INFO: task hung in anon_pipe_read (3)

Status: auto-obsoleted due to no activity on 2026/09/02 11:46
Subsystems: fs
Labels: prio:high
[Documentation on labels]
First crash: 115d, last: 108d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
72e45dd6 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: task hung in anon_pipe_read (3) 2026/05/29 23:52 2026/05/29 23:52 2026/05/30 01:09 6b4a8443
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in anon_pipe_read (2) fs 1 1 362d 362d 0/29 auto-obsoleted due to no activity on 2025/12/22 10:52
upstream INFO: task hung in anon_pipe_read fs 1 5 492d 492d 0/29 auto-obsoleted due to no activity on 2025/08/14 11:31

Sample crash report:
INFO: task syz-executor:4698 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:4698  tgid:4698  ppid:4697   task_flags:0x400100 flags:0x00000010
Call trace:
 __switch_to+0x2b0/0x6e0 arch/arm64/kernel/process.c:810 (T)
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1bec/0x2dcc kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x140/0x218 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x4e4/0xef8 kernel/locking/mutex.c:820
 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873
 anon_pipe_read+0x108/0xd14 fs/pipe.c:282
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x4ac/0x8e4 fs/read_write.c:574
 ksys_read+0x12c/0x224 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:724
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffff800088b672e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffff800088b672e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffff800088b672e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x4c/0x188 kernel/locking/lockdep.c:6775
2 locks held by getty/4493:
 #0: ffff0000c9e1c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009232e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x354/0xf84 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/4698:
 #0: ffff0000f1b05c60 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_read+0x108/0xd14 fs/pipe.c:282
2 locks held by syz.5.680/7751:
2 locks held by syz.5.680/7752:

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


Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/04 11:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ec7ef10b77a6 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in anon_pipe_read
2026/05/28 22:15 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 4b4362973b6f 9a5a7e5e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in anon_pipe_read
* Struck through repros no longer work on HEAD.