Message-ID: <673adf75.050a0220.87769.0024.GAE@google.com>
Date: Sun, 17 Nov 2024 22:32:21 -0800
From: syzbot <syzbot+3c4321e10eea460eb606@...kaller.appspotmail.com>
To: acme@...nel.org, adrian.hunter@...el.com, 
	alexander.shishkin@...ux.intel.com, irogers@...gle.com, jolsa@...nel.org, 
	kan.liang@...ux.intel.com, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, mark.rutland@....com, mingo@...hat.com, 
	namhyung@...nel.org, peterz@...radead.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [perf?] INFO: task hung in _free_event

Hello,

syzbot found the following issue on:

HEAD commit:    0a9b9d17f3a7 Merge tag 'pm-6.12-rc8' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12b15df7980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d2aeec8c0b2e420c
dashboard link: https://syzkaller.appspot.com/bug?extid=3c4321e10eea460eb606
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11a54b5f980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=163a94c0580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-0a9b9d17.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b80dd0292210/vmlinux-0a9b9d17.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42a07c5c6678/bzImage-0a9b9d17.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c4321e10eea460eb606@...kaller.appspotmail.com

INFO: task syz-executor369:6029 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc7-syzkaller-00070-g0a9b9d17f3a7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor369 state:D stack:24376 pid:6029  tgid:6029  ppid:5328   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x184f/0x4c30 kernel/sched/core.c:6693
 __schedule_loop kernel/sched/core.c:6770 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6785
 perf_pending_task_sync kernel/events/core.c:5319 [inline]
 _free_event+0x178/0xf60 kernel/events/core.c:5326
 put_event kernel/events/core.c:5454 [inline]
 perf_event_release_kernel+0x7c1/0x850 kernel/events/core.c:5579
 perf_release+0x38/0x40 kernel/events/core.c:5589
 __fput+0x23f/0x880 fs/file_table.c:431
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa2f/0x28e0 kernel/exit.c:939
 do_group_exit+0x207/0x2c0 kernel/exit.c:1088
 get_signal+0x16a3/0x1740 kernel/signal.c:2918
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fa88a3cf9
RSP: 002b:00007ffc8b3be618 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 00000000000017af RBX: 0000000000000000 RCX: 00007f7fa88a3cf9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000c000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/25:
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
2 locks held by getty/5110:
 #0: ffff8880007e10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 6.12.0-rc7-syzkaller-00070-g0a9b9d17f3a7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


---
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