general protection fault in vprintk_emit

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 3ee15ba60e6b Add linux-next specific files for 20180712
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11d4192c400000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe1c3df2c7c0c81
dashboard link: https://syzkaller.appspot.com/bug?extid=0d2e1d3286dcc6af61dc
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [linux-...@vger.kernel.org pml...@suse.com
ros...@goodmis.org sergey.se...@gmail.com]

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0d2e1d...@syzkaller.appspotmail.com

binder: undelivered TRANSACTION_ERROR: 29189
ntfs: (device loop0): parse_options(): Option utf8 is no longer supported,
using option nls=utf8. Please use option nls=utf8 in the future and make
sure utf8 is compiled either as a module or into the kernel.
ntfs: (device loop0): parse_options(): The uid option requires an argument.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 27551 Comm: syz-executor7 Not tainted 4.18.0-rc4-next-20180712+
#5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1679 [inline]
RIP: 0010:vprintk_emit+0x5b2/0x910 kernel/printk/printk.c:1923
Code: 98 fe ff ff e8 bf 58 19 00 f3 90 48 c7 c1 a0 23 a1 8a 48 8b 85 a0 fe
ff ff 49 c1 ed 03 0f b6 11 4c 01 e8 4c 8b ad b0 fe ff ff <c6> 00 01 41 88
56 80 0f b6 00 84 c0 74 06 0f 8e 8a 02 00 00 48 8b
RSP: 0000:ffff88019c8c7300 EFLAGS: 00010212
RAX: 1ffff10039865292 RBX: dffffc0000000000 RCX: ffffffff8aa123a0
RDX: 0000000000000000 RSI: ffff88019c8c7580 RDI: ffff8801cc3292b0
RBP: ffff88019c8c74f0 R08: ffff880192a70200 R09: ffff88019c8c6f68
R10: ffffed0039719780 R11: ffff8801cb8cbc07 R12: ffff88019c8c7580
R13: ffffffff81bae641 R14: ffff8801cc3292d8 R15: ffffffff81631741
FS: 0000000001c97940(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ee7157d90 CR3: 00000001cc3ac000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
shrink_slab_memcg mm/vmscan.c:598 [inline]
shrink_slab+0x861/0xa60 mm/vmscan.c:671
shrink_node+0x429/0x16a0 mm/vmscan.c:2735
shrink_zones mm/vmscan.c:2964 [inline]
do_try_to_free_pages+0x3e7/0x1290 mm/vmscan.c:3026
try_to_free_mem_cgroup_pages+0x49d/0xc90 mm/vmscan.c:3324
reclaim_high.constprop.73+0x137/0x1e0 mm/memcontrol.c:2060
mem_cgroup_handle_over_high+0x8d/0x130 mm/memcontrol.c:2085
tracehook_notify_resume include/linux/tracehook.h:195 [inline]
exit_to_usermode_loop+0x287/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197
retint_user+0x8/0x18
RIP: 0033:0x40d7af
Code: 0f 84 c8 02 00 00 48 83 bd 78 ff ff ff 00 0f 84 f9 04 00 00 48 8b 95
68 ff ff ff 44 89 95 38 ff ff ff 4c 8d ac 10 00 f7 ff ff <49> 89 85 90 06
00 00 49 8d 85 10 03 00 00 49 89 95 98 06 00 00 41
RSP: 002b:00007fffd9de3840 EFLAGS: 00010206
RAX: 00007f5ee7137000 RBX: 0000000000020000 RCX: 0000000000455aca
RDX: 0000000000021000 RSI: 0000000000021000 RDI: 0000000000000000
RBP: 00007fffd9de3920 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffd9de3930
R13: 00007f5ee7157700 R14: 000000000072bf6c R15: 0000000000000001
Modules linked in:
Dumping ftrace buffer:
(ftrace buffer empty)
---[ end trace 70daeab2804303bc ]---
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1679 [inline]
RIP: 0010:vprintk_emit+0x5b2/0x910 kernel/printk/printk.c:1923
Code: 98 fe ff ff e8 bf 58 19 00 f3 90 48 c7 c1 a0 23 a1 8a 48 8b 85 a0 fe
ff ff 49 c1 ed 03 0f b6 11 4c 01 e8 4c 8b ad b0 fe ff ff <c6> 00 01 41 88
56 80 0f b6 00 84 c0 74 06 0f 8e 8a 02 00 00 48 8b
RSP: 0000:ffff88019c8c7300 EFLAGS: 00010212
RAX: 1ffff10039865292 RBX: dffffc0000000000 RCX: ffffffff8aa123a0
RDX: 0000000000000000 RSI: ffff88019c8c7580 RDI: ffff8801cc3292b0
RBP: ffff88019c8c74f0 R08: ffff880192a70200 R09: ffff88019c8c6f68
R10: ffffed0039719780 R11: ffff8801cb8cbc07 R12: ffff88019c8c7580
R13: ffffffff81bae641 R14: ffff8801cc3292d8 R15: ffffffff81631741
FS: 0000000001c97940(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ee7157d90 CR3: 00000001cc3ac000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

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