INFO: task hung in prealloc_shrinker (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15429d06480000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=61e597a303a1a4d09519
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61e597...@syzkaller.appspotmail.com

ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.0:23319 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D28632 23319 8161 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write+0x4f/0x90 kernel/locking/rwsem.c:72
prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
alloc_super fs/super.c:265 [inline]
sget_userns+0x7b4/0xcd0 fs/super.c:519
mount_ns+0x8d/0x1d0 fs/super.c:1068
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
kern_mount_data+0x55/0xd0 fs/namespace.c:3278
pid_ns_prepare_proc+0x1a/0x90 fs/proc/root.c:214
alloc_pid+0x721/0x8f0 kernel/pid.c:208
copy_process.part.0+0x3bc0/0x8260 kernel/fork.c:1927
copy_process kernel/fork.c:1710 [inline]
_do_fork+0x22f/0xf30 kernel/fork.c:2219
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7ffae5594dfb
Code: Bad RIP value.
RSP: 002b:00007ffee7d64ac0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffee7d65118 RCX: 00007ffae5594dfb
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000555556bc7400
R10: 0000555556bc76d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffee7d64bb0 R14: 00007ffae56b74f8 R15: 0000000000000006
INFO: task syz-executor.3:23320 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3 D28576 23320 8160 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write+0x4f/0x90 kernel/locking/rwsem.c:72
prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
alloc_super fs/super.c:265 [inline]
sget_userns+0x7b4/0xcd0 fs/super.c:519
mount_ns+0x8d/0x1d0 fs/super.c:1068
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
kern_mount_data+0x55/0xd0 fs/namespace.c:3278
pid_ns_prepare_proc+0x1a/0x90 fs/proc/root.c:214
alloc_pid+0x721/0x8f0 kernel/pid.c:208
copy_process.part.0+0x3bc0/0x8260 kernel/fork.c:1927
copy_process kernel/fork.c:1710 [inline]
_do_fork+0x22f/0xf30 kernel/fork.c:2219
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2721c21dfb
Code: Bad RIP value.
RSP: 002b:00007fff19d08e00 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fff19d09458 RCX: 00007f2721c21dfb
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000555556bf7400
R10: 0000555556bf76d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff19d08ef0 R14: 00007f2721d444f8 R15: 0000000000000006
INFO: task syz-executor.2:23326 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28632 23326 8119 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write+0x4f/0x90 kernel/locking/rwsem.c:72
prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
alloc_super fs/super.c:265 [inline]
sget_userns+0x7b4/0xcd0 fs/super.c:519
mount_ns+0x8d/0x1d0 fs/super.c:1068
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
kern_mount_data+0x55/0xd0 fs/namespace.c:3278
pid_ns_prepare_proc+0x1a/0x90 fs/proc/root.c:214
alloc_pid+0x721/0x8f0 kernel/pid.c:208
copy_process.part.0+0x3bc0/0x8260 kernel/fork.c:1927
copy_process kernel/fork.c:1710 [inline]
_do_fork+0x22f/0xf30 kernel/fork.c:2219
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb89a0fcdfb
Code: Bad RIP value.
RSP: 002b:00007fffe41d3ab0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fffe41d4108 RCX: 00007fb89a0fcdfb
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000555555cfa400
R10: 0000555555cfa6d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffe41d3ba0 R14: 00007fb89a21f4f8 R15: 0000000000000006
INFO: task syz-executor.1:23327 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D28632 23327 9170 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write+0x4f/0x90 kernel/locking/rwsem.c:72
prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
alloc_super fs/super.c:265 [inline]
sget_userns+0x7b4/0xcd0 fs/super.c:519
mount_ns+0x8d/0x1d0 fs/super.c:1068
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
kern_mount_data+0x55/0xd0 fs/namespace.c:3278
pid_ns_prepare_proc+0x1a/0x90 fs/proc/root.c:214
alloc_pid+0x721/0x8f0 kernel/pid.c:208
copy_process.part.0+0x3bc0/0x8260 kernel/fork.c:1927
copy_process kernel/fork.c:1710 [inline]
_do_fork+0x22f/0xf30 kernel/fork.c:2219
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f7f866d9dfb
Code: Bad RIP value.
RSP: 002b:00007fff2b31f360 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fff2b31f9b8 RCX: 00007f7f866d9dfb
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 00005555573ee400
R10: 00005555573ee6d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff2b31f450 R14: 00007f7f867fc4f8 R15: 0000000000000006

Showing all locks held in the system:
3 locks held by kworker/u4:1/23:
1 lock held by khungtaskd/1568:
#0: 000000000be48da9 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
3 locks held by khugepaged/1578:
1 lock held by systemd-journal/4687:
2 locks held by in:imklog/7872:
2 locks held by agetty/8052:
#0: 000000003d10904c (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 00000000b3ab419b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
1 lock held by syz-fuzzer/8160:
#0: 00000000f19a5ea6 (&ep->mtx){+.+.}, at: ep_scan_ready_list+0x7f5/0x9a0 fs/eventpoll.c:688
2 locks held by syz-fuzzer/10466:
2 locks held by kworker/u4:5/8857:
4 locks held by kworker/1:4/9479:
#0: 0000000018eace1f ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000000e42e1a0 ((work_completion)(&ns->proc_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 0000000030c2c516 (&type->s_umount_key#28){++++}, at: deactivate_super+0x16c/0x1a0 fs/super.c:359
#3: 00000000d49a117a (shrinker_rwsem){++++}, at: unregister_memcg_shrinker mm/vmscan.c:221 [inline]
#3: 00000000d49a117a (shrinker_rwsem){++++}, at: unregister_shrinker+0x24d/0x300 mm/vmscan.c:436
3 locks held by kworker/0:5/5557:
2 locks held by syz-executor.2/21840:
2 locks held by syz-executor.2/23218:
2 locks held by syz-executor.4/23234:
#0: 0000000066cfd0d0 (&type->s_umount_key#37){++++}, at: deactivate_super+0x16c/0x1a0 fs/super.c:359
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: unregister_memcg_shrinker mm/vmscan.c:221 [inline]
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: unregister_shrinker+0x24d/0x300 mm/vmscan.c:436
2 locks held by syz-executor.0/23319:
#0: 000000000f3ee682 (&type->s_umount_key#4/1){+.+.}, at: alloc_super fs/super.c:226 [inline]
#0: 000000000f3ee682 (&type->s_umount_key#4/1){+.+.}, at: sget_userns+0x20b/0xcd0 fs/super.c:519
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
2 locks held by syz-executor.3/23320:
#0: 00000000a6b846b0 (&type->s_umount_key#4/1){+.+.}, at: alloc_super fs/super.c:226 [inline]
#0: 00000000a6b846b0 (&type->s_umount_key#4/1){+.+.}, at: sget_userns+0x20b/0xcd0 fs/super.c:519
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
2 locks held by syz-executor.2/23326:
#0: 000000008c18a036 (&type->s_umount_key#4/1){+.+.}, at: alloc_super fs/super.c:226 [inline]
#0: 000000008c18a036 (&type->s_umount_key#4/1){+.+.}, at: sget_userns+0x20b/0xcd0 fs/super.c:519
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
2 locks held by syz-executor.1/23327:
#0: 00000000bfc35990 (&type->s_umount_key#4/1){+.+.}, at: alloc_super fs/super.c:226 [inline]
#0: 00000000bfc35990 (&type->s_umount_key#4/1){+.+.}, at: sget_userns+0x20b/0xcd0 fs/super.c:519
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_memcg_shrinker mm/vmscan.c:194 [inline]
#1: 00000000d49a117a (shrinker_rwsem){++++}, at: prealloc_shrinker+0x176/0x340 mm/vmscan.c:382
4 locks held by kworker/1:1/23335:
#0: 0000000018eace1f ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.