syzbot


INFO: task hung in xfs_ail_push_all_sync (3)

Status: upstream: reported C repro on 2024/12/02 13:43
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+92fbc8b664c9bbc40bf6@syzkaller.appspotmail.com
First crash: 583d, last: 33d
Cause bisection: introduced by (bisect log) :
commit 3eb96946f0be6bf447cbdf219aba22bc42672f92
Author: Christoph Hellwig <hch@lst.de>
Date: Wed May 24 06:05:38 2023 +0000

  block: make bio_check_eod work for zero sized devices

Crash: INFO: task hung in xfs_ail_push_all_sync (log)
Repro: C syz .config
  
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
31f3fd49-36a8-497e-b1b9-deb5433d9d61 assessment-security 💥 INFO: task hung in xfs_ail_push_all_sync (3) 2026/05/18 23:21 2026/05/18 23:21 2026/05/18 23:43 9f74d39908454b73546eaf1b8211b48b66e5c0fe failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/8e37c2cea5acd8382be47df570ccea47380440f4" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: ld.lld: error: undefined symbol: wcslen * * Restart config... * * * General architecture-dependent options * Kprobes (KPROBES) [N/y/?] n Optimize very unlikely/likely branches (JUMP_LABEL) [Y/n/?] y Static key selftest (STATIC_KEYS_SELFTEST) [N/y/?] n Static call selftest (STATIC_CALL_SELFTEST) [N/y/?] n Enable seccomp to safely execute untrusted bytecode (SECCOMP) [Y/n/?] y Show seccomp filter cache status in /proc/pid/seccomp_cache (SECCOMP_CACHE_DEBUG) [N/y/?] n Stack Protector buffer overflow detection (STACKPROTECTOR) [Y/n/?] y Strong Stack Protector (STACKPROTECTOR_STRONG) [Y/n/?] y Link Time Optimization (LTO) > 1. None (LTO_NONE) choice[1]: 1 Enable Clang's AutoFDO build (EXPERIMENTAL) (AUTOFDO_CLANG) [N/y/?] (NEW) Error in reading or end of file. Enable Clang's Propeller build (PROPELLER_CLANG) [N/y/?] (NEW) Error in reading or end of file. Use Clang's Control Flow Integrity (CFI) (CFI_CLANG) [N/y/?] (NEW) Error in reading or end of file. Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [28] 28 Number of bits to use for ASLR of mmap base address for compatible applications (ARCH_MMAP_RND_COMPAT_BITS) [8] 8 MMU page size > 1. 4KiB pages (PAGE_SIZE_4KB) choice[1]: 1 Provide system calls for 32-bit time_t (COMPAT_32BIT_TIME) [Y/n/?] y Use a virtually-mapped stack (VMAP_STACK) [Y/n/?] y Support for randomizing kernel stack offset on syscall entry (RANDOMIZE_KSTACK_OFFSET) [Y/n/?] y Default state of kernel stack offset randomization (RANDOMIZE_KSTACK_OFFSET_DEFAULT) [N/y/?] n Locking event counts collection (LOCK_EVENT_COUNTS) [N/y/?] n * * Memory initialization * Initialize kernel stack variables at function entry 1. no automatic stack variable initialization (weakest) (INIT_STACK_NONE) 2. pattern-init everything (strongest) (INIT_STACK_ALL_PATTERN) > 3. zero-init everything (strongest and safest) (INIT_STACK_ALL_ZERO) choice[1-3?]: 3 Enable heap memory zeroing on allocation by default (INIT_ON_ALLOC_DEFAULT_ON) [Y/n/?] y Enable heap memory zeroing on free by default (INIT_ON_FREE_DEFAULT_ON) [N/y/?] n Enable register zeroing on function exit (ZERO_CALL_USED_REGS) [N/y/?] (NEW) Error in reading or end of file. * * Kernel hardening options * Randomize layout of sensitive kernel structures > 1. Disable structure layout randomization (RANDSTRUCT_NONE) 2. Fully randomize structure layout (RANDSTRUCT_FULL) (NEW) choice[1-2?]: Error in reading or end of file. * * Compile-time checks and compiler options * Debug information 1. Disable debug information (DEBUG_INFO_NONE) 2. Rely on the toolchain's implicit default DWARF version (DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT) > 3. Generate DWARF Version 4 debuginfo (DEBUG_INFO_DWARF4) 4. Generate DWARF Version 5 debuginfo (DEBUG_INFO_DWARF5) choice[1-4?]: 3 Reduce debugging information (DEBUG_INFO_REDUCED) [N/y/?] n Compressed Debug information > 1. Don't compress debug information (DEBUG_INFO_COMPRESSED_NONE) 2. Compress debugging information with zlib (DEBUG_INFO_COMPRESSED_ZLIB) 3. Compress debugging information with zstd (DEBUG_INFO_COMPRESSED_ZSTD) (NEW) choice[1-3?]: Error in reading or end of file. Produce split debuginfo in .dwo files (DEBUG_INFO_SPLIT) [N/y/?] n Generate BTF type information (DEBUG_INFO_BTF) [N/y/?] n Provide GDB scripts for kernel debugging (GDB_SCRIPTS) [N/y/?] n Warn for stack frames larger than (FRAME_WARN) [2048] 2048 Strip assembler-generated symbols during link (STRIP_ASM_SYMS) [N/y/?] n Install uapi headers to usr/include (HEADERS_INSTALL) [N/y/?] n Make section mismatch errors non-fatal (SECTION_MISMATCH_WARN_ONLY) [Y/n/?] y Force all function address 64B aligned (DEBUG_FORCE_FUNCTION_ALIGN_64B) [N/y/?] n Generate vmlinux.map file when linking (VMLINUX_MAP) [N/y/?] n Force weak per-cpu definitions (DEBUG_FOR
Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly xfs report (Sep 2025) 0 (1) 2025/09/27 20:43
[syzbot] Monthly xfs report (Dec 2024) 0 (1) 2024/12/21 08:53
[syzbot] [xfs?] INFO: task hung in xfs_ail_push_all_sync (3) 0 (1) 2024/12/02 13:43
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in xfs_ail_push_all_sync xfs 1 syz 24 618d 614d 0/29 closed as invalid on 2024/09/22 23:15
upstream INFO: task hung in xfs_ail_push_all_sync (2) xfs 1 C 10 590d 588d 0/29 closed as invalid on 2024/10/17 00:53
Last patch testing requests (8)
Created Duration User Patch Repo Result
2026/04/25 03:07 32m retest repro linux-next report log
2026/02/13 11:49 20m retest repro linux-next report log
2025/12/05 07:36 42m retest repro linux-next report log
2025/09/26 04:09 20m retest repro linux-next report log
2025/07/17 18:57 1h01m retest repro linux-next report log
2025/05/08 16:03 2h05m retest repro linux-next report log
2025/02/27 15:07 9m retest repro linux-next error
2024/12/19 13:15 33m retest repro linux-next report log

Sample crash report:
INFO: task syz-executor901:5953 blocked for more than 143 seconds.
      Not tainted 6.12.0-next-20241128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor901 state:D stack:25656 pid:5953  tgid:5899  ppid:5854   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 xfs_ail_push_all_sync+0x236/0x310 fs/xfs/xfs_trans_ail.c:726
 xfs_log_quiesce+0xdf/0x5b0 fs/xfs/xfs_log.c:1018
 xfs_fs_freeze+0x8d/0x1a0 fs/xfs/xfs_super.c:940
 freeze_super+0x81b/0xee0 fs/super.c:2121
 fs_bdev_freeze+0x1ac/0x320 fs/super.c:1484
 bdev_freeze+0xd6/0x220 block/bdev.c:257
 xfs_fs_goingdown+0xa9/0x160 fs/xfs/xfs_fsops.c:442
 xfs_file_ioctl+0x1312/0x1b20 fs/xfs/xfs_ioctl.c:1360
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f417e96c189
RSP: 002b:00007f417e8f3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f417e9fc4b8 RCX: 00007f417e96c189
RDX: 0000000020000080 RSI: 000000008004587d RDI: 0000000000000004
RBP: 00007f417e9fc4b0 R08: 00007ffc4da61c37 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f417e9fc4bc
R13: 000000000000006e R14: 00007ffc4da61b50 R15: 00007ffc4da61c38
 </TASK>
INFO: task syz-executor901:5954 blocked for more than 143 seconds.
      Not tainted 6.12.0-next-20241128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor901 state:D stack:24688 pid:5954  tgid:5901  ppid:5852   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 xfs_ail_push_all_sync+0x236/0x310 fs/xfs/xfs_trans_ail.c:726
 xfs_log_quiesce+0xdf/0x5b0 fs/xfs/xfs_log.c:1018
 xfs_fs_freeze+0x8d/0x1a0 fs/xfs/xfs_super.c:940
 freeze_super+0x81b/0xee0 fs/super.c:2121
 fs_bdev_freeze+0x1ac/0x320 fs/super.c:1484
 bdev_freeze+0xd6/0x220 block/bdev.c:257
 xfs_fs_goingdown+0xa9/0x160 fs/xfs/xfs_fsops.c:442
 xfs_file_ioctl+0x1312/0x1b20 fs/xfs/xfs_ioctl.c:1360
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f417e96c189
RSP: 002b:00007f417e8f3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f417e9fc4b8 RCX: 00007f417e96c189
RDX: 0000000020000080 RSI: 000000008004587d RDI: 0000000000000004
RBP: 00007f417e9fc4b0 R08: 00007ffc4da61c37 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f417e9fc4bc
R13: 000000000000006e R14: 00007ffc4da61b50 R15: 00007ffc4da61c38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937b20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937b20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937b20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
1 lock held by klogd/5196:
 #0: ffff8880b873e8d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598
2 locks held by getty/5600:
 #0: ffff8880353b20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
5 locks held by syz-executor901/5953:
 #0: ffff888148c8ddb0 (&bdev->bd_fsfreeze_mutex){+.+.}-{4:4}, at: bdev_freeze+0x2a/0x220 block/bdev.c:248
 #1: ffff8880660c8420 (sb_writers#11){++++}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #1: ffff8880660c8420 (sb_writers#11){++++}-{0:0}, at: freeze_super+0x4e9/0xee0 fs/super.c:2099
 #2: ffff8880660c80e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #2: ffff8880660c80e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #2: ffff8880660c80e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: freeze_super+0x4f1/0xee0 fs/super.c:2100
 #3: ffff8880660c8518 (sb_pagefaults){+.+.}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #3: ffff8880660c8518 (sb_pagefaults){+.+.}-{0:0}, at: freeze_super+0x519/0xee0 fs/super.c:2104
 #4: ffff8880660c8610 (sb_internal#2){++++}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #4: ffff8880660c8610 (sb_internal#2){++++}-{0:0}, at: freeze_super+0x7cc/0xee0 fs/super.c:2118
5 locks held by syz-executor901/5954:
 #0: ffff888148c8c6b0 (&bdev->bd_fsfreeze_mutex){+.+.}-{4:4}, at: bdev_freeze+0x2a/0x220 block/bdev.c:248
 #1: ffff8880661e0420 (sb_writers#11){++++}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #1: ffff8880661e0420 (sb_writers#11){++++}-{0:0}, at: freeze_super+0x4e9/0xee0 fs/super.c:2099
 #2: ffff8880661e00e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #2: ffff8880661e00e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #2: ffff8880661e00e0 (&type->s_umount_key#45){+.+.}-{4:4}, at: freeze_super+0x4f1/0xee0 fs/super.c:2100
 #3: ffff8880661e0518 (sb_pagefaults){+.+.}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #3: ffff8880661e0518 (sb_pagefaults){+.+.}-{0:0}, at: freeze_super+0x519/0xee0 fs/super.c:2104
 #4: ffff8880661e0610 (sb_internal#2){++++}-{0:0}, at: sb_wait_write fs/super.c:1910 [inline]
 #4: ffff8880661e0610 (sb_internal#2){++++}-{0:0}, at: freeze_super+0x7cc/0xee0 fs/super.c:2118

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-next-20241128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xff6/0x1040 kernel/hung_task.c:397
 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>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3556 Comm: kworker/u8:10 Not tainted 6.12.0-next-20241128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:kasan_check_range+0x5/0x290 mm/kasan/generic.c:188
Code: 8e e8 ff 89 e1 ff 90 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 55 <41> 57 41 56 41 54 53 b0 01 48 85 f6 0f 84 a0 01 00 00 4c 8d 04 37
RSP: 0018:ffffc9000cac7760 EFLAGS: 00000046
RAX: 000000000000001d RBX: 0000000000000759 RCX: ffffffff817abd42
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff942c4968
RBP: 0000000000000000 R08: ffffffff942c4967 R09: 1ffffffff285892c
R10: dffffc0000000000 R11: fffffbfff285892d R12: 0000000000000001
R13: ffff8880323cc728 R14: 0000000000000001 R15: ffff8880323cc728
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cd011df600 CR3: 000000000e736000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 check_wait_context kernel/locking/lockdep.c:4875 [inline]
 __lock_acquire+0x8a2/0x2100 kernel/locking/lockdep.c:5176
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:754 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline]
 batadv_iv_ogm_schedule+0x43f/0x10a0 net/batman-adv/bat_iv_ogm.c:868
 batadv_iv_send_outstanding_bat_ogm_packet+0x6fe/0x810 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 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 (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/28 13:34 linux-next f486c8aa16b8 5df23865 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-linux-next-kasan-gce-root INFO: task hung in xfs_ail_push_all_sync
2024/12/05 11:19 upstream feffde684ac2 29f61fce .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/08 11:18 upstream 906bd684e4b1 179b040e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/07 23:01 upstream ff7afaeca1a1 867e44df .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/04 01:26 upstream a33ab3f94f51 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/03 22:25 upstream a33ab3f94f51 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/02 20:37 upstream 11066801dd4b f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/02 02:59 upstream 6c52d4da1c74 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/11/01 10:17 upstream 6c52d4da1c74 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in xfs_ail_push_all_sync
2024/11/01 07:34 upstream 6c52d4da1c74 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2024/10/22 16:10 upstream c2ee9f594da8 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in xfs_ail_push_all_sync
2025/03/29 09:49 linux-next e21edb1638e8 cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in xfs_ail_push_all_sync
2024/10/30 17:43 linux-next 86e3904dcdc7 66aeb999 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in xfs_ail_push_all_sync
* Struck through repros no longer work on HEAD.