general protection fault in do_fast_syscall_32

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 244dc268 Merge tag 'drm-fixes-2020-01-19' of git://anongit..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10fa48d6e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
dashboard link: https://syzkaller.appspot.com/bug?extid=80e16824a137f66724c3
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386
CC: [b...@alien8.de h...@zytor.com linux-...@vger.kernel.org lu...@kernel.org mi...@redhat.com tg...@linutronix.de x...@kernel.org]

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+80e168...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9446 Comm: syz-executor.1 Not tainted 5.5.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_fast_syscall_32+0x779/0xe16 arch/x86/entry/common.c:422
Code: 3a 74 00 4c 39 eb 0f 85 78 fe ff ff e8 b0 39 74 00 00 00 00 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 06 00 00 49 8b 9c 24 90 00 00 00 31 ff 45 31
RSP: 0018:ffffc90002877f10 EFLAGS: 00010047
RAX: dffffc0000000000 RBX: 00000000f7f929a9 RCX: ffffffff8100bb62
RDX: 0000000000000000 RSI: ffffffff8100bb70 RDI: 0000000000000006
RBP: ffffc90002877f48 R08: ffff88808a49c600 R09: ffffed10114938c1
R10: ffffed10114938c0 R11: ffff88808a49c607 R12: ffffc90002877f58
R13: 00000000f7f929a9 R14: 0000000000000000 R15: ffffc90002877fd8
FS: 0000000000000000(0000) GS:ffff8880ae900000(0063) knlGS:0000000008eda900
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000812d0f0 CR3: 00000000785c7000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f929a9
Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:000000000848fd7c EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: 0000000000000000 RBX: 000000000848fda8 RCX: 0000000000000000
RDX: 0000000000000007 RSI: 000000000028532f RDI: 0000000000000000
RBP: 0000000000000007 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 16a6e4d42e489563 ]---
RIP: 0010:do_fast_syscall_32+0x779/0xe16 arch/x86/entry/common.c:422
Code: 3a 74 00 4c 39 eb 0f 85 78 fe ff ff e8 b0 39 74 00 00 00 00 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 24 06 00 00 49 8b 9c 24 90 00 00 00 31 ff 45 31
RSP: 0018:ffffc90002877f10 EFLAGS: 00010047
RAX: dffffc0000000000 RBX: 00000000f7f929a9 RCX: ffffffff8100bb62
RDX: 0000000000000000 RSI: ffffffff8100bb70 RDI: 0000000000000006
RBP: ffffc90002877f48 R08: ffff88808a49c600 R09: ffffed10114938c1
R10: ffffed10114938c0 R11: ffff88808a49c607 R12: ffffc90002877f58
R13: 00000000f7f929a9 R14: 0000000000000000 R15: ffffc90002877fd8
FS: 0000000000000000(0000) GS:ffff8880ae900000(0063) knlGS:0000000008eda900
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000812d0f0 CR3: 00000000785c7000 CR4: 00000000001426e0
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.