general protection fault in do_fast_syscall_32 (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 152036d1 Merge tag 'nfsd-5.7-rc-2' of git://git.linux-nfs...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bbf462100000
kernel config: https://syzkaller.appspot.com/x/.config?x=efdde85c3af536b5
dashboard link: https://syzkaller.appspot.com/bug?extid=3c1ed6d86cb1ad1b6dbb
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+3c1ed6...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 14783 Comm: syz-executor.2 Not tainted 5.7.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_fast_syscall_32+0x71f/0xe90 arch/x86/entry/common.c:409
Code: 31 ed 48 89 de e8 21 6e 72 00 48 83 fb 2b 0f 85 b9 fe ff ff e8 82 6c 72 00 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 70 77 77 07 70 77 77 07 70 77 77 07 77 00 70 07 70 77 77 07 00
RSP: 0018:ffffc900055f7f18 EFLAGS: 00010802
RAX: dffffc0000000000 RBX: 000000000000002b RCX: ffffffff8100c6df
RDX: 1ffff92000abeffb RSI: ffffffff8100c6ee RDI: 0000000000000007
RBP: ffffc900055f7f58 R08: ffff888052ce4080 R09: ffffed100a59c811
R10: ffff888052ce4087 R11: ffffed100a59c810 R12: 00000000f7f0aeb9
R13: 0000000000000000 R14: ffffc900055f7fd8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae700000(0063) knlGS:0000000008acd900
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f5d54c38 CR3: 000000005178a000 CR4: 00000000001406e0
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
Modules linked in:
---[ end trace 60a30a570d673760 ]---
RIP: 0010:do_fast_syscall_32+0x71f/0xe90 arch/x86/entry/common.c:409
Code: 31 ed 48 89 de e8 21 6e 72 00 48 83 fb 2b 0f 85 b9 fe ff ff e8 82 6c 72 00 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 70 77 77 07 70 77 77 07 70 77 77 07 77 00 70 07 70 77 77 07 00
RSP: 0018:ffffc900055f7f18 EFLAGS: 00010802
RAX: dffffc0000000000 RBX: 000000000000002b RCX: ffffffff8100c6df
RDX: 1ffff92000abeffb RSI: ffffffff8100c6ee RDI: 0000000000000007
RBP: ffffc900055f7f58 R08: ffff888052ce4080 R09: ffffed100a59c811
R10: ffff888052ce4087 R11: ffffed100a59c810 R12: 00000000f7f0aeb9
R13: 0000000000000000 R14: ffffc900055f7fd8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae700000(0063) knlGS:0000000008acd900
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f5d54c38 CR3: 000000005178a000 CR4: 00000000001406e0
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.