INFO: task can't die in show_swap_cache_info

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f81e94e91878 Add linux-next specific files for 20211125
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15ae2e9ab00000
kernel config: https://syzkaller.appspot.com/x/.config?x=be9183de0824e4d7
dashboard link: https://syzkaller.appspot.com/bug?extid=bec252dc168110c0f77b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bec252...@syzkaller.appspotmail.com

INFO: task syz-executor.5:20674 can't die for more than 143 seconds.
task:syz-executor.5 state:R running task stack:27032 pid:20674 ppid: 18019 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4983 [inline]
__schedule+0xab2/0x4d90 kernel/sched/core.c:6293
preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
vprintk_emit+0x1c9/0x4f0 kernel/printk/printk.c:2249
vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
_printk+0xba/0xed kernel/printk/printk.c:2269
show_swap_cache_info+0x7c/0x130 mm/swap_state.c:76
show_free_areas+0xc9e/0x1120 mm/page_alloc.c:6079
show_mem+0x31/0x191 lib/show_mem.c:17
warn_alloc_show_mem mm/page_alloc.c:4213 [inline]
warn_alloc.cold+0x10e/0x17a mm/page_alloc.c:4236
__vmalloc_area_node mm/vmalloc.c:2964 [inline]
__vmalloc_node_range+0x883/0xab0 mm/vmalloc.c:3065
alloc_thread_stack_node kernel/fork.c:244 [inline]
dup_task_struct kernel/fork.c:888 [inline]
copy_process+0x926/0x75a0 kernel/fork.c:2025
kernel_clone+0xe7/0xab0 kernel/fork.c:2584
__do_sys_clone+0xc8/0x110 kernel/fork.c:2701
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fca268acf11
RSP: 002b:00007fffe114d108 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fca23ddf700 RCX: 00007fca268acf11
RDX: 00007fca23ddf9d0 RSI: 00007fca23ddf2f0 RDI: 00000000003d0f00
RBP: 00007fffe114d340 R08: 00007fca23ddf700 R09: 00007fca23ddf700
R10: 00007fca23ddf9d0 R11: 0000000000000206 R12: 00007fffe114d1be
R13: 00007fffe114d1bf R14: 00007fca23ddf300 R15: 0000000000022000
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8bb83220 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
1 lock held by in:imklog/6450:
#0: ffff88806fe26870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
2 locks held by agetty/6469:
#0: ffff888011b55098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
#1: ffffc90002b4c2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
4 locks held by kworker/0:4/7926:
#0: ffff8880b9c39d58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:489
#1: ffff8880b9c279c8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x3e7/0x4e0 kernel/sched/psi.c:891
#2: ffff8880b9c282f0 (krc.lock){..-.}-{2:2}, at: kfree_rcu_monitor+0x2f/0x830 kernel/rcu/tree.c:3373
#3: ffff8880b9c28518 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:946
1 lock held by syz-executor.2/20437:

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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.