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INFO: rcu detected stall in proc_reg_read_iter (2)

Status: auto-obsoleted due to no activity on 2025/11/28 17:40
Subsystems: mm
[Documentation on labels]
First crash: 100d, last: 100d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in proc_reg_read_iter fs 1 1 725d 725d 0/29 auto-obsoleted due to no activity on 2024/03/13 15:35
linux-5.15 INFO: rcu detected stall in proc_reg_read_iter 1 1 164d 164d 0/3 auto-obsoleted due to no activity on 2025/10/05 00:54

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:86:c8:80:4c:8f:3b, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7051/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=17477, q=1112 ncpus=2)
task:syz.3.246       state:R  running task     stack:28872 pid:7051  tgid:7050  ppid:5873   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__sanitizer_cov_trace_pc+0x56/0x70 kernel/kcov.c:222
Code: 00 f0 00 75 35 8b 82 3c 16 00 00 85 c0 74 2b 8b 82 18 16 00 00 83 f8 02 75 20 48 8b 8a 20 16 00 00 8b 92 1c 16 00 00 48 8b 01 <48> 83 c0 01 48 39 d0 73 07 48 89 01 48 89 34 c1 e9 95 c7 d8 09 0f
RSP: 0018:ffffc900190379e8 EFLAGS: 00000246
RAX: 000000000007ffff RBX: 000000000002b2d1 RCX: ffffc9000c945000
RDX: 0000000000080000 RSI: ffffffff822aa65c RDI: 0000000000000005
RBP: 000000000002b400 R08: 0000000000000005 R09: 0000000000000018
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88801d0fe150
R13: fffffbfff1bea08e R14: 0000000000000cc0 R15: dffffc0000000000
 gfp_migratetype include/linux/gfp.h:28 [inline]
 pagetypeinfo_showmixedcount_print+0x5dc/0x8c0 mm/page_owner.c:472
 walk_zones_in_node mm/vmstat.c:1547 [inline]
 pagetypeinfo_showmixedcount mm/vmstat.c:1704 [inline]
 pagetypeinfo_show+0x876/0xa70 mm/vmstat.c:1726
 seq_read_iter+0x509/0x12c0 fs/seq_file.c:230
 proc_reg_read_iter+0x21d/0x310 fs/proc/inode.c:299
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x8bc/0xcf0 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f693ab8ebe9
RSP: 002b:00007f693ba4b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f693adc5fa0 RCX: 00007f693ab8ebe9
RDX: 00000000000000be RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f693ac11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f693adc6038 R14: 00007f693adc5fa0 R15: 00007fffaf63e328
 </TASK>
rcu: rcu_preempt kthread starved for 3737 jiffies! g17477 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27368 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1304 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:239 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4855 [inline]
RIP: 0010:__lock_acquire+0x22a/0x1ce0 kernel/locking/lockdep.c:5187
Code: 09 d0 41 89 44 24 20 8b 84 24 c0 00 00 00 41 89 44 24 24 e8 a8 b0 ff ff 44 0f b6 b0 c4 00 00 00 41 0f b7 44 24 20 66 25 ff 1f <0f> b7 c0 48 0f a3 05 5b 88 45 14 0f 83 1d 05 00 00 48 8d 04 80 48
RSP: 0018:ffffc90000a080f0 EFLAGS: 00000002
RAX: 0000000000000007 RBX: ffff888028b946f0 RCX: 0000000000020000
RDX: 0000000000000007 RSI: 0000000000000001 RDI: ffff888028b94718
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000028 R11: 0000000000000001 R12: ffff888028b94718
R13: ffff888028b93c00 R14: 0000000000000003 R15: ffffffff8e5c10a0
FS:  0000000000000000(0000) GS:ffff8881247c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5aeb4f56c0 CR3: 00000000764da000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 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:330 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236
 __skb_ext_alloc+0x1a/0x80 net/core/skbuff.c:6976
 skb_ext_add+0x232/0x7a0 net/core/skbuff.c:7079
 nf_bridge_alloc include/net/netfilter/br_netfilter.h:12 [inline]
 br_nf_pre_routing_ipv6+0xca/0x8c0 net/bridge/br_netfilter_ipv6.c:172
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0xad8/0x14b0 net/bridge/br_input.c:434
 __netif_receive_skb_core.constprop.0+0xa25/0x48c0 net/core/dev.c:5878
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5989
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6104
 process_backlog+0x442/0x15e0 net/core/dev.c:6456
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7506
 napi_poll net/core/dev.c:7569 [inline]
 net_rx_action+0xa9f/0xfe0 net/core/dev.c:7696
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 do_softirq kernel/softirq.c:480 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:467
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:407
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:910 [inline]
 __dev_queue_xmit+0xb06/0x4490 net/core/dev.c:4752
 dev_queue_xmit include/linux/netdevice.h:3361 [inline]
 tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
 kthread+0x1e1/0x3e0 drivers/block/aoe/aoecmd.c:1241
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 12344 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 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 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:86:c8:80:4c:8f:3b, 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:86:c8:80:4c:8f:3b, vlan:0)
net_ratelimit: 13887 callbacks suppressed
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 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ea:14:d6:7f:81:60, 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ea:14:d6:7f:81:60, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/30 17:32 upstream 11e7861d680c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in proc_reg_read_iter
* Struck through repros no longer work on HEAD.