 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc663516bf2
RSP: 002b:00007ffce728ea58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000056140ef0f6f0 RCX: 00007fc663516bf2
RDX: 0000000000000007 RSI: 000056140ef509c0 RDI: 000000000000000c
RBP: 0000000000000007 R08: 000056140ef509c0 R09: 0000000000000040
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000007
R13: 000056140ef509c0 R14: 00007ffce728ee38 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10331 jiffies! g10921 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:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 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: 0 Comm: swapper/0 Not tainted 6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:in_softirq_really kernel/kcov.c:171 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data+0x2b/0x90 kernel/kcov.c:246
Code: 89 d2 49 89 f8 49 89 f1 65 48 8b 15 97 96 eb 11 65 8b 05 a8 96 eb 11 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 0f 00 75 60 <a9> 00 00 f0 00 75 59 8b 82 3c 16 00 00 85 c0 74 4f 8b 82 18 16 00
RSP: 0018:ffffc90000007110 EFLAGS: 00000246
RAX: 0000000080000101 RBX: ffff8880a81f9500 RCX: ffffffff8a4c929c
RDX: ffffffff8e097740 RSI: 0000000000000081 RDI: 0000000000000003
RBP: ffff8880a81f8e10 R08: 0000000000000003 R09: 0000000000000081
R10: 000000000000dd86 R11: 0000000000000000 R12: 000000000000dd86
R13: ffff8880a81f95b4 R14: ffff8880a81f959c R15: ffff8880a81f957f
FS:  0000000000000000(0000) GS:ffff8881249b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f250dfd4ffc CR3: 0000000031160000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 vlan_proto net/bridge/br_netfilter_hooks.c:85 [inline]
 is_vlan_arp net/bridge/br_netfilter_hooks.c:111 [inline]
 br_nf_forward_finish+0x21c/0xba0 net/bridge/br_netfilter_hooks.c:642
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 br_nf_forward_ip.part.0+0x609/0x810 net/bridge/br_netfilter_hooks.c:719
 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:679 [inline]
 br_nf_forward+0xf0f/0x1be0 net/bridge/br_netfilter_hooks.c:776
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626
 nf_hook+0x45e/0x780 include/linux/netfilter.h:269
 NF_HOOK include/linux/netfilter.h:312 [inline]
 __br_forward+0x1be/0x5b0 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 br_flood+0x39c/0x650 net/bridge/br_forward.c:249
 br_handle_frame_finish+0xe8e/0x1c20 net/bridge/br_input.c:220
 br_nf_hook_thresh+0x301/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:282 [inline]
 br_handle_frame+0xad5/0x14a0 net/bridge/br_input.c:433
 __netif_receive_skb_core.constprop.0+0xa23/0x4a00 net/core/dev.c:5773
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5885
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6000
 process_backlog+0x442/0x15e0 net/core/dev.c:6352
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0xa97/0x1010 net/core/dev.c:7510
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81
Code: 25 5d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 3a 17 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007e10 EFLAGS: 000002c6
RAX: 0000000001561cad RBX: 0000000000000000 RCX: ffffffff8b72b419
RDX: 0000000000000000 RSI: ffffffff8dbef86e RDI: ffffffff8bf465c0
RBP: fffffbfff1c12ee8 R08: 0000000000000001 R09: ffffed10170865bd
R10: ffff8880b8432deb R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e097740 R14: ffffffff90864b10 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
 rest_init+0x16b/0x2b0 init/main.c:743
 start_kernel+0x3e9/0x4d0 init/main.c:1099
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x148
 </TASK>
net_ratelimit: 19249 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:1e:5d:b4:a5:71:f2, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:90:16:b1:44:2e, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 23187 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:da:90:16:b1:44:2e, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:1e:5d:b4:a5:71:f2, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/24 14:49 upstream a79be02bba5c 9c80ffa0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in kernfs_fop_write_iter
2025/04/01 21:27 upstream 08733088b566 b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in kernfs_fop_write_iter
2025/01/04 22:42 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kernfs_fop_write_iter
2024/11/15 04:29 upstream cfaaa7d010d1 f6ede3a3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kernfs_fop_write_iter
* Struck through repros no longer work on HEAD.