[syzbot] [raid?] general protection fault in md_handle_request

[syzbot <syzbot+89a9ab2a134d092fffae@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    6474fa070f2b Add linux-next specific files for 20260929
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=14dfe035580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3477d5a04d788556
dashboard link: https://syzkaller.appspot.com/bug?extid=89a9ab2a134d092fffae
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10d876c9580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+89a9ab2a134d092fffae@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 UID: 0 PID: 6372 Comm: syz-executor143 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:md_handle_request+0xadd/0xe60 drivers/md/md.c:417
Code: 24 90 00 00 00 48 8b 84 24 a8 00 00 00 42 80 3c 20 00 74 08 48 89 df e8 f1 b2 93 f9 48 8b 1b 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 d4 b2 93 f9 4c 8b 1b 48 8b bc 24
RSP: 0018:ffffc9000415f5c0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff88802b29ddc0
RDX: 0000000000000000 RSI: ffffffff8e9dafe5 RDI: ffff88802b29ddc0
RBP: ffffc9000415f778 R08: ffffffff88a749bc R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff9200082bf70 R14: ffff88807e3680c8 R15: ffff88807e368238
FS:  000055556ca3c400(0000) GS:ffff888124723000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8a7dc59000 CR3: 000000007831e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __submit_bio+0x27f/0x340 block/blk-core.c:681
 __submit_bio_noacct block/blk-core.c:724 [inline]
 submit_bio_noacct_nocheck+0x4e8/0xa40 block/blk-core.c:792
 bio_await block/bio.c:1506 [inline]
 submit_bio_wait+0x12a/0x250 block/bio.c:1524
 __blkdev_direct_IO_simple block/fops.c:115 [inline]
 blkdev_direct_IO+0x1167/0x18e0 block/fops.c:451
 blkdev_read_iter+0x223/0x420 block/fops.c:849
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x595/0xa80 fs/read_write.c:574
 ksys_pread64 fs/read_write.c:764 [inline]
 __do_sys_pread64 fs/read_write.c:772 [inline]
 __se_sys_pread64 fs/read_write.c:769 [inline]
 __x64_sys_pread64+0x196/0x220 fs/read_write.c:769
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8a7dca9077
Code: 48 89 fa 4c 89 df e8 98 1e 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc5a7b78d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 000055556ca3c400 RCX: 00007f8a7dca9077
RDX: 0000000000001000 RSI: 000055556ca3e000 RDI: 0000000000000009
RBP: 0000000000000096 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffc5a7b79e0
R13: 00007ffc5a7b79d4 R14: 00007ffc5a7b7954 R15: 00007f8a7dc59000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:md_handle_request+0xadd/0xe60 drivers/md/md.c:417
Code: 24 90 00 00 00 48 8b 84 24 a8 00 00 00 42 80 3c 20 00 74 08 48 89 df e8 f1 b2 93 f9 48 8b 1b 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 d4 b2 93 f9 4c 8b 1b 48 8b bc 24
RSP: 0018:ffffc9000415f5c0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff88802b29ddc0
RDX: 0000000000000000 RSI: ffffffff8e9dafe5 RDI: ffff88802b29ddc0
RBP: ffffc9000415f778 R08: ffffffff88a749bc R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff9200082bf70 R14: ffff88807e3680c8 R15: ffff88807e368238
FS:  000055556ca3c400(0000) GS:ffff888124623000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8a7dd14100 CR3: 000000007831e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	24 90                	and    $0x90,%al
   2:	00 00                	add    %al,(%rax)
   4:	00 48 8b             	add    %cl,-0x75(%rax)
   7:	84 24 a8             	test   %ah,(%rax,%rbp,4)
   a:	00 00                	add    %al,(%rax)
   c:	00 42 80             	add    %al,-0x80(%rdx)
   f:	3c 20                	cmp    $0x20,%al
  11:	00 74 08 48          	add    %dh,0x48(%rax,%rcx,1)
  15:	89 df                	mov    %ebx,%edi
  17:	e8 f1 b2 93 f9       	call   0xf993b30d
  1c:	48 8b 1b             	mov    (%rbx),%rbx
  1f:	48 83 c3 18          	add    $0x18,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 d4 b2 93 f9       	call   0xf993b30d
  39:	4c 8b 1b             	mov    (%rbx),%r11
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	bc                   	.byte 0xbc
  3f:	24                   	.byte 0x24


---
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