[moderation/CI] Re: fuse: compound commands

[syzbot ci <syzbot+ci71c667420ed312f3@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v1] fuse: compound commands
https://lore.kernel.org/all/20251223-fuse-compounds-upstream-v1-0-7bade663947b@ddn.com
* [PATCH RFC 1/2] fuse: add compound command to combine multiple requests
* [PATCH RFC 2/2] fuse: add an implementation of open+getattr

and found the following issue:
general protection fault in fuse_dir_open

Full report is available here:
https://ci.syzbot.org/series/11a1edb1-479b-4bb9-a173-a5aef4cc9455

***

general protection fault in fuse_dir_open

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9094662f6707d1d4b53d18baba459604e8bb0783
arch:      amd64
compiler:  Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
config:    https://ci.syzbot.org/builds/0d046766-2385-4f04-bae0-5a8d6df01c3a/config
C repro:   https://ci.syzbot.org/findings/027737d8-b067-4bd4-90f6-5b236fb8420b/c_repro
syz repro: https://ci.syzbot.org/findings/027737d8-b067-4bd4-90f6-5b236fb8420b/syz_repro

Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 1 UID: 0 PID: 5985 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:fuse_dir_open+0x14e/0x220 fs/fuse/dir.c:1900
Code: eb a7 4d 8d 7e 58 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 e0 77 f3 fe 4d 8b 3f 49 83 c7 2c 4d 89 fc 49 c1 ec 03 <43> 0f b6 04 2c 84 c0 0f 85 82 00 00 00 41 8b 2f 89 ee 83 e6 14 31
RSP: 0018:ffffc90003907860 EFLAGS: 00010203
RAX: 1ffff11022f0688b RBX: ffff8881b9320000 RCX: 0000000000000000
RDX: ffff88810afbba80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8f822b77 R09: 1ffffffff1f0456e
R10: dffffc0000000000 R11: fffffbfff1f0456f R12: 000000000000000b
R13: dffffc0000000000 R14: ffff888117834400 R15: 000000000000005c
FS:  00007fa1fc9506c0(0000) GS:ffff8882a9e1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa1fb1fdfc8 CR3: 000000016abde000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 do_dentry_open+0x7ce/0x1420 fs/open.c:962
 vfs_open+0x3b/0x340 fs/open.c:1094
 do_open fs/namei.c:4628 [inline]
 path_openat+0x340e/0x3dd0 fs/namei.c:4787
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa1fbb8e010
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 69 95 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 bc 95 02 00 8b 44
RSP: 002b:00007fa1fc94fdf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007fa1fbb8e010
RDX: 0000000000010000 RSI: 00002000000000c0 RDI: 00000000ffffff9c
RBP: 00002000000000c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00002000000000c0
R13: 00007fa1fc94feb0 R14: 0000000000000000 R15: 0000200000002280
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:fuse_dir_open+0x14e/0x220 fs/fuse/dir.c:1900
Code: eb a7 4d 8d 7e 58 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 e0 77 f3 fe 4d 8b 3f 49 83 c7 2c 4d 89 fc 49 c1 ec 03 <43> 0f b6 04 2c 84 c0 0f 85 82 00 00 00 41 8b 2f 89 ee 83 e6 14 31
RSP: 0018:ffffc90003907860 EFLAGS: 00010203
RAX: 1ffff11022f0688b RBX: ffff8881b9320000 RCX: 0000000000000000
RDX: ffff88810afbba80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8f822b77 R09: 1ffffffff1f0456e
R10: dffffc0000000000 R11: fffffbfff1f0456f R12: 000000000000000b
R13: dffffc0000000000 R14: ffff888117834400 R15: 000000000000005c
FS:  00007fa1fc9506c0(0000) GS:ffff8882a9e1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa1fb1fdfc8 CR3: 000000016abde000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
   0:	eb a7                	jmp    0xffffffa9
   2:	4d 8d 7e 58          	lea    0x58(%r14),%r15
   6:	4c 89 f8             	mov    %r15,%rax
   9:	48 c1 e8 03          	shr    $0x3,%rax
   d:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  12:	74 08                	je     0x1c
  14:	4c 89 ff             	mov    %r15,%rdi
  17:	e8 e0 77 f3 fe       	call   0xfef377fc
  1c:	4d 8b 3f             	mov    (%r15),%r15
  1f:	49 83 c7 2c          	add    $0x2c,%r15
  23:	4d 89 fc             	mov    %r15,%r12
  26:	49 c1 ec 03          	shr    $0x3,%r12
* 2a:	43 0f b6 04 2c       	movzbl (%r12,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 82 00 00 00    	jne    0xb9
  37:	41 8b 2f             	mov    (%r15),%ebp
  3a:	89 ee                	mov    %ebp,%esi
  3c:	83 e6 14             	and    $0x14,%esi
  3f:	31                   	.byte 0x31


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
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If the report looks fine to you, reply with:
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