[moderation] [iomap?] general protection fault in iomap_read_end

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c03e9c42ae8f Merge tag 'dma-mapping-6.19-2026-01-20' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=102e279a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e2e5d7c9c1e01cf4
dashboard link: https://syzkaller.appspot.com/bug?extid=fd66964b91e778f8b400
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [bra...@kernel.org djw...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@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/d900f083ada3/non_bootable_disk-c03e9c42.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e12d5703a15f/vmlinux-c03e9c42.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c24e42bb74e4/bzImage-c03e9c42.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fd6696...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 5344 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:kasan_byte_accessible+0x12/0x30 mm/kasan/generic.c:210
Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cc cc cc cc 66 66 66 66 66 66 2e
RSP: 0018:ffffc9000ee5df50 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: ffffffff8b7d16ad RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8b7d16ad RDI: 0000000000000003
RBP: ffffffff825ed37e R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f9df0f R12: 0000000000000000
R13: 000000000000001a R14: 000000000000001a R15: 0000000000000001
FS: 00007fa2bdab36c0(0000) GS:ffff88808cf1d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f074e5c4ad8 CR3: 0000000012634000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__kasan_check_byte+0x12/0x40 mm/kasan/common.c:573
kasan_check_byte include/linux/kasan.h:402 [inline]
lock_acquire+0x84/0x330 kernel/locking/lockdep.c:5842
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
iomap_read_end+0x4e/0x2d0 fs/iomap/buffered-io.c:458
iomap_readahead+0x993/0xc10 fs/iomap/buffered-io.c:643
fuse_readahead+0x202/0x270 fs/fuse/file.c:1084
read_pages+0x193/0x5a0 mm/readahead.c:163
page_cache_ra_unbounded+0x74f/0x980 mm/readahead.c:302
do_page_cache_ra mm/readahead.c:332 [inline]
force_page_cache_ra mm/readahead.c:361 [inline]
page_cache_sync_ra+0x433/0xc40 mm/readahead.c:579
filemap_get_pages+0x4c5/0x1ec0 mm/filemap.c:2690
filemap_read+0x447/0x1230 mm/filemap.c:2800
fuse_cache_read_iter fs/fuse/file.c:1105 [inline]
fuse_file_read_iter+0x4a6/0x580 fs/fuse/file.c:1828
__kernel_read+0x504/0x9b0 fs/read_write.c:530
integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline]
ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
ima_calc_file_hash+0x12c3/0x17f0 security/integrity/ima/ima_crypto.c:568
ima_collect_measurement+0x48b/0x930 security/integrity/ima/ima_api.c:293
process_measurement+0x12e0/0x1cb0 security/integrity/ima/ima_main.c:406
ima_file_check+0xdf/0x130 security/integrity/ima/ima_main.c:663
security_file_post_open+0xb3/0x260 security/security.c:2652
do_open fs/namei.c:4639 [inline]
path_openat+0x34cb/0x3e20 fs/namei.c:4796
do_filp_open+0x22d/0x490 fs/namei.c:4823
do_sys_openat2+0x12f/0x220 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_open fs/open.c:1444 [inline]
__se_sys_open fs/open.c:1440 [inline]
__x64_sys_open+0x11e/0x150 fs/open.c:1440
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa2bcb9acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa2bdab3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fa2bce15fa0 RCX: 00007fa2bcb9acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0
RBP: 00007fa2bcc08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa2bce16038 R14: 00007fa2bce15fa0 R15: 00007fff06e0b1d8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kasan_byte_accessible+0x12/0x30 mm/kasan/generic.c:210
Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cc cc cc cc 66 66 66 66 66 66 2e
RSP: 0018:ffffc9000ee5df50 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: ffffffff8b7d16ad RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8b7d16ad RDI: 0000000000000003
RBP: ffffffff825ed37e R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f9df0f R12: 0000000000000000
R13: 000000000000001a R14: 000000000000001a R15: 0000000000000001
FS: 00007fa2bdab36c0(0000) GS:ffff88808cf1d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f074e5c4ad8 CR3: 0000000012634000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 4 bytes skipped:
0: 0f 1f 40 00 nopl 0x0(%rax)
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 0f 1f 40 d6 nopl -0x2a(%rax)
18: 48 c1 ef 03 shr $0x3,%rdi
1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
23: fc ff df
* 26: 0f b6 04 07 movzbl (%rdi,%rax,1),%eax <-- trapping instruction
2a: 3c 08 cmp $0x8,%al
2c: 0f 92 c0 setb %al
2f: c3 ret
30: cc int3
31: cc int3
32: cc int3
33: cc int3
34: cc int3
35: 66 data16
36: 66 data16
37: 66 data16
38: 66 data16
39: 66 data16
3a: 66 data16
3b: 2e cs


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