syzbot


INFO: rcu detected stall in ext4_file_write_iter

Status: upstream: reported C repro on 2019/04/20 13:09
Reported-by: syzbot+b0c07a7f1f6925ea6219@syzkaller.appspotmail.com
First crash: 1775d, last: 434d
Fix bisection: failed (error log, bisect log)
  
Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in ext4_file_write_iter 1 99d 99d 0/3 upstream: reported on 2023/11/21 20:44
upstream INFO: rcu detected stall in ext4_file_write_iter (3) block 5 933d 1022d 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 673d 674d 0/26 auto-closed as invalid on 2022/06/25 07:58
upstream INFO: rcu detected stall in ext4_file_write_iter (7) mm bpf ext4 3 181d 223d 23/26 fixed on 2023/10/12 12:47
upstream INFO: rcu detected stall in ext4_file_write_iter (4) mm C unreliable 58 769d 798d 0/26 closed as invalid on 2022/02/08 10:32
android-49 INFO: rcu detected stall in ext4_file_write_iter syz 2 1731d 1772d 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 1234d 1234d 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 374d 1783d 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 1296d 1828d 15/26 fixed on 2020/09/25 01:17
upstream INFO: rcu detected stall in ext4_file_write_iter (6) ext4 C error 8 322d 385d 22/26 fixed on 2023/06/08 14:41
linux-4.19 BUG: soft lockup in ext4_file_write_iter 1 979d 979d 0/1 auto-closed as invalid on 2021/10/22 22:26
Fix bisection attempts (24)
Created Duration User Patch Repo Result
2021/10/20 22:05 11m bisect fix linux-4.19.y error job log (0)
2021/09/20 21:36 28m bisect fix linux-4.19.y job log (0) log
2021/08/21 20:59 37m bisect fix linux-4.19.y job log (0) log
2021/07/22 20:30 28m bisect fix linux-4.19.y job log (0) log
2021/06/22 13:56 34m bisect fix linux-4.19.y job log (0) log
2021/05/23 04:46 38m bisect fix linux-4.19.y job log (0) log
2021/04/23 03:18 26m bisect fix linux-4.19.y job log (0) log
2021/03/23 22:56 25m bisect fix linux-4.19.y job log (0) log
2021/02/21 21:15 24m bisect fix linux-4.19.y job log (0) log
2021/02/18 09:56 19m bisect fix linux-4.19.y error job log (0)
2021/02/09 01:29 1m bisect fix linux-4.19.y error job log (0)
2021/01/10 01:03 26m bisect fix linux-4.19.y job log (0) log
2020/12/10 22:20 29m bisect fix linux-4.19.y job log (0) log
2020/11/10 21:49 26m bisect fix linux-4.19.y job log (0) log
2020/10/11 21:10 28m bisect fix linux-4.19.y job log (0) log
2020/09/11 20:38 31m bisect fix linux-4.19.y job log (0) log
2020/08/12 06:28 29m bisect fix linux-4.19.y job log (0) log
2020/07/13 06:00 27m bisect fix linux-4.19.y job log (0) log
2020/05/18 08:24 30m bisect fix linux-4.19.y job log (0) log
2020/04/03 07:36 27m bisect fix linux-4.19.y job log (0) log
2020/02/29 06:08 29m bisect fix linux-4.19.y job log (0) log
2020/01/30 05:39 29m bisect fix linux-4.19.y job log (0) log
2019/12/31 05:10 28m bisect fix linux-4.19.y job log (0) log
2019/12/01 04:43 27m bisect fix linux-4.19.y job log (0) log

Sample crash report:
hrtimer: interrupt took 69591 ns
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=4633, q=28)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295063364-4295052862), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor765 R  running task    27216  8117   8113 0x00000000
Call Trace:
 <IRQ>
 sched_show_task.cold+0x332/0x396 kernel/sched/core.c:5337
 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline]
 check_cpu_stall kernel/rcu/tree.c:1557 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0xb37/0xe19 kernel/rcu/tree.c:2682
 update_process_times+0x2a/0x70 kernel/time/timer.c:1650
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168
 tick_sched_timer+0xfc/0x290 kernel/time/tick-sched.c:1278
 __run_hrtimer kernel/time/hrtimer.c:1465 [inline]
 __hrtimer_run_queues+0x3f6/0xe60 kernel/time/hrtimer.c:1527
 hrtimer_interrupt+0x326/0x9e0 kernel/time/hrtimer.c:1585
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline]
 smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1096
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:101
Code: 90 90 90 90 90 90 90 90 48 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e 81 e2 00 01 1f 00 75 2b 8b 90 60 13 00 00 <83> fa 02 75 20 48 8b 88 68 13 00 00 8b 80 64 13 00 00 48 8b 11 48
RSP: 0018:ffff8880b02a7200 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff8880afa421c0 RBX: ffffea00021af840 RCX: ffffffff87eef3cc
RDX: 0000000000000000 RSI: ffffffff87eef3e3 RDI: 0000000000000007
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000007 R11: 0000000000000000 R12: ffffea00021af840
R13: ffff8880b1a27740 R14: dffffc0000000000 R15: 0000000000000000
 __radix_tree_lookup+0x1a3/0x370 lib/radix-tree.c:1054
 radix_tree_lookup_slot+0x70/0xc0 lib/radix-tree.c:1079
 find_get_entry+0x109/0x8a0 mm/filemap.c:1454
 pagecache_get_page+0x56/0xd50 mm/filemap.c:1564
 grab_cache_page_write_begin+0x6a/0xa0 mm/filemap.c:3120
 ext4_da_write_begin+0x2ba/0x10e0 fs/ext4/inode.c:3075
 generic_perform_write+0x1f8/0x4d0 mm/filemap.c:3170
 __generic_file_write_iter+0x24b/0x610 mm/filemap.c:3295
 ext4_file_write_iter+0x2fe/0xf20 fs/ext4/file.c:272
 call_write_iter include/linux/fs.h:1821 [inline]
 do_iter_readv_writev+0x668/0x790 fs/read_write.c:681
 do_iter_write+0x182/0x5d0 fs/read_write.c:960
 vfs_iter_write+0x70/0xa0 fs/read_write.c:973
 iter_file_splice_write+0x60d/0xbb0 fs/splice.c:750
 do_splice_from fs/splice.c:852 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1025
 splice_direct_to_actor+0x33f/0x8d0 fs/splice.c:980
 do_splice_direct+0x1a7/0x270 fs/splice.c:1068
 do_sendfile+0x550/0xc30 fs/read_write.c:1447
 __do_sys_sendfile64 fs/read_write.c:1502 [inline]
 __se_sys_sendfile64+0xc4/0x160 fs/read_write.c:1494
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f6d8dd06c59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff7bee0d38 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fff7bee0f18 RCX: 00007f6d8dd06c59
RDX: 00000000200001c0 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000200a198 R11: 0000000000000246 R12: 00007fff7bee0d6c
R13: 0000000000000000 R14: 00007fff7bee0d80 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10502 jiffies! g4633 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29208    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x4cf/0xfe0 kernel/time/timer.c:1818
 rcu_gp_kthread+0xdad/0x21c0 kernel/rcu/tree.c:2202
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/21 11:29 linux-4.19.y 3f8a27f9e27b d3e76707 .config console log report syz C [disk image] [vmlinux] ci2-linux-4-19 INFO: rcu detected stall in ext4_file_write_iter
2022/12/19 01:01 linux-4.19.y 3f8a27f9e27b 05494336 .config console log report syz C [disk image] [vmlinux] ci2-linux-4-19 INFO: rcu detected stall in ext4_file_write_iter
2019/06/22 12:57 linux-4.19.y 63bbbcd8ed53 34bf9440 .config console log report syz C ci2-linux-4-19
2020/06/13 06:00 linux-4.19.y 3fc898571b97 f4724dd3 .config console log report ci2-linux-4-19
2020/06/13 05:56 linux-4.19.y 3fc898571b97 f4724dd3 .config console log report ci2-linux-4-19
2020/04/18 08:09 linux-4.19.y 8488c3f3bc86 435c6d53 .config console log report ci2-linux-4-19
2020/03/04 06:43 linux-4.19.y a083db76118d 1f73b64b .config console log report ci2-linux-4-19
2019/06/13 12:01 linux-4.19.y 768292d05361 3f4e812b .config console log report ci2-linux-4-19
2019/04/20 12:08 linux-4.19.y c98875d930e9 b0e8efcb .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.