INFO: task hung in do_get_write_access

Status: premoderation: reported syz repro on 2026/08/01 18:31
Reported-by: syzbot+4da23a43cfdc7fe08f5f@syzkaller.appspotmail.com
First crash: 6d09h, last: 1d08h
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_get_write_access (3) prio:low ext4 1 syz, C error 544 36m 622d 0/29 upstream: reported C repro on 2024/11/23 20:42
linux-6.1 INFO: task hung in do_get_write_access 1 syz, C 10 14h12m 3d03h 0/3 upstream: reported C repro on 2026/08/05 00:11
upstream INFO: task hung in do_get_write_access (2) ext4 1 1 808d 808d 0/29 auto-obsoleted due to no activity on 2024/08/19 05:35
upstream INFO: task hung in do_get_write_access ext4 1 1 1710d 1710d 0/29 closed as invalid on 2022/02/08 09:40
linux-6.6 INFO: task hung in do_get_write_access 1 syz, C 16 11h12m 3d05h 0/2 upstream: reported C repro on 2026/08/04 22:42
linux-5.15 INFO: task hung in do_get_write_access 1 syz, C 14 15h07m 3d04h 0/3 upstream: reported C repro on 2026/08/04 22:50

Sample crash report:
INFO: task kworker/u8:2:45 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:2    state:D stack:0     pid:45    tgid:45    ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 io_schedule+0x88/0xe0 kernel/sched/core.c:8786
 bit_wait_io+0x17/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xb3/0x2e0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x139/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x558/0xd70 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x268/0x3d0 fs/jbd2/transaction.c:1245
 __ext4_journal_get_write_access+0x1b6/0x6a0 fs/ext4/ext4_jbd2.c:239
 ext4_mb_mark_context+0x393/0xee0 fs/ext4/mballoc.c:4107
 ext4_mb_mark_diskspace_used+0x3aa/0x830 fs/ext4/mballoc.c:4223
 ext4_mb_new_blocks+0x840/0x36c0 fs/ext4/mballoc.c:6318
 ext4_ext_map_blocks+0x14d9/0x6080 fs/ext4/extents.c:4437
 ext4_map_create_blocks fs/ext4/inode.c:520 [inline]
 ext4_map_blocks+0x873/0x17f0 fs/ext4/inode.c:706
 mpage_map_one_extent fs/ext4/inode.c:2222 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2275 [inline]
 ext4_do_writepages+0x1c4a/0x39f0 fs/ext4/inode.c:2738
 ext4_writepages+0x28c/0x550 fs/ext4/inode.c:2827
 do_writepages+0x3d4/0x7f0 mm/page-writeback.c:2689
 __writeback_single_inode+0xc8/0xba0 fs/fs-writeback.c:1674
 writeback_sb_inodes+0x6a5/0xfb0 fs/fs-writeback.c:1970
 __writeback_inodes_wb+0x129/0x280 fs/fs-writeback.c:2041
 wb_writeback+0x3bb/0x850 fs/fs-writeback.c:2152
 wb_check_old_data_flush fs/fs-writeback.c:2256 [inline]
 wb_do_writeback fs/fs-writeback.c:2309 [inline]
 wb_workfn+0xa03/0xef0 fs/fs-writeback.c:2337
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task jbd2/sda1-8:73 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8     state:D stack:0     pid:73    tgid:73    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 io_schedule+0x88/0xe0 kernel/sched/core.c:8786
 bit_wait_io+0x17/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xb3/0x2e0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x139/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 __wait_on_buffer+0x5a/0x70 fs/buffer.c:123
 wait_on_buffer include/linux/buffer_head.h:422 [inline]
 jbd2_journal_commit_transaction+0x2dba/0x5510 fs/jbd2/commit.c:814
 kjournald2+0x386/0x6a0 fs/jbd2/journal.c:201
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task syz.2.19:398 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:0     pid:398   tgid:398   ppid:388    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6060 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7880
 __schedule_loop kernel/sched/core.c:7957 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7972
 io_schedule+0x88/0xe0 kernel/sched/core.c:8786
 bit_wait_io+0x17/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xb3/0x2e0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x139/0x190 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0x558/0xd70 fs/jbd2/transaction.c:1096
 jbd2_journal_get_write_access+0x268/0x3d0 fs/jbd2/transaction.c:1245
 __ext4_journal_get_write_access+0x1b6/0x6a0 fs/ext4/ext4_jbd2.c:239
 ext4_reserve_inode_write+0x1f6/0x2e0 fs/ext4/inode.c:5892
 __ext4_mark_inode_dirty+0xac/0x5e0 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xc9/0x110 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x251/0xc50 fs/fs-writeback.c:2515
 generic_update_time fs/inode.c:2056 [inline]
 inode_update_time fs/inode.c:2069 [inline]
 __file_update_time fs/inode.c:2258 [inline]
 file_update_time+0x1d3/0x210 fs/inode.c:2288
 ext4_page_mkwrite+0x2bf/0x1120 fs/ext4/inode.c:6221
 do_page_mkwrite mm/memory.c:3263 [inline]
 do_shared_fault mm/memory.c:5537 [inline]
 do_fault mm/memory.c:5599 [inline]
 do_pte_missing+0x12c1/0x4440 mm/memory.c:4069
 handle_pte_fault mm/memory.c:5940 [inline]
 __handle_mm_fault mm/memory.c:6083 [inline]
 handle_mm_fault+0x1189/0x1ba0 mm/memory.c:6251
 do_user_addr_fault+0x951/0x1230 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1479 [inline]
 exc_page_fault+0x58/0xc0 arch/x86/mm/fault.c:1534
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fb44c46b9e3
RSP: 002b:00007ffd06a79d80 EFLAGS: 00010246
RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b2cf24000 RSI: 0000000000040000 RDI: 00007fb44c7e0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffd06a7a010
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 200dea8a17c83f35b0a1e1238c384757fc17b797
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 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: 0 Comm: swapper/1 Not tainted syzkaller #0 200dea8a17c83f35b0a1e1238c384757fc17b797
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:update_rt_rq_load_avg+0x1f/0xc40 kernel/sched/pelt.c:370
Code: 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec a0 00 00 00 49 89 f4 <65> 48 8b 04 25 28 00 00 00 48 89 84 24 80 00 00 00 48 be 00 00 00
RSP: 0018:ffffc90000230ba0 EFLAGS: 00000086
RAX: 1ffff110206cd2ca RBX: ffff8881f6f4fa40 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff8881f6f4fa40 RDI: 0000003b62db6f87
RBP: ffffc90000230c78 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000046188 R12: ffff8881f6f4fa40
R13: dffffc0000000000 R14: 0000003b62db6f87 R15: ffff8881f6f50640
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2bc32aa000 CR3: 000000010d384000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 update_other_load_avgs+0xb7/0x100 kernel/sched/pelt.c:514
 __update_blocked_others kernel/sched/fair.c:10066 [inline]
 sched_balance_update_blocked_averages+0x131/0x12e0 kernel/sched/fair.c:10196
 update_nohz_stats kernel/sched/fair.c:12892 [inline]
 _nohz_idle_balance+0x317/0x5d0 kernel/sched/fair.c:12960
 nohz_idle_balance kernel/sched/fair.c:13017 [inline]
 sched_balance_softirq+0x8a/0x170 kernel/sched/fair.c:13247
 handle_softirqs+0x1aa/0x620 kernel/softirq.c:621
 __do_softirq kernel/softirq.c:659 [inline]
 invoke_softirq kernel/softirq.c:476 [inline]
 __irq_exit_rcu+0x47/0xb0 kernel/softirq.c:708
 irq_exit_rcu+0xd/0x30 kernel/softirq.c:720
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0x7f/0x90 arch/x86/kernel/smp.c:266
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x1f/0x30 arch/x86/include/asm/idtentry.h:709
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:116
Code: cc cc cc cc cc cc cc b8 da 1e 98 5e 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 a9 43 00 55 48 89 e5 fb f4 <5d> c3 cc cc cc cc cc cc cc cc cc cc cc b8 00 00 00 00 90 90 90 90
RSP: 0018:ffffc900001a7e00 EFLAGS: 000002c2
RAX: ffff8881f6f00000 RBX: ffff888103669300 RCX: ffffffff85a3b4fd
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000000866dc
RBP: ffffc900001a7e00 R08: ffff8881f6f395eb R09: 1ffff1103ede72bd
R10: dffffc0000000000 R11: ffffed103ede72be R12: 0000000000000000
R13: 1ffff110206cd260 R14: dffffc0000000000 R15: ffffffff87ecb868
 arch_safe_halt arch/x86/include/asm/paravirt.h:-1 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:754
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:791
 default_idle_call+0x3e/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:193 [inline]
 do_idle+0x1df/0x570 kernel/sched/idle.c:346
 cpu_startup_entry+0x47/0x60 kernel/sched/idle.c:445
 start_secondary+0x12e/0x140 arch/x86/kernel/smpboot.c:314
 common_startup_64+0x13b/0x157
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/01 18:30 android16-6.12 1a138e24e292 e611ffe1 .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in do_get_write_access
2026/08/06 19:33 android16-6.12 749a6f9d41aa c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in do_get_write_access
* Struck through repros no longer work on HEAD.