Message-ID: <68dea1d7.050a0220.25d7ab.07bc.GAE@google.com>
Date: Thu, 02 Oct 2025 09:01:27 -0700
From: syzbot <syzbot+08df3e4c9b304b37cb04@...kaller.appspotmail.com>
To: almaz.alexandrovich@...agon-software.com, linux-kernel@...r.kernel.org, 
	linux-usb@...r.kernel.org, ntfs3@...ts.linux.dev, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [ntfs3?] [usb?] general protection fault in rtlock_slowlock_locked

Hello,

syzbot found the following issue on:

HEAD commit:    99bade344cfa Merge tag 'rust-fixes-6.17' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f513a2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=98e114f4eb77e551
dashboard link: https://syzkaller.appspot.com/bug?extid=08df3e4c9b304b37cb04
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/309f13a7cc12/disk-99bade34.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0d782186486b/vmlinux-99bade34.xz
kernel image: https://storage.googleapis.com/syzbot-assets/174f592d16e2/bzImage-99bade34.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+08df3e4c9b304b37cb04@...kaller.appspotmail.com

loop7: detected capacity change from 0 to 4096
Oops: general protection fault, probably for non-canonical address 0xffdffc0000000148: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0xff00000000000a40-0xff00000000000a47]
CPU: 0 UID: 0 PID: 11227 Comm: syz.7.607 Tainted: G        W           6.17.0-rc1-syzkaller-00214-g99bade344cfa #0 PREEMPT_{RT,(full)} 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x78/0x290 kernel/locking/spinlock_debug.c:115
Code: aa 9c 81 48 8d 4c 24 20 48 c1 e9 03 48 b8 f1 f1 f1 f1 04 f3 f3 f3 48 89 4c 24 18 4a 89 04 39 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 9f 01 00 00 41 8b 06 3d ad 4e ad de 0f
RSP: 0018:ffffc900049ff4c0 EFLAGS: 00010807
RAX: 1fe0000000000148 RBX: ff00000000000a40 RCX: 1ffff9200093fe9c
RDX: 0000000000000000 RSI: ffffffff8b620b60 RDI: ff00000000000a40
RBP: ffffc900049ff570 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10053788b9 R12: ffff88808316a1b0
R13: ff00000000000000 R14: ff00000000000a44 R15: dffffc0000000000
FS:  00007f7f773fe6c0(0000) GS:ffff8881268c5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f79182020 CR3: 000000005aace000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 task_blocks_on_rt_mutex kernel/locking/rtmutex.c:1265 [inline]
 rtlock_slowlock_locked+0x8ef/0x4010 kernel/locking/rtmutex.c:1851
 rtlock_slowlock kernel/locking/rtmutex.c:1895 [inline]
 rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
 rt_spin_lock+0x152/0x2c0 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:44 [inline]
 iput_final fs/inode.c:1886 [inline]
 iput+0x5c1/0x9d0 fs/inode.c:1923
 ntfs_fill_super+0x38fa/0x40b0 fs/ntfs3/super.c:1514
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3805
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4321
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f791a038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f773fde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7f773fdef0 RCX: 00007f7f791a038a
RDX: 0000200000000080 RSI: 0000200000000000 RDI: 00007f7f773fdeb0
RBP: 0000200000000080 R08: 00007f7f773fdef0 R09: 0000000002010c10
R10: 0000000002010c10 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f7f773fdeb0 R14: 000000000001f743 R15: 0000200000000380
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x78/0x290 kernel/locking/spinlock_debug.c:115
Code: aa 9c 81 48 8d 4c 24 20 48 c1 e9 03 48 b8 f1 f1 f1 f1 04 f3 f3 f3 48 89 4c 24 18 4a 89 04 39 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 9f 01 00 00 41 8b 06 3d ad 4e ad de 0f
RSP: 0018:ffffc900049ff4c0 EFLAGS: 00010807
RAX: 1fe0000000000148 RBX: ff00000000000a40 RCX: 1ffff9200093fe9c
RDX: 0000000000000000 RSI: ffffffff8b620b60 RDI: ff00000000000a40
RBP: ffffc900049ff570 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10053788b9 R12: ffff88808316a1b0
R13: ff00000000000000 R14: ff00000000000a44 R15: dffffc0000000000
FS:  00007f7f773fe6c0(0000) GS:ffff8881268c5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f79182020 CR3: 000000005aace000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	aa                   	stos   %al,%es:(%rdi)
   1:	9c                   	pushf
   2:	81 48 8d 4c 24 20 48 	orl    $0x4820244c,-0x73(%rax)
   9:	c1 e9 03             	shr    $0x3,%ecx
   c:	48 b8 f1 f1 f1 f1 04 	movabs $0xf3f3f304f1f1f1f1,%rax
  13:	f3 f3 f3
  16:	48 89 4c 24 18       	mov    %rcx,0x18(%rsp)
  1b:	4a 89 04 39          	mov    %rax,(%rcx,%r15,1)
  1f:	4c 8d 77 04          	lea    0x4(%rdi),%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 9f 01 00 00    	jne    0x1d6
  37:	41 8b 06             	mov    (%r14),%eax
  3a:	3d ad 4e ad de       	cmp    $0xdead4ead,%eax
  3f:	0f                   	.byte 0xf


---
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