BUG: unable to handle kernel NULL pointer dereference in tomoyo_domain_quota_is_ok

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=158c8446100000
kernel config: https://syzkaller.appspot.com/x/.config?x=d195fe572fb15312
dashboard link: https://syzkaller.appspot.com/bug?extid=05574401c8069014e0d3
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [jmo...@namei.org linux-...@vger.kernel.org linux-secu...@vger.kernel.org penguin...@I-love.SAKURA.ne.jp se...@hallyn.com take...@nttdata.co.jp]

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+055744...@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 2117f6067 P4D 2117f6067 PUD 211ba2067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 32715 Comm: syz-executor.2 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x43/0x60 kernel/kcov.c:202
Code: 24 74 0f 80 e6 01 74 35 8b 90 04 14 00 00 85 d2 74 2b 8b 90 e0 13 00 00 83 fa 02 75 20 48 8b 88 e8 13 00 00 8b 80 e4 13 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 0f
RSP: 0018:ffffc90007bafa08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff83637123 RDI: 0000000000000001
RBP: ffff8880a7aa6e00 R08: ffff888052c88040 R09: fffffbfff190e22d
R10: ffffffff8c871167 R11: fffffbfff190e22c R12: 0000000000000002
R13: 0000000000000056 R14: dffffc0000000000 R15: 0000000000000000
FS: 00007f2183455700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000211799000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tomoyo_domain_quota_is_ok+0x3d3/0x500 security/tomoyo/util.c:1050
tomoyo_supervisor+0x2d5/0xf00 security/tomoyo/common.c:2089
tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
tomoyo_path_number_perm+0x3e9/0x4d0 security/tomoyo/file.c:734
security_file_ioctl+0x6c/0xb0 security/security.c:1465
ksys_ioctl+0x50/0x180 fs/ioctl.c:765
__do_sys_ioctl fs/ioctl.c:780 [inline]
__se_sys_ioctl fs/ioctl.c:778 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2183454c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e9940 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000000007439 RDI: 0000000000000008
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000042b R14: 00000000004c6f12 R15: 00007f21834556d4
Modules linked in:
CR2: 0000000000000000
---[ end trace 36360ee6f1d869d5 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x43/0x60 kernel/kcov.c:202
Code: 24 74 0f 80 e6 01 74 35 8b 90 04 14 00 00 85 d2 74 2b 8b 90 e0 13 00 00 83 fa 02 75 20 48 8b 88 e8 13 00 00 8b 80 e4 13 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 66 0f
RSP: 0018:ffffc90007bafa08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff83637123 RDI: 0000000000000001
RBP: ffff8880a7aa6e00 R08: ffff888052c88040 R09: fffffbfff190e22d
R10: ffffffff8c871167 R11: fffffbfff190e22c R12: 0000000000000002
R13: 0000000000000056 R14: dffffc0000000000 R15: 0000000000000000
FS: 00007f2183455700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c39404740 CR3: 0000000211799000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[Andrey Konovalov]

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#syz invalid