ci starts bisection 2026-01-06 11:55:51.525570519 +0000 UTC m=+3542141.051056639
bisecting fixing commit since 05df91921da664ebba2752a7e45b63e3dddb85de
building syzkaller on 4f67c4aece4f5794be20c6bc99c177e44b1320e8
ensuring issue is reproducible on original commit 05df91921da664ebba2752a7e45b63e3dddb85de
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: d23acc0825ebb61894bf6af073d899dd3813a8163495746555ccccdd2e0f5893
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
check whether we can drop unnecessary instrumentation
disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep memleak], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: cd09676d11a638b1feee9308d1f80c0c92ba0f802d278784ed674beaaba4476b
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the bug reproduces without the instrumentation
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
kconfig minimization: base=4109 full=8470 leaves diff=2199
split chunks (needed=false): <2199>
split chunk #0 of len 2199 into 5 parts
testing without sub-chunk 1/5
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: dca20dd129d1a9eaf623a5ac227a85348038ef5e8cbd95c02beed2802c9fa1d9
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: a841c49b4abba4f336437dd45f1412bb299a68a918a32a544575b7ffd33a0660
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 9ffdaf8fe42928bd30175cd8c95452b11197b4242963321f1fea84a79517ddea
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [kasan locking atomic_sleep memleak ubsan bug_or_warning], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: 809c111d24225b7b456a84a295606fe0a35fc56100249b75bcd42a69f2b74a6a
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [bug_or_warning kasan locking atomic_sleep memleak ubsan], they are not needed
testing commit 05df91921da664ebba2752a7e45b63e3dddb85de gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: b4cd1610320d4276e386dbd9abdeca42f39475442fa26f987c256a3e96e0eb4d
all runs: crashed: INFO: task hung in do_coredump
representative crash: INFO: task hung in do_coredump, types: [HANG]
the chunk can be dropped
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing current HEAD 7f98ab9da046865d57c102fd3ca9669a29845f67
testing commit 7f98ab9da046865d57c102fd3ca9669a29845f67 gcc
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
kernel signature: b76bd84540d81b5ca899b5f67bc7e79de8e8f7ff0529ab026d08f4109f62b8d9
all runs: crashed: INFO: task hung in vfs_coredump
representative crash: INFO: task hung in vfs_coredump, types: [HANG]
crash still not fixed/happens on the oldest tested release
revisions tested: 8, total time: 2h6m37.176901794s (build: 1h8m36.130409476s, test: 46m14.327292547s)
crash still not fixed or there were kernel test errors
commit msg: Merge tag 'for-6.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
crash: INFO: task hung in vfs_coredump
INFO: task syz.3.16:2841 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.16 state:D stack:12456 pid:2841 tgid:2839 ppid:2390 task_flags:0x400740 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x568/0xfa0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x25/0x110 kernel/sched/core.c:6960
schedule_timeout+0x109/0x120 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x99/0x1b0 kernel/sched/completion.c:121
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:269
coredump_wait fs/coredump.c:534 [inline]
vfs_coredump+0x272/0x2240 fs/coredump.c:1196
get_signal+0x849/0xa00 kernel/signal.c:3019
arch_do_signal_or_restart+0x38/0x220 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x72/0x490 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x31a/0x370 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2d911ae929
RSP: 002b:00007f2d90a7d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 00000000000000ca RBX: 00007f2d913d6088 RCX: 00007f2d911ae929
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f2d913d608c
RBP: 00007f2d913d6080 R08: 00007f2d91f10000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2d913d608c
R13: 0000000000000000 R14: 00007ffd1a8441a0 R15: 00007ffd1a844288
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff82982140 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff82982140 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff82982140 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x36/0x120 kernel/locking/lockdep.c:6775
7 locks held by kworker/u8:3/46:
2 locks held by getty/853:
#0: ffff888105aa10a0 (&tty->ldisc_sem){....}-{0:0}, at: tty_ldisc_ref_wait+0x23/0x60 drivers/tty/tty_ldisc.c:243
#1: ffffc90001c0f2f0 (&ldata->atomic_read_lock){....}-{3:3}, at: n_tty_read+0x17a/0x670 drivers/tty/n_tty.c:2211
2 locks held by syz.1.24/6477:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(none)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x5a/0x90 lib/dump_stack.c:120
nmi_cpu_backtrace+0xd4/0x110 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0xd5/0x140 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x92/0xb0 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0x514/0x620 kernel/hung_task.c:515
kthread+0x107/0x200 kernel/kthread.c:463
ret_from_fork+0x214/0x230 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5567 Comm: syz.9.22 Not tainted syzkaller #0 PREEMPT(none)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x39/0xc0 kernel/locking/spinlock_debug.c:116
Code: de 75 45 48 8b 43 10 65 48 3b 05 da 6a f5 01 74 51 8b 53 08 65 8b 05 ea 6a f5 01 39 c2 74 60 31 c0 ba 01 00 00 00 f0 0f b1 13 <75> 64 65 8b 05 d2 6a f5 01 89 43 08 65 48 8b 05 ab 6a f5 01 48 89
RSP: 0018:ffffc90002907d30 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888101bc6320 RCX: 00000000edb0a1ab
RDX: 0000000000000001 RSI: ffffffff825245ff RDI: ffff888101bc6320
RBP: 0000000000000202 R08: 0000000000080000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888101bc6320
R13: ffff888101bc6040 R14: 0000000000000000 R15: ffffc90002907dd0
FS: 00007f173d4cf6c0(0000) GS:ffff8882b49aa000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0063fe000 CR3: 000000010a73a000 CR4: 00000000003506f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
prepare_to_wait_exclusive+0x29/0xc0 kernel/sched/wait.c:269
io_cqring_wait+0x38b/0x6c0 io_uring/io_uring.c:2704
__do_sys_io_uring_enter+0x4e2/0x7a0 io_uring/io_uring.c:3324
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x6e/0x370 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f173da5e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f173d4cf038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f173dc85fa0 RCX: 00007f173da5e929
RDX: 000000000000235c RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f173dae0b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f173dc85fa0 R15: 00007ffd8f87eea8