syzbot


INFO: task hung in bch2_readahead

Status: upstream: reported C repro on 2024/05/20 07:12
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+a6060114362257e9798a@syzkaller.appspotmail.com
First crash: 417d, last: 2h54m
Cause bisection: introduced by (bisect log) :
commit 1d16c605cc55ef26f0c65b362665a6c99080ccbc
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Thu Nov 9 19:22:46 2023 +0000

  bcachefs: Disk space accounting rewrite

Crash: INFO: task hung in __closure_sync (log)
Repro: C syz .config
  
Discussions (4)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] INFO: task hung in bch2_readahead 0 (3) 2024/12/28 17:09
[syzbot] Monthly bcachefs report (Aug 2024) 0 (1) 2024/08/13 08:53
[syzbot] Monthly bcachefs report (Jul 2024) 0 (1) 2024/07/12 12:53
[syzbot] Monthly bcachefs report (Jun 2024) 0 (1) 2024/06/11 08:27
Last patch testing requests (3)
Created Duration User Patch Repo Result
2025/06/05 06:36 14m retest repro upstream report log
2025/04/19 21:33 18m retest repro upstream report log
2025/02/05 14:14 1h14m retest repro upstream report log
Cause bisection attempts (2)
Created Duration User Patch Repo Result
2024/12/28 09:06 8h01m bisect upstream OK (1) job log log
2024/12/20 02:08 3h53m bisect upstream error job log

Sample crash report:
INFO: task syz-executor317:5861 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc3-syzkaller-00042-g78f4e737a53e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor317 state:D stack:15992 pid:5861  tgid:5859  ppid:5858   task_flags:0x440140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 __bch2_two_state_lock+0x1ea/0x370 fs/bcachefs/two_state_shared_lock.c:7
 bch2_two_state_lock fs/bcachefs/two_state_shared_lock.h:55 [inline]
 bch2_readahead+0x94f/0x1100 fs/bcachefs/fs-io-buffered.c:296
 read_pages+0x177/0x580 mm/readahead.c:160
 page_cache_ra_order+0xa24/0xc70 mm/readahead.c:515
 filemap_readahead mm/filemap.c:2571 [inline]
 filemap_get_pages+0xb22/0x1ea0 mm/filemap.c:2616
 filemap_splice_read+0x4fc/0xbc0 mm/filemap.c:2990
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x4a6/0xcc0 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0x181/0x270 fs/splice.c:1227
 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbef6878c19
RSP: 002b:00007fbef682d218 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fbef6906708 RCX: 00007fbef6878c19
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000006
RBP: 00007fbef6906700 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000e0000000 R11: 0000000000000246 R12: 00007fbef68d2b48
R13: 0000200000000040 R14: 0000200000000200 R15: 0700000000000000
 </TASK>
INFO: task syz-executor317:5873 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc3-syzkaller-00042-g78f4e737a53e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor317 state:D stack:23688 pid:5873  tgid:5859  ppid:5858   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 io_schedule+0x81/0xe0 kernel/sched/core.c:7723
 folio_wait_bit_common+0x6b0/0xb90 mm/filemap.c:1317
 folio_lock include/linux/pagemap.h:1114 [inline]
 bch2_mark_pagecache_unallocated+0x3a2/0x920 fs/bcachefs/fs-io-pagecache.c:275
 bch2_remap_file_range+0x92c/0xd10 fs/bcachefs/fs-io.c:933
 vfs_copy_file_range+0xd53/0x1310 fs/read_write.c:1591
 __do_sys_copy_file_range fs/read_write.c:1677 [inline]
 __se_sys_copy_file_range+0x2fb/0x470 fs/read_write.c:1644
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbef6878c19
RSP: 002b:00007fbef680c208 EFLAGS: 00000246 ORIG_RAX: 0000000000000146
RAX: ffffffffffffffda RBX: 00007fbef6906718 RCX: 00007fbef6878c19
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fbef6906710 R08: fffffbffa003e45b R09: 0700000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbef68d2b48
R13: 0000200000000040 R14: 0000200000000200 R15: 0700000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5591:
 #0: ffff88814c63b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor317/5861:
 #0: ffff888075f502e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline]
 #0: ffff888075f502e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: page_cache_ra_order+0x445/0xc70 mm/readahead.c:491
3 locks held by syz-executor317/5873:
 #0: ffff88823bf76428 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #0: ffff88823bf76428 (sb_writers#8){.+.+}-{0:0}, at: vfs_copy_file_range+0x916/0x1310 fs/read_write.c:1579
 #1: ffff888075f50148 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff888075f50148 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: lock_two_nondirectories+0xe7/0x180 fs/inode.c:1233
 #2: ffff888075f508e0 (&sb->s_type->i_mutex_key#14/4){+.+.}-{4:4}, at: bch2_remap_file_range+0x2b0/0xd10 fs/bcachefs/fs-io.c:906

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc3-syzkaller-00042-g78f4e737a53e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-rc3-syzkaller-00042-g78f4e737a53e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 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 e3 95 28 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c6
RAX: 7a0e49d0e75ae700 RBX: ffffffff81974c68 RCX: 7a0e49d0e75ae700
RDX: 0000000000000001 RSI: ffffffff8d96ea60 RDI: ffffffff8be1b9c0
RBP: ffffffff8de07ea8 R08: ffff8880b8632f5b R09: 1ffff110170c65eb
R10: dffffc0000000000 R11: ffffed10170c65ec R12: ffffffff8f9fe1f0
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a50
FS:  0000000000000000(0000) GS:ffff888125c83000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559e8db2f168 CR3: 000000000df38000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:749
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:745
 start_kernel+0x47d/0x500 init/main.c:1102
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (328):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/24 08:35 upstream 78f4e737a53e e2f27c35 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/04/21 07:04 upstream 6fea5fabd332 2a20f901 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs INFO: task hung in bch2_readahead
2024/12/19 10:24 upstream eabcdba3ad40 1432fc84 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/27 09:57 upstream f02769e7f272 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/26 00:28 upstream 92ca6c498a5e 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/06/25 05:12 upstream 7595b66ae9de 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/22 23:51 upstream b67ec639010f d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/20 21:55 upstream 41687a5c6f8b 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/18 05:14 upstream 4663747812d1 e77fae15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/16 23:07 upstream e04c78d86a96 d1716036 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/06/15 22:06 upstream 08215f5486ec 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/06/15 15:13 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/05/22 06:31 upstream d608703fcdd9 0919b50b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/05/17 15:26 upstream 172a9d94339c f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/14 18:42 upstream 1a80a098c606 a4fa04ef .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/09 15:00 upstream 9c69f8884904 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/09 03:42 upstream 2c89c1b655c0 bb813bcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/05 07:43 upstream 14c55b7bb0a8 b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/04 17:28 upstream e8ab83e34bdc b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/03 03:35 upstream 2bfcee565c3a b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/05/01 22:16 upstream 4f79eaa2ceac 51b137cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/04/29 14:18 upstream ca91b9500108 aeb6ec69 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_readahead
2025/04/25 20:52 upstream 02ddfb981de8 c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/04/21 16:30 upstream 9d7a0577c9db 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/04/21 02:58 upstream 6fea5fabd332 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/04/05 18:32 upstream a8662bcd2ff1 c53ea9c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/26 22:47 upstream 2df0c02dab82 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/24 18:41 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/23 04:25 upstream 183601b78a9b 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/22 20:03 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/22 13:19 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/21 23:43 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/16 11:19 upstream 31d7109a19f6 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/15 15:52 upstream a29967be967e e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/15 04:44 upstream a29967be967e e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/14 17:31 upstream 695caca9345a e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/13 11:06 upstream b7f94fcf5546 44be8b44 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/08 02:07 upstream 00a7d39898c8 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/07 21:36 upstream 00a7d39898c8 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/05 13:43 upstream 48a5eed9ad58 60f5d8d9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/02 16:56 upstream ece144f151ac c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/02 03:32 upstream 03d38806a902 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/03/01 13:30 upstream 7a5668899f54 67cf5345 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/24 20:37 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/24 01:16 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/21 10:18 upstream 334426094588 0808a665 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/20 23:50 upstream e9a8cac0bf89 0808a665 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/18 23:52 upstream 6537cfb395f3 9a14138f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/11 22:49 upstream 09fbf3d50205 f2baddf5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/08 13:29 upstream 8f6629c004b1 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/07 14:41 upstream bb066fe812d6 53657d1b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2025/02/07 10:42 upstream bb066fe812d6 53657d1b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2024/06/11 14:10 upstream 83a7eefedc9b c7d7d815 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in bch2_readahead
2024/06/09 09:21 upstream 771ed66105de 82c05ab8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in bch2_readahead
2024/05/16 13:15 upstream 8c06da67d0bd ef5d53ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2024/05/16 07:05 upstream 8c06da67d0bd ef5d53ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2024/05/05 14:07 upstream 7367539ad4b0 610f2a54 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_readahead
2024/05/12 06:55 linux-next 75fa778d74b7 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in bch2_readahead
2024/09/24 16:35 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5f5673607153 5643e0e9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in bch2_readahead
* Struck through repros no longer work on HEAD.