[syzbot] upstream boot error: WARNING in __context_tracking_enter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8b12a62a Merge tag 'drm-fixes-2021-03-19' of git://anongit..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17e815aed00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfeed364fc353c32
dashboard link: https://syzkaller.appspot.com/bug?extid=f09a12b2c77bfbbf51bd
userspace arch: arm

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f09a12b2c77bfbbf51bd@xxxxxxxxxxxxxxxxxxxxxxxxx

l2tp_core: L2TP core driver, V2.0
l2tp_ip: L2TP IP encapsulation support (L2TPv3)
l2tp_netlink: L2TP netlink interface
l2tp_eth: L2TP ethernet pseudowire support (L2TPv3)
l2tp_ip6: L2TP IP encapsulation support for IPv6 (L2TPv3)
8021q: 802.1Q VLAN Support v1.8
sctp: Hash tables configured (bind 64/102)
NET: Registered protocol family 21
Registered RDS/infiniband transport
Registered RDS/tcp transport
NET: Registered protocol family 43
9pnet: Installing 9P2000 support
Key type dns_resolver registered
Key type ceph registered
libceph: loaded (mon/osd proto 15/24)
NET: Registered protocol family 40
Registering SWP/SWPB emulation handler
registered taskstats version 1
Loading compiled-in X.509 certificates
Loaded X.509 cert 'Build time autogenerated kernel key: f850c787ad998c396ae089c083b940ff0a9abb77'
zswap: loaded using pool lzo/zbud
Key type ._fscrypt registered
Key type .fscrypt registered
Key type fscrypt-provisioning registered
Key type big_key registered
Key type encrypted registered
ima: No TPM chip found, activating TPM-bypass!
ima: Allocated hash algorithm: sha256
ima: No architecture policies found
evm: Initialising EVM extended attributes:
evm: security.selinux
evm: security.ima
evm: security.capability
evm: HMAC attrs: 0x1
printk: console [netcon0] enabled
netconsole: network logging started
gtp: GTP module loaded (pdp ctx size 64 bytes)
ALSA device list:
  #0: Dummy 1
  #1: Loopback 1
  #2: Virtual MIDI Card 1
  #3: ARM AC'97 Interface PL041 rev0 at 0x1c040000, irq 36
uart-pl011 1c090000.serial: no DMA platform data
md: Skipping autodetection of RAID arrays. (raid=autodetect will force)
EXT4-fs (vda): mounted filesystem without journal. Opts: (null). Quota mode: none.
VFS: Mounted root (ext4 filesystem) readonly on device 253:0.
devtmpfs: mounted
Freeing unused kernel memory: 2048K
Run /sbin/init as init process
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at include/linux/seqlock.h:271 __seqprop_assert include/linux/seqlock.h:271 [inline]
WARNING: CPU: 0 PID: 1 at include/linux/seqlock.h:271 __seqprop_assert.constprop.0+0xf0/0x11c include/linux/seqlock.h:269
Modules linked in:
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
Backtrace: 
[<81804310>] (dump_backtrace) from [<81804584>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252)
 r7:00000080 r6:60000193 r5:00000000 r4:82b58444
[<8180456c>] (show_stack) from [<8180bc58>] (__dump_stack lib/dump_stack.c:79 [inline])
[<8180456c>] (show_stack) from [<8180bc58>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120)
[<8180bba0>] (dump_stack) from [<81805118>] (panic+0x130/0x378 kernel/panic.c:231)
 r7:81f487d4 r6:82a390e4 r5:00000000 r4:82c6b0d8
[<81804fe8>] (panic) from [<802447b4>] (__warn+0xb0/0x164 kernel/panic.c:605)
 r3:82a2248c r2:00000000 r1:5b71e000 r0:81f487d4
 r7:0000010f
[<80244704>] (__warn) from [<818053c8>] (warn_slowpath_fmt+0x68/0xd4 kernel/panic.c:628)
 r7:8028c4b4 r6:0000010f r5:81f40c30 r4:00000000
[<81805364>] (warn_slowpath_fmt) from [<8028c4b4>] (__seqprop_assert include/linux/seqlock.h:271 [inline])
[<81805364>] (warn_slowpath_fmt) from [<8028c4b4>] (__seqprop_assert.constprop.0+0xf0/0x11c include/linux/seqlock.h:269)
 r8:00000000 r7:82a22498 r6:828ac940 r5:8181fbb0 r4:00000001
[<8028c3c4>] (__seqprop_assert.constprop.0) from [<8028ea54>] (vtime_user_enter+0x1c/0x90 kernel/sched/cputime.c:709)
 r5:8181fbb0 r4:834f0000
[<8028ea38>] (vtime_user_enter) from [<8181fbb0>] (__context_tracking_enter+0x148/0x334 kernel/context_tracking.c:82)
 r7:82a22498 r6:828ac940 r5:ffffe000 r4:00000001
[<8181fa68>] (__context_tracking_enter) from [<80417170>] (context_tracking_enter kernel/context_tracking.c:122 [inline])
[<8181fa68>] (__context_tracking_enter) from [<80417170>] (context_tracking_enter+0x54/0x84 kernel/context_tracking.c:106)
 r7:00000000 r6:00000000 r5:60000193 r4:00000001
[<8041711c>] (context_tracking_enter) from [<804171bc>] (user_enter include/linux/context_tracking.h:28 [inline])
[<8041711c>] (context_tracking_enter) from [<804171bc>] (context_tracking_user_enter+0x1c/0x20 kernel/context_tracking.c:130)
 r5:81820218 r4:00000000
[<804171a0>] (context_tracking_user_enter) from [<802000d4>] (no_work_pending+0x8/0x38)
Exception stack(0x834dffb0 to 0x834dfff8)
ffa0:                                     00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffe0: 00000000 7ec68ef0 00000000 76ee5a00 00000010 00000000
Rebooting in 86400 seconds..


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