[v5.15] general protection fault in xfs_getbmap (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=173697cd980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=ad469178df2e15ac3526
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c71c660545b2/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4f011826cca6/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8ccd1a2c3f8c/bzImage-cc5ec876.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad4691...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 5328 Comm: syz.3.263 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:xfs_getbmap+0x4ef/0x1af0 fs/xfs/xfs_bmap_util.c:494
Code: fe 4c 89 ff 49 83 c7 48 4d 8b 36 e8 2b cf 05 00 89 84 24 8c 00 00 00 4c 89 bc 24 a8 00 00 00 49 83 c7 22 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 85 12 00 00 45 0f b6 3f 4c 89 ff 48 c7
RSP: 0018:ffffc900030e7600 EFLAGS: 00010202
RAX: 0000000000000004 RBX: 1ffff9200061cedc RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc900030e7810 R08: dffffc0000000000 R09: ffffed100bad8011
R10: ffffed100bad8011 R11: 1ffff1100bad8010 R12: dffffc0000000000
R13: 000000000000000b R14: 0000000100000000 R15: 0000000000000022
FS: 00007f35ec0416c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4aaf9e6000 CR3: 000000002ac3a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
xfs_ioc_getbmap+0x1ff/0x660 fs/xfs/xfs_ioctl.c:1555
xfs_file_ioctl+0xa8e/0x1520 fs/xfs/xfs_ioctl.c:2016
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f35eddfb6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f35ec041038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f35ee052090 RCX: 00007f35eddfb6c9
RDX: 0000200000000000 RSI: 00000000c0205838 RDI: 0000000000000004
RBP: 00007f35ede7df91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f35ee052128 R14: 00007f35ee052090 R15: 00007ffe57ee9c78
</TASK>
Modules linked in:
---[ end trace c12e69d076de535b ]---
RIP: 0010:xfs_getbmap+0x4ef/0x1af0 fs/xfs/xfs_bmap_util.c:494
Code: fe 4c 89 ff 49 83 c7 48 4d 8b 36 e8 2b cf 05 00 89 84 24 8c 00 00 00 4c 89 bc 24 a8 00 00 00 49 83 c7 22 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 85 12 00 00 45 0f b6 3f 4c 89 ff 48 c7
RSP: 0018:ffffc900030e7600 EFLAGS: 00010202
RAX: 0000000000000004 RBX: 1ffff9200061cedc RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc900030e7810 R08: dffffc0000000000 R09: ffffed100bad8011
R10: ffffed100bad8011 R11: 1ffff1100bad8010 R12: dffffc0000000000
R13: 000000000000000b R14: 0000000100000000 R15: 0000000000000022
FS: 00007f35ec0416c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200001000000 CR3: 000000002ac3a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: fe 4c 89 ff decb -0x1(%rcx,%rcx,4)
4: 49 83 c7 48 add $0x48,%r15
8: 4d 8b 36 mov (%r14),%r14
b: e8 2b cf 05 00 call 0x5cf3b
10: 89 84 24 8c 00 00 00 mov %eax,0x8c(%rsp)
17: 4c 89 bc 24 a8 00 00 mov %r15,0xa8(%rsp)
1e: 00
1f: 49 83 c7 22 add $0x22,%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 85 12 00 00 jne 0x12bc
37: 45 0f b6 3f movzbl (%r15),%r15d
3b: 4c 89 ff mov %r15,%rdi
3e: 48 rex.W
3f: c7 .byte 0xc7


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