[syzbot ci] Re: iomap: follow the alignment requirement for iomap_dio_hole_iter()

syzbot ci <[email protected]> Sun, 02 Aug 2026 12:14:09 -0700
Newsgroups org.kernel.vger.linux-xfs,dev.linux.lists.syzbot,org.kernel.vger.linux-btrfs,org.kernel.vger.linux-fsdevel
Message-ID <[email protected]>
syzbot ci has tested the following series

[v2] iomap: follow the alignment requirement for iomap_dio_hole_iter()
https://lore.kernel.org/all/9209e7204fc6b7b60c28f196750084be8a2faba8.1785489008.git.wqu@suse.com
* [PATCH v2] iomap: follow the alignment requirement for iomap_dio_hole_iter()

and found the following issue:
general protection fault in iomap_dio_hole_iter

Full report is available here:
https://ci.syzbot.org/series/9d98023b-4249-4697-ab21-ea7cf83805c8

***

general protection fault in iomap_dio_hole_iter

tree:      vfs
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/vfs/vfs.git
base:      fa20f6cb6063f7f1a6a56693d4a8713f19058d23
arch:      amd64
compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config:    https://ci.syzbot.org/builds/a53b891c-9ac3-484a-a77e-61c04d35157f/config
syz repro: https://ci.syzbot.org/findings/8ed3b1e3-7e4e-4c2c-b0f6-934cfea6e536/syz_repro

syz.0.17: attempt to access beyond end of device
loop0: rw=2049, sector=53248, nr_sectors = 976 limit=40427
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: 6257 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:bdev_get_queue include/linux/blkdev.h:1056 [inline]
RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1401 [inline]
RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:412 [inline]
RIP: 0010:iomap_dio_hole_iter+0x1bf/0x390 fs/iomap/direct-io.c:598
Code: fc ff df 80 3c 08 00 74 08 4c 89 ef e8 aa d7 c7 ff 49 8b 6d 00 48 83 c5 18 48 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 ef e8 83 d7 c7 ff 41 bd 58 01 00 00 4c 03
RSP: 0018:ffffc90003eff500 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003eff680 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000018 R08: ffff88816dc38fff R09: 0000000000000000
R10: ffff88816dc38000 R11: ffffed102db87200 R12: 0000000000001000
R13: ffffc90003eff6c8 R14: ffff88816b839c00 R15: 1ffff1102d707388
FS:  00007ffb1678d6c0(0000) GS:ffff8882a8f4b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563ae8dcd0a8 CR3: 0000000110cf4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 iomap_dio_iter fs/iomap/direct-io.c:-1 [inline]
 __iomap_dio_rw+0xe56/0x1ac0 fs/iomap/direct-io.c:823
 f2fs_dio_read_iter fs/f2fs/file.c:4887 [inline]
 f2fs_file_read_iter+0x60b/0x940 fs/f2fs/file.c:4950
 copy_splice_read+0x5ff/0xaa0 fs/splice.c:362
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x4b6/0xcb0 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x195/0x290 fs/splice.c:1228
 do_sendfile+0x52e/0x7c0 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb1599e019
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:00007ffb1678d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ffb15c25fa0 RCX: 00007ffb1599e019
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007ffb15a3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb15c26038 R14: 00007ffb15c25fa0 R15: 00007ffc15b4ab58
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bdev_get_queue include/linux/blkdev.h:1056 [inline]
RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1401 [inline]
RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:412 [inline]
RIP: 0010:iomap_dio_hole_iter+0x1bf/0x390 fs/iomap/direct-io.c:598
Code: fc ff df 80 3c 08 00 74 08 4c 89 ef e8 aa d7 c7 ff 49 8b 6d 00 48 83 c5 18 48 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 ef e8 83 d7 c7 ff 41 bd 58 01 00 00 4c 03
RSP: 0018:ffffc90003eff500 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003eff680 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000018 R08: ffff88816dc38fff R09: 0000000000000000
R10: ffff88816dc38000 R11: ffffed102db87200 R12: 0000000000001000
R13: ffffc90003eff6c8 R14: ffff88816b839c00 R15: 1ffff1102d707388
FS:  00007ffb1678d6c0(0000) GS:ffff8882a8f4b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558d8b221b40 CR3: 0000000110cf4000 CR4: 00000000000006f0
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	df 80 3c 08 00 74    	filds  0x7400083c(%rax)
   6:	08 4c 89 ef          	or     %cl,-0x11(%rcx,%rcx,4)
   a:	e8 aa d7 c7 ff       	call   0xffc7d7b9
   f:	49 8b 6d 00          	mov    0x0(%r13),%rbp
  13:	48 83 c5 18          	add    $0x18,%rbp
  17:	48 89 e8             	mov    %rbp,%rax
  1a:	48 c1 e8 03          	shr    $0x3,%rax
  1e:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  25:	fc ff df
* 28:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2c:	74 08                	je     0x36
  2e:	48 89 ef             	mov    %rbp,%rdi
  31:	e8 83 d7 c7 ff       	call   0xffc7d7b9
  36:	41 bd 58 01 00 00    	mov    $0x158,%r13d
  3c:	4c                   	rex.WR
  3d:	03                   	.byte 0x3


***

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: [email protected]

---
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