[Android 6.1] general protection fault in filename_create

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5e1d25ac2ab6 FROMGIT: BACKPORT: Multi-gen LRU: Fix can_swa..
git tree: android14-6.1
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1787a295a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b8b7a65c87c651
dashboard link: https://syzkaller.appspot.com/bug?extid=321e36793059da7b2e86
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e94533a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1091c751a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e4d7fd9254b/disk-5e1d25ac.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/82768706633b/vmlinux-5e1d25ac.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c20a6db7cf53/bzImage-5e1d25ac.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+321e36...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 444 Comm: syz-executor236 Not tainted 6.1.25-syzkaller-00095-g5e1d25ac2ab6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:__d_entry_type include/linux/dcache.h:394 [inline]
RIP: 0010:d_is_miss include/linux/dcache.h:399 [inline]
RIP: 0010:d_is_negative include/linux/dcache.h:445 [inline]
RIP: 0010:d_is_positive include/linux/dcache.h:455 [inline]
RIP: 0010:filename_create+0x2d2/0x520 fs/namei.c:3813
Code: 92 00 00 00 4c 89 7c 24 28 45 84 e4 0f 95 c0 83 7c 24 14 00 0f 94 c3 20 c3 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 1f 02 00 00 45 8b 26 41 bd 00 00 70 00 be
RSP: 0018:ffffc90001057d20 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 1ffff9200020af00 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: ffffc90001057e10 R08: ffffffff81c9fafb R09: fffff5200020af83
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000600 R14: 0000000000000008 R15: ffffc90001057e80
FS: 00007fb7166176c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb716617d58 CR3: 00000001227ea000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
do_mkdirat+0xbd/0x450 fs/namei.c:4051
__do_sys_mkdir fs/namei.c:4081 [inline]
__se_sys_mkdir fs/namei.c:4079 [inline]
__x64_sys_mkdir+0x6e/0x80 fs/namei.c:4079
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb7166a9c07
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb7166170c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb7166a9c07
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 00000000200001c0
RBP: 00007fb7166170f0 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffc6fc80c27 R11: 0000000000000202 R12: 00000000200001c0
R13: 0000000000000001 R14: 0000000000000000 R15: 2f30656c69662f2e
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__d_entry_type include/linux/dcache.h:394 [inline]
RIP: 0010:d_is_miss include/linux/dcache.h:399 [inline]
RIP: 0010:d_is_negative include/linux/dcache.h:445 [inline]
RIP: 0010:d_is_positive include/linux/dcache.h:455 [inline]
RIP: 0010:filename_create+0x2d2/0x520 fs/namei.c:3813
Code: 92 00 00 00 4c 89 7c 24 28 45 84 e4 0f 95 c0 83 7c 24 14 00 0f 94 c3 20 c3 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 1f 02 00 00 45 8b 26 41 bd 00 00 70 00 be
RSP: 0018:ffffc90001057d20 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 1ffff9200020af00 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
RBP: ffffc90001057e10 R08: ffffffff81c9fafb R09: fffff5200020af83
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000600 R14: 0000000000000008 R15: ffffc90001057e80
FS: 00007fb7166176c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb716617d58 CR3: 00000001227ea000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 92 xchg %eax,%edx
1: 00 00 add %al,(%rax)
3: 00 4c 89 7c add %cl,0x7c(%rcx,%rcx,4)
7: 24 28 and $0x28,%al
9: 45 84 e4 test %r12b,%r12b
c: 0f 95 c0 setne %al
f: 83 7c 24 14 00 cmpl $0x0,0x14(%rsp)
14: 0f 94 c3 sete %bl
17: 20 c3 and %al,%bl
19: 4c 89 f0 mov %r14,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 0f b6 04 08 movzbl (%rax,%rcx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 1f 02 00 00 jne 0x255
36: 45 8b 26 mov (%r14),%r12d
39: 41 bd 00 00 70 00 mov $0x700000,%r13d
3f: be .byte 0xbe


---
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[syzbot]

Bug presence analysis results: the bug reproduces only on Android 6.1.

syzbot has run the reproducer on other relevant kernel trees and got
the following results:

android14-6.1 (commit 5e1d25ac2ab6) on 2023/08/05:
general protection fault in filename_create
Report: https://syzkaller.appspot.com/x/report.txt?x=1130fecda80000

lts (commit b1644a0031cf) on 2023/08/05:
Didn't crash.

upstream (commit 024ff300db33) on 2023/08/05:
Didn't crash.

More details can be found at:
https://syzkaller.appspot.com/bug?extid=321e36793059da7b2e86

[syzbot]

syzbot has bisected this issue to:

commit 57f3ff9648991998d008ecf32f2f9e78a08bfb8b
Author: Daniel Rosenberg <dro...@google.com>
Date: Thu Dec 2 21:50:02 2021 +0000

ANDROID: fuse-bpf v1.1

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12b0b171a80000
start commit: 5e1d25ac2ab6 FROMGIT: BACKPORT: Multi-gen LRU: Fix can_swa..
git tree: android14-6.1
final oops: https://syzkaller.appspot.com/x/report.txt?x=11b0b171a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=16b0b171a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=c5b8b7a65c87c651
dashboard link: https://syzkaller.appspot.com/bug?extid=321e36793059da7b2e86

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e94533a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1091c751a80000

Reported-by: syzbot+321e36...@syzkaller.appspotmail.com
Fixes: 57f3ff964899 ("ANDROID: fuse-bpf v1.1")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection