syzbot

 sign-in | mailing list | source | docs
🐞 Open [993] ≡ Subsystems 🐞 Fixed [5244] 🐞 Invalid [12518] ⬇ Missing Backports [83] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

INFO: rcu detected stall in ext4_file_write_iter (7)

Status: fixed on 2023/10/12 12:47
Subsystems: mm bpf ext4
[Documentation on labels]
Fix commit: 8c21ab1bae94 net/sched: fq_pie: avoid stalls in fq_pie_timer()
First crash: 282d, last: 239d
▶ ▼ Similar bugs (14)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in ext4_file_write_iter (8) mm 3 134d 189d 0/26 auto-obsoleted due to no activity on 2024/03/14 12:59
linux-5.15 INFO: rcu detected stall in ext4_file_write_iter 1 157d 157d 0/3 auto-obsoleted due to no activity on 2024/02/29 20:44
upstream INFO: rcu detected stall in ext4_file_write_iter (3) block 5 991d 1081d 0/26 auto-closed as invalid on 2021/11/07 19:52
upstream INFO: rcu detected stall in ext4_file_write_iter (5) mm 3 732d 732d 0/26 auto-closed as invalid on 2022/06/25 07:58
linux-6.1 INFO: rcu detected stall in ext4_file_write_iter 1 26d 26d 0/3 upstream: reported on 2024/04/01 06:27
upstream INFO: rcu detected stall in ext4_file_write_iter (4) mm C unreliable 58 827d 856d 0/26 closed as invalid on 2022/02/08 10:32
android-49 INFO: rcu detected stall in ext4_file_write_iter syz 2 1789d 1831d 0/3 public: reported syz repro on 2019/04/23 08:58
upstream INFO: rcu detected stall in ext4_file_write_iter (2) ext4 1 1293d 1293d 0/26 auto-closed as invalid on 2021/01/10 12:58
linux-4.14 INFO: rcu detected stall in ext4_file_write_iter C 7 432d 1841d 0/1 upstream: reported C repro on 2019/04/12 16:30
upstream INFO: rcu detected stall in ext4_file_write_iter C inconclusive done 93 1355d 1887d 15/26 fixed on 2020/09/25 01:17
linux-4.19 INFO: rcu detected stall in ext4_file_write_iter C error 9 493d 1834d 0/1 upstream: reported C repro on 2019/04/20 13:09
upstream INFO: rcu detected stall in ext4_file_write_iter (6) ext4 C error 8 381d 444d 22/26 fixed on 2023/06/08 14:41
linux-4.19 BUG: soft lockup in ext4_file_write_iter 1 1037d 1037d 0/1 auto-closed as invalid on 2021/10/22 22:26
android-5-15 BUG: soft lockup in ext4_file_write_iter 3 8d23h 20d 0/2 premoderation: reported on 2024/04/06 14:01

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=d3a4/1/0x4000000000000000 softirq=181359/181359 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=242989, q=170 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11939 Comm: syz-executor.5 Not tainted 6.5.0-syzkaller-08894-gb97d64c72259 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
RIP: 0010:rcu_is_watching+0x17/0xb0 kernel/rcu/tree.c:699
Code: ff ff e8 ec 2f 4f 09 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 e8 e4 8d 7e e8 bb 49 4f 09 89 c3 <83> f8 08 73 76 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 00 e9 ca
RSP: 0018:ffffc900001e0b40 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816cdf90
RDX: 0000000000000000 RSI: ffffffff8b596140 RDI: ffffffff8b596100
RBP: ffffc900001e0c90 R08: ffffffff8e99ae2f R09: 1ffffffff1d335c5
R10: dffffc0000000000 R11: fffffbfff1d335c6 R12: 1ffff9200003c178
R13: ffffffff817cb86b R14: ffffc900001e0cc0 R15: dffffc0000000000
FS:  00007f3cd8d536c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020010000 CR3: 000000004f435000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0xbf/0x9d0 kernel/locking/lockdep.c:5764
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194
 debug_hrtimer_deactivate kernel/time/hrtimer.c:427 [inline]
 debug_deactivate+0x1b/0x1f0 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1656 [inline]
 __hrtimer_run_queues+0x321/0xd10 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1063 [inline]
 __sysvec_apic_timer_interrupt+0x104/0x390 arch/x86/kernel/apic/apic.c:1080
 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1074
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:stack_trace_consume_entry+0x135/0x280 kernel/stacktrace.c:95
Code: 4c 89 ee 4c 89 f2 48 89 33 41 8b 19 41 0f b6 04 14 84 c0 0f 85 30 01 00 00 3b 5d 00 0f 92 c0 48 83 c4 18 5b 41 5c 41 5d 41 5e <41> 5f 5d c3 44 89 c9 80 e1 07 80 c1 03 38 c1 0f 8c ed fe ff ff 4c
RSP: 0018:ffffc9000392efa8 EFLAGS: 00000286
RAX: 0000000000000001 RBX: ffffffff81db374c RCX: ffff888089b0bb80
RDX: dffffc0000000000 RSI: ffffffff81db374c RDI: ffffc9000392f0ac
RBP: ffffc9000392f0a8 R08: 0000000000000001 R09: ffffc9000392f0b0
R10: 0000000000000003 R11: ffff888089b0bb80 R12: ffff888089b0bb80
R13: ffffffff817b1660 R14: ffffc9000392f0a0 R15: 1ffff92000725e16
 arch_stack_walk+0x13a/0x1a0 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x117/0x1c0 kernel/stacktrace.c:122
 save_stack+0xfa/0x1e0 mm/page_owner.c:128
 __set_page_owner+0x29/0x380 mm/page_owner.c:192
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x31ec/0x3370 mm/page_alloc.c:3183
 __alloc_pages+0x255/0x670 mm/page_alloc.c:4439
 folio_alloc+0x1e/0x60 mm/mempolicy.c:2308
 filemap_alloc_folio+0xde/0x500 mm/filemap.c:979
 __filemap_get_folio+0x431/0xbb0 mm/filemap.c:1939
 ext4_da_write_begin+0x5b5/0xa40 fs/ext4/inode.c:2883
 generic_perform_write+0x31b/0x630 mm/filemap.c:3945
 ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299
 ext4_file_write_iter+0x1df/0x1b10
 call_write_iter include/linux/fs.h:1985 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x782/0xaf0 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3cd807cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3cd8d530c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3cd819bf80 RCX: 00007f3cd807cae9
RDX: 000000000208e24b RSI: 0000000020003a80 RDI: 0000000000000003
RBP: 00007f3cd80c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3cd819bf80 R15: 00007ffd2c458b78
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g242989 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:26416 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1873/0x48f0 kernel/sched/core.c:6695
 schedule+0xc3/0x180 kernel/sched/core.c:6771
 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1613
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1812
 kthread+0x2b8/0x350 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 11944 Comm: syz-executor.5 Not tainted 6.5.0-syzkaller-08894-gb97d64c72259 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:csd_lock_wait kernel/smp.c:300 [inline]
RIP: 0010:smp_call_function_many_cond+0x1805/0x2890 kernel/smp.c:844
Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 64 38 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 9f 34 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 83 34
RSP: 0018:ffffc900042c7220 EFLAGS: 00000246
RAX: ffffffff81820f8d RBX: 1ffff1101732827d RCX: 0000000000040000
RDX: ffffc90024411000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900042c7420 R08: ffffffff81820f5c R09: 1ffffffff1d335c5
R10: dffffc0000000000 R11: fffffbfff1d335c6 R12: dffffc0000000000
R13: ffff8880b99413e8 R14: ffff8880b983d200 R15: 0000000000000001
FS:  00007f3cd8d326c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3cd8d32d58 CR3: 000000004f435000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1012
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:944 [inline]
 flush_tlb_mm_range+0x330/0x5c0 arch/x86/mm/tlb.c:1030
 tlb_flush arch/x86/include/asm/tlb.h:20 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:458 [inline]
 tlb_flush_mmu+0x1a6/0x4e0 mm/mmu_gather.c:299
 tlb_finish_mmu+0xd4/0x1f0 mm/mmu_gather.c:392
 unmap_region+0x300/0x350 mm/mmap.c:2318
 do_vmi_align_munmap+0x11c2/0x17f0 mm/mmap.c:2555
 do_vmi_munmap+0x24d/0x2d0 mm/mmap.c:2623
 mmap_region+0x72d/0x2280 mm/mmap.c:2673
 do_mmap+0x8ca/0xf80 mm/mmap.c:1354
 vm_mmap_pgoff+0x1db/0x410 mm/util.c:546
 ksys_mmap_pgoff+0x4ff/0x6d0 mm/mmap.c:1400
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3cd807cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3cd8d320c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f3cd819c050 RCX: 00007f3cd807cae9
RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007f3cd80c847a R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f3cd819c050 R15: 00007ffd2c458b78
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/31 16:28 upstream b97d64c72259 84803932 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in ext4_file_write_iter
2023/07/20 11:48 upstream bfa3037d8280 7b630fdb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in ext4_file_write_iter
2023/07/26 16:20 net d4a7ce642100 41fe1bae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in ext4_file_write_iter
* Struck through repros no longer work on HEAD.