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INFO: task hung in fuse_set_nowrite

Status: auto-obsoleted due to no activity on 2026/01/11 04:59
Reported-by: syzbot+84cd4c0d453c564dda42@syzkaller.appspotmail.com
First crash: 266d, last: 251d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in fuse_set_nowrite 1 1 350d 350d 0/3 auto-obsoleted due to no activity on 2025/10/14 03:33
upstream INFO: task hung in fuse_set_nowrite (2) fuse 1 1 475d 475d 0/29 auto-obsoleted due to no activity on 2025/06/01 13:09
upstream INFO: task hung in fuse_set_nowrite fuse 1 1 646d 646d 0/29 auto-obsoleted due to no activity on 2024/12/12 21:26
linux-6.1 INFO: task hung in fuse_set_nowrite (2) 1 1 126d 126d 0/3 auto-obsoleted due to no activity on 2026/05/26 00:06

Sample crash report:
INFO: task syz.3.522:2121 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.522       state:D stack:0     pid:2121  tgid:2121  ppid:294    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 fuse_set_nowrite+0x1cd/0x310 fs/fuse/dir.c:2129
 fuse_sync_writes fs/fuse/file.c:528 [inline]
 fuse_flush+0x60f/0x1d50 fs/fuse/file.c:563
 filp_flush fs/open.c:1550 [inline]
 filp_close+0xc0/0x160 fs/open.c:1563
 __range_close fs/file.c:710 [inline]
 __close_range+0x50e/0x6c0 fs/file.c:767
 __do_sys_close_range fs/open.c:1616 [inline]
 __se_sys_close_range fs/open.c:1613 [inline]
 __x64_sys_close_range+0x7e/0x90 fs/open.c:1613
 x64_sys_call+0x1686/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:437
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f8f3698eec9
RSP: 002b:00007fff771d6078 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007f8f36be7da0 RCX: 00007f8f3698eec9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f8f36be7da0 R08: 000000000000024c R09: 0000001e771d636f
R10: 00007f8f36be7cb0 R11: 0000000000000246 R12: 000000000001362d
R13: 00007f8f36be5fa0 R14: ffffffffffffffff R15: 00007fff771d6190
 </TASK>
INFO: task syz.3.522:2129 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.522       state:D stack:0     pid:2129  tgid:2121  ppid:294    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 fuse_fsync+0x250/0x18f0 fs/fuse/file.c:641
 vfs_fsync_range+0x180/0x3a0 fs/sync.c:194
 generic_write_sync include/linux/fs.h:2894 [inline]
 generic_file_write_iter+0x30c/0x430 mm/filemap.c:4349
 fuse_cache_write_iter fs/fuse/file.c:1491 [inline]
 fuse_file_write_iter+0x1676/0x2650 fs/fuse/file.c:1842
 do_iter_readv_writev+0x628/0x810 fs/read_write.c:-1
 vfs_writev+0x485/0xcf0 fs/read_write.c:1076
 do_writev+0x14d/0x2d0 fs/read_write.c:1123
 __do_sys_writev fs/read_write.c:1196 [inline]
 __se_sys_writev fs/read_write.c:1193 [inline]
 __x64_sys_writev+0x81/0x90 fs/read_write.c:1193
 x64_sys_call+0x1fbb/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f8f3698eec9
RSP: 002b:00007f8f353d6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f8f36be6180 RCX: 00007f8f3698eec9
RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f8f36a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8f36be6218 R14: 00007f8f36be6180 R15: 00007fff771d5f18
 </TASK>
INFO: task syz.3.522:2133 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.522       state:D stack:0     pid:2133  tgid:2133  ppid:2121   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 fuse_flush+0x607/0x1d50 fs/fuse/file.c:562
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 1f5813a52420658c51670c32aa0b3f2b32c06bdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2ca/0x370 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: 284 Comm: syz-executor Not tainted syzkaller #0 1f5813a52420658c51670c32aa0b3f2b32c06bdf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x3b/0x90 kernel/kcov.c:314
Code: 00 eb 04 00 65 8b 0d ac e6 7e 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba ec 0b 00 00 00 74 52 8b 8a c8 0b 00 00 <83> f9 03 75 47 48 8b 8a d0 0b 00 00 44 8b 8a cc 0b 00 00 49 c1 e1
RSP: 0018:ffffc900011cf4a0 EFLAGS: 00000246
RAX: ffffffff8271fa37 RBX: ffff8881302c8938 RCX: 0000000000000000
RDX: ffff88810baa5f00 RSI: 0000000000000800 RDI: 0000000000000000
RBP: ffffc900011cf4a0 R08: ffff88810baa5f00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000180
R13: dffffc0000000000 R14: ffffc900011cf740 R15: 0000000000000800
FS:  0000555580ad8500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8b033b4198 CR3: 000000012af9c000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 avtab_search_node+0x57/0x560 security/selinux/ss/avtab.c:184
 context_struct_compute_av+0x587/0x1680 security/selinux/ss/services.c:656
 security_compute_av+0x38d/0xfa0 security/selinux/ss/services.c:1146
 avc_compute_av+0x89/0x770 security/selinux/avc.c:994
 avc_perm_nonode+0xc8/0x1b0 security/selinux/avc.c:1118
 avc_has_perm_noaudit+0x21c/0x360 security/selinux/avc.c:1161
 avc_has_perm+0xc2/0x220 security/selinux/avc.c:1196
 inode_has_perm security/selinux/hooks.c:1682 [inline]
 file_has_perm security/selinux/hooks.c:1772 [inline]
 selinux_revalidate_file_permission security/selinux/hooks.c:3626 [inline]
 selinux_file_permission+0x88b/0xb30 security/selinux/hooks.c:3647
 security_file_permission+0x4c/0xc0 security/security.c:2845
 rw_verify_area fs/read_write.c:471 [inline]
 vfs_read+0x1dc/0xc70 fs/read_write.c:561
 ksys_read+0x141/0x250 fs/read_write.c:713
 __do_sys_read fs/read_write.c:723 [inline]
 __se_sys_read fs/read_write.c:721 [inline]
 __x64_sys_read+0x7f/0x90 fs/read_write.c:721
 x64_sys_call+0x2638/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f0bcff8d89d
Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d c1 ac 22 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
RSP: 002b:00007ffd82b02f88 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0bcff8d89d
RDX: 0000000000000004 RSI: 00007ffd82b02f9c RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000037135d4e R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd82b033b0
R13: 0000000000000004 R14: 00007ffd82b02f9c R15: 00007ffd82b03030
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/13 04:58 android16-6.12 fbb5490cc8c3 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in fuse_set_nowrite
2025/09/28 07:56 android16-6.12 e34340c0d860 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in fuse_set_nowrite
* Struck through repros no longer work on HEAD.