Re: [syzbot] INFO: task hung in do_read_cache_folio

syzbot
2022-07-02T20:05:28Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 089866061428 Merge tag 'libnvdimm-fixes-5.19-rc5' of git:/..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13b60400080000
kernel config: https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9
dashboard link: https://syzkaller.appspot.com/bug?extid=be946efe33b2d9664348
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116c61f4080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13805fd4080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+be946efe33b2d9664348@syzkaller.appspotmail.com

INFO: task udevd:3614 blocked for more than 143 seconds.
Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:26160 pid: 3614 ppid: 2974 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5146 [inline]
__schedule+0xa00/0x4b50 kernel/sched/core.c:6458
schedule+0xd2/0x1f0 kernel/sched/core.c:6530
io_schedule+0xba/0x130 kernel/sched/core.c:8645
folio_wait_bit_common+0x4f2/0xa90 mm/filemap.c:1324
folio_wait_bit mm/filemap.c:1473 [inline]
folio_wait_locked include/linux/pagemap.h:1028 [inline]
folio_wait_locked include/linux/pagemap.h:1025 [inline]
do_read_cache_folio+0x4ff/0x760 mm/filemap.c:3530
do_read_cache_page mm/filemap.c:3602 [inline]
read_cache_page+0x59/0x2a0 mm/filemap.c:3611
read_mapping_page include/linux/pagemap.h:759 [inline]
read_part_sector+0xf6/0x920 block/partitions/core.c:715
adfspart_check_ICS+0x9a/0x690 block/partitions/acorn.c:360
check_partition block/partitions/core.c:147 [inline]
blk_add_partitions block/partitions/core.c:600 [inline]
bdev_disk_changed block/partitions/core.c:686 [inline]
bdev_disk_changed+0x629/0xf60 block/partitions/core.c:653
blkdev_get_whole+0x18a/0x2d0 block/bdev.c:686
blkdev_get_by_dev.part.0+0x5ec/0xb90 block/bdev.c:823
blkdev_get_by_dev+0x6b/0x80 block/bdev.c:857
blkdev_open+0x13c/0x2c0 block/fops.c:481
do_dentry_open+0x4a1/0x11f0 fs/open.c:848
do_open fs/namei.c:3520 [inline]
path_openat+0x1c71/0x2910 fs/namei.c:3653
do_filp_open+0x1aa/0x400 fs/namei.c:3680
do_sys_openat2+0x16d/0x4c0 fs/open.c:1278
do_sys_open fs/open.c:1294 [inline]
__do_sys_openat fs/open.c:1310 [inline]
__se_sys_openat fs/open.c:1305 [inline]
__x64_sys_openat+0x13f/0x1f0 fs/open.c:1305
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+0x46/0xb0
RIP: 0033:0x7f2cc1991697
RSP: 002b:00007fff60a9cbc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000056135a372c20 RCX: 00007f2cc1991697
RDX: 00000000000a0800 RSI: 000056135a36ab20 RDI: 00000000ffffff9c
RBP: 000056135a36ab20 R08: 0000000000000001 R09: 00007fff60ba0080
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800
R13: 000056135a368130 R14: 0000000000000001 R15: 000056135a347910
</TASK>
INFO: task syz-executor325:3615 blocked for more than 143 seconds.
Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor325 state:D stack:27272 pid: 3615 ppid: 3613 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5146 [inline]
__schedule+0xa00/0x4b50 kernel/sched/core.c:6458
schedule+0xd2/0x1f0 kernel/sched/core.c:6530
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6589
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0xa70/0x1350 kernel/locking/mutex.c:747
blkdev_put+0xbc/0x770 block/bdev.c:912
blkdev_close+0x64/0x80 block/fops.c:495
__fput+0x277/0x9d0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xaff/0x2a00 kernel/exit.c:795
do_group_exit+0xd2/0x2f0 kernel/exit.c:925
get_signal+0x2542/0x2600 kernel/signal.c:2857
arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869
exit_to_user_mode_loop kernel/entry/common.c:166 [inline]
exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f38c3b625e9
RSP: 002b:00007ffe69332538 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 00007f38c3b625e9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000ffff R11: 0000000000000246 R12: 00007ffe693325b0
R13: 00007ffe693325a0 R14: 00007ffe69332590 R15: 000000000000000c
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8bd86660 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
2 locks held by getty/3288:
#0: ffff888025b35098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
#1: ffffc90002d162e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xe50/0x13c0 drivers/tty/n_tty.c:2124
1 lock held by udevd/3614:
#0: ffff8881472ee118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb90 block/bdev.c:814
1 lock held by syz-executor325/3615:
#0: ffff8881472ee118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xbc/0x770 block/bdev.c:912

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xc1d/0xf50 kernel/hung_task.c:369
kthread+0x2e9/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11 Comm: kworker/u4:1 Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_preemption_disabled+0x3e/0x170 lib/smp_processor_id.c:56
Code: 44 8b 25 c5 b6 8a 76 65 8b 1d 2e 0c 8b 76 81 e3 ff ff ff 7f 31 ff 89 de 0f 1f 44 00 00 85 db 74 11 0f 1f 44 00 00 44 89 e0 5b <5d> 41 5c 41 5d 41 5e c3 0f 1f 44 00 00 9c 5b 81 e3 00 02 00 00 31
RSP: 0018:ffffc90000107850 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000020f16 RCX: ffffffff815e59a8
RDX: 0000000000000001 RSI: 0000000000000003 RDI: 0000000000000000
RBP: ffffffff8a285700 R08: 0000000000000000 R09: ffffffff8dbb9157
R10: fffffbfff1b7722a R11: 0000000000000001 R12: 0000000000000001
R13: ffffffff8a2856c0 R14: ffff8880119c1138 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f2dd4a4680 CR3: 000000000ba8e000 CR4: 0000000000350ee0
Call Trace:
<TASK>
rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1185 [inline]
rcu_lockdep_current_cpu_online+0x2d/0x140 kernel/rcu/tree.c:1177
rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
rcu_read_lock_held_common kernel/rcu/update.c:102 [inline]
rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x480/0x570 kernel/locking/lockdep.c:5636
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:349 [inline]
__get_locked_pte+0x154/0x270 mm/memory.c:1830
get_locked_pte include/linux/mm.h:2132 [inline]
__text_poke+0x1b3/0x8e0 arch/x86/kernel/alternative.c:1052
text_poke arch/x86/kernel/alternative.c:1137 [inline]
text_poke_bp_batch+0x44a/0x6c0 arch/x86/kernel/alternative.c:1483
text_poke_flush arch/x86/kernel/alternative.c:1589 [inline]
text_poke_flush arch/x86/kernel/alternative.c:1586 [inline]
text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1596
arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
jump_label_update+0x32f/0x410 kernel/jump_label.c:830
static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177
static_key_enable+0x16/0x20 kernel/jump_label.c:190
toggle_allocation_gate mm/kfence/core.c:811 [inline]
toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:803
process_one_work+0x996/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e9/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
</TASK>
----------------
Code disassembly (best guess):
0: 44 8b 25 c5 b6 8a 76 mov 0x768ab6c5(%rip),%r12d # 0x768ab6cc
7: 65 8b 1d 2e 0c 8b 76 mov %gs:0x768b0c2e(%rip),%ebx # 0x768b0c3c
e: 81 e3 ff ff ff 7f and $0x7fffffff,%ebx
14: 31 ff xor %edi,%edi
16: 89 de mov %ebx,%esi
18: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
1d: 85 db test %ebx,%ebx
1f: 74 11 je 0x32
21: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
26: 44 89 e0 mov %r12d,%eax
29: 5b pop %rbx
* 2a: 5d pop %rbp <-- trapping instruction
2b: 41 5c pop %r12
2d: 41 5d pop %r13
2f: 41 5e pop %r14
31: c3 retq
32: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
37: 9c pushfq
38: 5b pop %rbx
39: 81 e3 00 02 00 00 and $0x200,%ebx
3f: 31 .byte 0x31