[moderation] [fs?] general protection fault in fsnotify_pre_content

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 805ba04cb7cc Merge tag 'mips_6.14' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148836b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7d796da73b2f708c
dashboard link: https://syzkaller.appspot.com/bug?extid=a0199641a38d4fd9f0ef
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [amir...@gmail.com ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-805ba04c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/85ee30d862e7/vmlinux-805ba04c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0fcbe505a48e/bzImage-805ba04c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a01996...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 1036 Comm: kworker/u4:6 Not tainted 6.13.0-syzkaller-08291-g805ba04cb7cc #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: loop0 loop_rootcg_workfn
RIP: 0010:fsnotify_parent include/linux/fsnotify.h:81 [inline]
RIP: 0010:fsnotify_pre_content+0x16c/0x5b0 fs/notify/fsnotify.c:220
Code: 5c 24 68 48 89 d8 48 c1 e8 03 4d 89 ee 42 80 3c 28 00 74 08 48 89 df e8 d2 4c da ff 4c 8b 3b 4d 8d 6f 28 4c 89 e8 48 c1 e8 03 <42> 80 3c 30 00 74 08 4c 89 ef e8 b5 4c da ff bb 60 06 00 00 49 03
RSP: 0018:ffffc900026af500 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff888044308c28 RCX: ffff888000fea440
RDX: 0000000000000000 RSI: ffffc900026af7c0 RDI: ffffc900026af550
RBP: ffffc900026af5c8 R08: 0000000000000005 R09: ffffffff82366f6d
R10: 0000000000000002 R11: ffff888000fea440 R12: ffff888044308bc0
R13: 0000000000000028 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005578f2d0a0b8 CR3: 0000000011bae000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
fsnotify_file_area_perm include/linux/fsnotify.h:157 [inline]
rw_verify_area+0x21f/0x630 fs/read_write.c:470
vfs_iter_read+0x12d/0x460 fs/read_write.c:905
lo_read_simple drivers/block/loop.c:285 [inline]
do_req_filebacked drivers/block/loop.c:525 [inline]
loop_handle_cmd drivers/block/loop.c:1926 [inline]
loop_process_work+0xd72/0x21c0 drivers/block/loop.c:1961
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
worker_thread+0x870/0xd30 kernel/workqueue.c:3398
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:fsnotify_parent include/linux/fsnotify.h:81 [inline]
RIP: 0010:fsnotify_pre_content+0x16c/0x5b0 fs/notify/fsnotify.c:220
Code: 5c 24 68 48 89 d8 48 c1 e8 03 4d 89 ee 42 80 3c 28 00 74 08 48 89 df e8 d2 4c da ff 4c 8b 3b 4d 8d 6f 28 4c 89 e8 48 c1 e8 03 <42> 80 3c 30 00 74 08 4c 89 ef e8 b5 4c da ff bb 60 06 00 00 49 03
RSP: 0018:ffffc900026af500 EFLAGS: 00010206
RAX: 0000000000000005 RBX: ffff888044308c28 RCX: ffff888000fea440
RDX: 0000000000000000 RSI: ffffc900026af7c0 RDI: ffffc900026af550
RBP: ffffc900026af5c8 R08: 0000000000000005 R09: ffffffff82366f6d
R10: 0000000000000002 R11: ffff888000fea440 R12: ffff888044308bc0
R13: 0000000000000028 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005578f2d0a0b8 CR3: 0000000011bae000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 5c pop %rsp
1: 24 68 and $0x68,%al
3: 48 89 d8 mov %rbx,%rax
6: 48 c1 e8 03 shr $0x3,%rax
a: 4d 89 ee mov %r13,%r14
d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
12: 74 08 je 0x1c
14: 48 89 df mov %rbx,%rdi
17: e8 d2 4c da ff call 0xffda4cee
1c: 4c 8b 3b mov (%rbx),%r15
1f: 4d 8d 6f 28 lea 0x28(%r15),%r13
23: 4c 89 e8 mov %r13,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ef mov %r13,%rdi
34: e8 b5 4c da ff call 0xffda4cee
39: bb 60 06 00 00 mov $0x660,%ebx
3e: 49 rex.WB
3f: 03 .byte 0x3


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[syzbot]

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