general protection fault in acct_collect

[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=14f07780700000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=97a0fd07ff4c6ee9d83e
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+97a0fd...@syzkaller.appspotmail.com

audit: type=1804 audit(1642030020.916:611): pid=24452 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.5" name="/root/syzkaller-testdir693471085/syzkaller.YbsHhx/698/bus" dev="sda1" ino=14152 res=1
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 24436 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:acct_collect+0x14e/0x810 kernel/acct.c:545
Code: cd 06 00 00 48 8b 6d 00 45 31 ed 48 85 ed 74 6a 49 bf 00 00 00 00 00 fc ff df e8 5d 2c 08 00 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 10 06 00 00 48 89 e8 4c 8b 65 08 48 c1 e8 03
RSP: 0018:ffff888042117ac8 EFLAGS: 00010202
RAX: 000eeeee000eeeef RBX: ffff88809f8b21c0 RCX: 0000000000004165
RDX: 0000000000000000 RSI: ffffffff815a5913 RDI: 0077777000777778
RBP: 0077777000777770 R08: ffffffff8cd38068 R09: 0000000000000000
R10: ffff88803dc00f08 R11: 0000000000000000 R12: 0770776fe0077770
R13: 0770776fe0078770 R14: 0000000000000b00 R15: dffffc0000000000
FS: 00007f7ca35b0700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe8adaf6a8 CR3: 000000009c096000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
do_exit+0x5ff/0x2be0 kernel/exit.c:849
do_group_exit+0x125/0x310 kernel/exit.c:967
get_signal+0x3f2/0x1f70 kernel/signal.c:2589
do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799
exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f7ca4c3aeb9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7ca35b0168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: 00000000000007d6 RBX: 00007f7ca4d4df60 RCX: 00007f7ca4c3aeb9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000006
RBP: 00007f7ca4c9508d R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000a808 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe5389076f R14: 00007f7ca35b0300 R15: 0000000000022000
Modules linked in:
---[ end trace e32779d580ed7efd ]---
RIP: 0010:acct_collect+0x14e/0x810 kernel/acct.c:545
Code: cd 06 00 00 48 8b 6d 00 45 31 ed 48 85 ed 74 6a 49 bf 00 00 00 00 00 fc ff df e8 5d 2c 08 00 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 10 06 00 00 48 89 e8 4c 8b 65 08 48 c1 e8 03
RSP: 0018:ffff888042117ac8 EFLAGS: 00010202
RAX: 000eeeee000eeeef RBX: ffff88809f8b21c0 RCX: 0000000000004165
FAT-fs (loop4): bogus number of reserved sectors
FAT-fs (loop4): Can't find a valid FAT filesystem
RDX: 0000000000000000 RSI: ffffffff815a5913 RDI: 0077777000777778
RBP: 0077777000777770 R08: ffffffff8cd38068 R09: 0000000000000000
R10: ffff88803dc00f08 R11: 0000000000000000 R12: 0770776fe0077770
R13: 0770776fe0078770 R14: 0000000000000b00 R15: dffffc0000000000
FS: 00007f7ca35b0700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555631f708 CR3: 000000009c096000 CR4: 00000000003426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
FAT-fs (loop4): bogus number of reserved sectors
FAT-fs (loop4): Can't find a valid FAT filesystem
----------------
Code disassembly (best guess):
0: cd 06 int $0x6
2: 00 00 add %al,(%rax)
4: 48 8b 6d 00 mov 0x0(%rbp),%rbp
8: 45 31 ed xor %r13d,%r13d
b: 48 85 ed test %rbp,%rbp
e: 74 6a je 0x7a
10: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
17: fc ff df
1a: e8 5d 2c 08 00 callq 0x82c7c
1f: 48 8d 7d 08 lea 0x8(%rbp),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction
2f: 0f 85 10 06 00 00 jne 0x645
35: 48 89 e8 mov %rbp,%rax
38: 4c 8b 65 08 mov 0x8(%rbp),%r12
3c: 48 c1 e8 03 shr $0x3,%rax


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[syzbot]

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