syzbot


INFO: rcu detected stall in kcompactd (2)

Status: upstream: reported C repro on 2024/06/01 03:17
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+54594368fbd5a4f1754a@syzkaller.appspotmail.com
First crash: 182d, last: 29d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: fixed by (bisect log) [merge commit]:
commit 5ba202a7c986fc58dd2fd1571c99667ab2699995
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue Sep 17 10:40:34 2024 +0000

  Merge tag 'x86-build-2024-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] INFO: rcu detected stall in kcompactd (2) 2 (5) 2024/06/01 09:34
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in kcompactd mm 1 466d 466d 0/28 auto-obsoleted due to no activity on 2023/11/10 08:17
linux-6.1 INFO: rcu detected stall in kcompactd 1 162d 162d 0/3 auto-obsoleted due to no activity on 2024/09/19 19:09
upstream BUG: soft lockup in kcompactd kvm 1 1114d 1110d 0/28 auto-closed as invalid on 2022/01/31 12:36
Last patch testing requests (3)
Created Duration User Patch Repo Result
2024/06/11 18:32 23m retest repro upstream report log
2024/06/01 09:07 22m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master report log
2024/06/01 07:01 25m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master error
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2024/10/13 19:22 8h57m bisect fix upstream OK (1) job log
2024/09/13 12:03 2h57m bisect fix upstream OK (0) job log log
2024/08/14 00:35 5h44m bisect fix upstream OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=15837, q=1385054 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 8724 (4294964354-4294955630), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 8725 jiffies! g15837 f0x2 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:25856 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x18af/0x4bd0 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6782
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247
 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
 </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: 34 Comm: kcompactd1 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:55 [inline]
RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline]
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
RIP: 0010:unwind_next_frame+0xb49/0x22d0 arch/x86/kernel/unwind_orc.c:585
Code: 3e 03 00 00 83 fe 02 0f 85 98 04 00 00 48 89 6c 24 48 4c 89 7c 24 28 49 8d 6d 08 48 89 e8 48 c1 e8 03 48 89 84 24 88 00 00 00 <42> 80 3c 20 00 74 08 48 89 ef e8 c8 3b bd 00 48 89 6c 24 60 48 89
RSP: 0018:ffffc90000a17b10 EFLAGS: 00000a06
RAX: 1ffff92000142f7d RBX: 1ffffffff2252098 RCX: ffffffff9086f3d4
RDX: ffffffff912904c2 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc90000a17be8 R08: 0000000000000003 R09: ffffc90000a17cd0
R10: ffffc90000a17c30 R11: ffffffff818090c0 R12: dffffc0000000000
R13: ffffc90000a17be0 R14: ffffc90000a17c18 R15: ffffffff912904c6
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5379bf03ae CR3: 000000007ffc2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:2342 [inline]
 slab_free mm/slub.c:4579 [inline]
 kfree+0x1a0/0x440 mm/slub.c:4727
 skb_kfree_head net/core/skbuff.c:1086 [inline]
 skb_free_head net/core/skbuff.c:1098 [inline]
 skb_release_data+0x6a0/0x8a0 net/core/skbuff.c:1125
 skb_release_all net/core/skbuff.c:1190 [inline]
 __kfree_skb net/core/skbuff.c:1204 [inline]
 consume_skb+0x9f/0xf0 net/core/skbuff.c:1436
 nft_synproxy_eval_v4+0x3d2/0x610 net/netfilter/nft_synproxy.c:60
 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141
 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
 nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288
 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5666 [inline]
 __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5779
 process_backlog+0x662/0x15b0 net/core/dev.c:6111
 __napi_poll+0xcb/0x490 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6966
 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:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 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:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5202
Code: c9 50 e8 e9 00 0c 00 48 83 c4 08 4c 89 f7 e8 4d 39 00 00 e9 de 04 00 00 4c 89 f7 e8 80 df 6b 0a e8 eb 59 38 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90000aa77e8 EFLAGS: 00000282
RAX: 36fa67a1f605ea00 RBX: ffff8880202a9e00 RCX: ffffffff9a3d0903
RDX: dffffc0000000000 RSI: ffffffff8c0acb40 RDI: ffffffff8c6102a0
RBP: ffffc90000aa7830 R08: ffffffff901cfeef R09: 1ffffffff2039fdd
R10: dffffc0000000000 R11: fffffbfff2039fde R12: 1ffff110170e7f14
R13: dffffc0000000000 R14: ffff8880b863ea80 R15: ffff8880b873f8a0
 context_switch kernel/sched/core.c:5331 [inline]
 __schedule+0x18b7/0x4bd0 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6782
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615
 kcompactd+0x85a/0x1530 mm/compaction.c:3181
 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
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/23 04:08 upstream c2ee9f594da8 15fa2979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in kcompactd
2024/07/14 02:09 upstream d0d0cd380055 eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kcompactd
2024/05/28 17:14 upstream 2bfcfd584ff5 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kcompactd
2024/05/28 03:05 upstream 2bfcfd584ff5 f550015e .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in kcompactd
2024/05/23 01:00 linux-next 124cfbcd6d18 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in kcompactd
* Struck through repros no longer work on HEAD.