[Android 6.1] BUG: unable to handle kernel paging request in fuse_dev_do_write

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 270a77dd074c ANDROID: arm64: Check FGT cap before touching..
git tree: android14-6.1
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13a1326a280000
kernel config: https://syzkaller.appspot.com/x/.config?x=772a621c45fe488b
dashboard link: https://syzkaller.appspot.com/bug?extid=aed068c41e83dab87637
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115f2e5a280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1752afce280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d8ee13b622ed/disk-270a77dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fbabbd618850/vmlinux-270a77dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/38acfb585459/bzImage-270a77dd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aed068...@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffed10497c01ff
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23fff2067 P4D 23fff2067 PUD 23fff0067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 395 Comm: syz-executor437 Not tainted 6.1.25-syzkaller-00241-g270a77dd074c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
RIP: 0010:fuse_dev_do_write+0x3828/0x6110 fs/fuse/dev.c:1938
Code: 49 8b 7d 00 48 89 f0 48 c1 e8 03 0f b6 04 10 84 c0 48 89 fb 0f 85 80 27 00 00 44 8b 2e 41 ff cd 49 01 fd 4c 89 e8 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 94 27 00 00 41 c6 45 00 00 41 80 3c 17 00
RSP: 0018:ffffc90000b27840 EFLAGS: 00010a07
RAX: 1ffff110497c01ff RBX: ffff88814be01000 RCX: ffff8881096c1300
RDX: dffffc0000000000 RSI: ffffc9000074f9e8 RDI: ffff88814be01000
RBP: ffffc90000b27b70 R08: ffffffff820ecff5 R09: fffff9400088a907
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff11021a074e1
R13: ffff88824be00fff R14: ffff88812e08cbf0 R15: 1ffff11025c1197e
FS: 00007fb348485700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed10497c01ff CR3: 000000012c429000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
fuse_dev_write+0x144/0x1d0 fs/fuse/dev.c:1988
call_write_iter include/linux/fs.h:2212 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x8d1/0xe80 fs/read_write.c:584
ksys_write+0x199/0x2c0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:646
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: 0033:0x7fb3484f5909
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb3484852f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb3485824d0 RCX: 00007fb3484f5909
RDX: 0000000000000010 RSI: 00000000200042c0 RDI: 0000000000000003
RBP: 00007fb34854f26c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb34854b260
R13: 00007fb34854d268 R14: 2f30656c69662f2e R15: 00007fb3485824d8
</TASK>
Modules linked in:
CR2: ffffed10497c01ff
---[ end trace 0000000000000000 ]---
RIP: 0010:fuse_dev_do_write+0x3828/0x6110 fs/fuse/dev.c:1938
Code: 49 8b 7d 00 48 89 f0 48 c1 e8 03 0f b6 04 10 84 c0 48 89 fb 0f 85 80 27 00 00 44 8b 2e 41 ff cd 49 01 fd 4c 89 e8 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 94 27 00 00 41 c6 45 00 00 41 80 3c 17 00
RSP: 0018:ffffc90000b27840 EFLAGS: 00010a07
RAX: 1ffff110497c01ff RBX: ffff88814be01000 RCX: ffff8881096c1300
RDX: dffffc0000000000 RSI: ffffc9000074f9e8 RDI: ffff88814be01000
RBP: ffffc90000b27b70 R08: ffffffff820ecff5 R09: fffff9400088a907
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff11021a074e1
R13: ffff88824be00fff R14: ffff88812e08cbf0 R15: 1ffff11025c1197e
FS: 00007fb348485700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed10497c01ff CR3: 000000012c429000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 49 8b 7d 00 mov 0x0(%r13),%rdi
4: 48 89 f0 mov %rsi,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax
f: 84 c0 test %al,%al
11: 48 89 fb mov %rdi,%rbx
14: 0f 85 80 27 00 00 jne 0x279a
1a: 44 8b 2e mov (%rsi),%r13d
1d: 41 ff cd dec %r13d
20: 49 01 fd add %rdi,%r13
23: 4c 89 e8 mov %r13,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 94 27 00 00 jne 0x27ca
36: 41 c6 45 00 00 movb $0x0,0x0(%r13)
3b: 41 80 3c 17 00 cmpb $0x0,(%r15,%rdx,1)


---
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[syzbot]

syzbot has bisected this issue to:

commit c0b8bfdecfa32e394df30c8ad8dab4ac894d1b0b
Author: Daniel Rosenberg <dro...@google.com>
Date: Fri May 20 00:04:23 2022 +0000

ANDROID: fsnotify: Notify lower fs of open

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106f3f2e280000
start commit: 270a77dd074c ANDROID: arm64: Check FGT cap before touching..
git tree: android14-6.1
final oops: https://syzkaller.appspot.com/x/report.txt?x=126f3f2e280000
console output: https://syzkaller.appspot.com/x/log.txt?x=146f3f2e280000

kernel config: https://syzkaller.appspot.com/x/.config?x=772a621c45fe488b
dashboard link: https://syzkaller.appspot.com/bug?extid=aed068c41e83dab87637

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115f2e5a280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1752afce280000

Reported-by: syzbot+aed068...@syzkaller.appspotmail.com
Fixes: c0b8bfdecfa3 ("ANDROID: fsnotify: Notify lower fs of open")

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

[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 bae70267baabf6179fd3f7df0419b16ff1a8e0c3) on 2023/05/18:
BUG: unable to handle kernel paging request in fuse_dev_do_write
Report: https://syzkaller.appspot.com/x/report.txt?x=15d38fa1280000

lts (commit b1644a0031cfb3ca2cbd84c92f771f8ebb62302d) on 2023/05/18:
Didn't crash.

upstream (commit 2d1bcbc6cd703e64caf8df314e3669b4786e008a) on 2023/05/18:
Didn't crash.

More details can be found at:
https://syzkaller.appspot.com/bug?extid=aed068c41e83dab87637