ci2 starts bisection 2025-11-08 19:17:25.099232465 +0000 UTC m=+182334.714696205 bisecting fixing commit since 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 building syzkaller on 86341da6b45d602116fb0c60fac1641c24aedbe9 ensuring issue is reproducible on original commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: deb855810f86cf8040804b9ee80783a253dcb2b2efcbdc71d58037058c840569 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] check whether we can drop unnecessary instrumentation disabling configs for [kasan locking atomic_sleep memleak ubsan bug_or_warning], they are not needed testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: b2691ed5fe3e1c3ec30f170120540b6722daeff9a2e4ea288d82d6ef4d174d79 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, 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=3829 full=7619 leaves diff=2129 split chunks (needed=false): <2129> split chunk #0 of len 2129 into 5 parts testing without sub-chunk 1/5 disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: 34a3cf4fbc98cb9edd9cded615698e330f297f22d68a1e191bd3ba1dea23f24e all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: e1facc0f27cea59d8dd154abb25e2e8bf158d20da4b1ef333739ab8a79175108 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] the chunk can be dropped testing without sub-chunk 3/5 disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: fbcc2e9cc6540f2d456947ab11d5d7d266a550ae57253ca6bcb2495acbfcd383 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, 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 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: fb02bb5e985bf8cefa446a3bdaa0a2794549ac5ee1c2e4f1fc04567253343812 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed testing commit 7b34dc04e4ff0f37ba4ad8414f42abae9f8f68e4 gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: 3c6b430e1849ccc6a8aa6b16b6c20dc238419bac6c7299cc44d8c66b6eb28c26 all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] the chunk can be dropped disabling configs for [bug_or_warning kasan locking atomic_sleep memleak ubsan], they are not needed testing current HEAD f6e38ae624cf7eb96fb444a8ca2d07caa8d9c8fe testing commit f6e38ae624cf7eb96fb444a8ca2d07caa8d9c8fe gcc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 kernel signature: a19d6b55ace272506a3e81e62308909e39b5826d0716d040ab96bfaf8478245b all runs: crashed: INFO: task hung in __fdget_pos representative crash: INFO: task hung in __fdget_pos, types: [HANG] crash still not fixed/happens on the oldest tested release revisions tested: 8, total time: 1h43m24.541503286s (build: 37m45.516941143s, test: 1h2m29.541602249s) crash still not fixed or there were kernel test errors commit msg: Linux 6.1.158 crash: INFO: task hung in __fdget_pos INFO: task syz.3.17:2557 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.17 state:D stack:14768 pid:2557 ppid:2101 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x568/0x840 kernel/sched/core.c:6561 schedule+0x50/0xb0 kernel/sched/core.c:6637 schedule_preempt_disabled+0x2e/0x40 kernel/sched/core.c:6696 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x44c/0x9b0 kernel/locking/mutex.c:747 __fdget_pos+0xa8/0xc0 fs/file.c:1038 fdget_pos include/linux/file.h:74 [inline] __do_sys_getdents64 fs/readdir.c:365 [inline] __se_sys_getdents64+0x4d/0xf0 fs/readdir.c:354 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f31a788eec9 RSP: 002b:00007f31a76de038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f31a7ae6090 RCX: 00007f31a788eec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f31a7911f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f31a7ae6128 R14: 00007f31a7ae6090 R15: 00007ffd74e313c8 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff827717a8 (rcu_tasks.tasks_gp_mutex){....}-{3:3}, at: rcu_tasks_one_gp kernel/rcu/tasks.h:517 [inline] #0: ffffffff827717a8 (rcu_tasks.tasks_gp_mutex){....}-{3:3}, at: rcu_tasks_kthread+0x97/0x4c0 kernel/rcu/tasks.h:562 1 lock held by khungtaskd/27: #0: ffffffff82771568 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff82771568 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff82771568 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x2a/0xf0 kernel/locking/lockdep.c:6513 2 locks held by getty/480: #0: ffff888104e81098 (&tty->ldisc_sem){....}-{0:0}, at: tty_ldisc_ref_wait+0x1c/0x40 drivers/tty/tty_ldisc.c:244 #1: ffffc900003fb2f0 (&ldata->atomic_read_lock){....}-{3:3}, at: n_tty_read+0x19e/0x6d0 drivers/tty/n_tty.c:2198 2 locks held by syz.3.17/2556: #0: ffff88810669bee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b70150 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.3.17/2557: #0: ffff88810669bee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.4.18/3014: #0: ffff888105eb7ae8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b70690 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.4.18/3017: #0: ffff888105eb7ae8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.5.19/3474: #0: ffff888100242ee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b70bd0 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.5.19/3477: #0: ffff888100242ee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.6.20/3934: #0: ffff88810534e8e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b71110 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.6.20/3937: #0: ffff88810534e8e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.7.21/4394: #0: ffff8881077af2e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b71650 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.7.21/4397: #0: ffff8881077af2e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.8.22/4854: #0: ffff888105b8fce8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff88811c8fc150 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.8.22/4857: #0: ffff888105b8fce8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.9.23/5314: #0: ffff888100228ee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff888113b71b90 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.9.23/5317: #0: ffff888100228ee8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.0.24/5774: #0: ffff8881053d5ce8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff88811c8fc690 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.0.24/5777: #0: ffff8881053d5ce8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.1.25/6234: #0: ffff8881002388e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff88811c8fcbd0 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.1.25/6237: #0: ffff8881002388e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 2 locks held by syz.2.26/6694: #0: ffff8881066976e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 #1: ffff88811c8fd110 (&sb->s_type->i_mutex_key#15){....}-{3:3}, at: iterate_dir+0x40/0x180 fs/readdir.c:55 1 lock held by syz.2.26/6697: #0: ffff8881066976e8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0xa8/0xc0 fs/file.c:1038 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x74/0xbb lib/dump_stack.c:106 nmi_cpu_backtrace+0x102/0x160 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0xa5/0x160 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0x533/0x560 kernel/hung_task.c:377 kthread+0xcc/0xe0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741