* [PATCH v2] iomap: follow the alignment requirement for iomap_dio_hole_iter()
@ 2026-07-31 9:11 Qu Wenruo
2026-08-02 19:14 ` [syzbot ci] " syzbot ci
0 siblings, 1 reply; 4+ messages in thread
From: Qu Wenruo @ 2026-07-31 9:11 UTC (permalink / raw)
To: linux-btrfs, linux-fsdevel, linux-xfs
[BUG]
On the latest development branch, btrfs with 8K block size on 4K page
sized systems will fail all test cases that run fsstress.
One very short example would be:
# $fsstress -n 4 -d $mnt -s 1785675805 -v
0/0: dwrite - no filename
0/1: creat f0 x:0 0 0
0/1: creat add id=0,parent=-1
0/2: write dontcache f0[259 1 0 0 0 0] [816411,3620] 0
0/3: dread - xfsctl(XFS_IOC_DIOINFO) f0[259 1 0 0 32 820031] return 25, fallback to stat()
0/3: dread f0[259 1 0 0 32 820031] [483328,81920] 0
Which triggered the following ASSERT():
assertion failed: IS_ALIGNED(state->start, blocksize) && IS_ALIGNED(state->end + 1, blocksize), in fs/btrfs/extent-io-tree.c:346 (unaligned extent state, blocksize=8192 start=487424 end=565247 state=0x0)
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent-io-tree.c:346!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 4 UID: 0 PID: 648 Comm: fsstress Tainted: G E 7.2.0-rc5-custom+ #431 PREEMPT(full) 7c507bd40d65e4d871e698b22d80f1306bbec543
Tainted: [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
RIP: 0010:validate_extent_state.part.0.isra.0.cold+0x24/0x26 [btrfs]
Call Trace:
<TASK>
insert_state+0x34/0x1a0 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
set_extent_bit+0x440/0x8d0 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
btrfs_lock_extent_bits+0x58/0x380 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
btrfs_dio_iomap_begin+0x319/0xb70 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
iomap_iter+0x1a2/0x370
__iomap_dio_rw+0x236/0x8d0
iomap_dio_rw+0x12/0x30
btrfs_direct_read+0x15f/0x290 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
btrfs_file_read_iter+0x42/0x90 [btrfs 6924944583e4bc91a7c5183a1e7908e745a9b0c8]
vfs_read+0x25e/0x380
ksys_read+0x73/0xe0
do_syscall_64+0xe1/0x790
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7fc3f129318e
</TASK>
[CAUSE]
iomap_dio_hole_iter() is responsible for zeroing out the buffer for a
hole, which calls iov_iter_zero() to zero the range.
However btrfs disables page fault during its __iomap_dio_rw() call, so
iov_iter_zero() can fail at any page boundary.
When the fs block size is larger than page size, iov_iter_zero() may
only have zeroed one page, which is not aligned to the fs block size.
Such one page long range is passed back to btrfs, which triggers the
above ASSERT().
[FIX]
For iomap_dio_hole_iter() round down the copied length, and revert
any excessive range that is beyond the aligned copied length.
Also use @aligned_copied for the size increment and iter advancement.
This should only affect btrfs, which is the only fs utilizing iomap dio
with page fault disabled.
Fixes: 001397f5ef49 ("iomap: add IOMAP_DIO_FSBLOCK_ALIGNED flag")
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Changelog:
v2:
- Rebased to the latest vfs tree
- Slightly rewords the reproducer
In fact no special reproducer needed, any test case running fsstress
can easily trigger it.
The example provided is just the shortest sequence I used to debug the
crash.
---
fs/iomap/direct-io.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 64c6b7286c20..f170976d9de0 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -594,12 +594,20 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
static int iomap_dio_hole_iter(struct iomap_iter *iter, struct iomap_dio *dio)
{
- loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter);
+ loff_t copied = iov_iter_zero(iomap_length(iter), dio->submit.iter);
+ unsigned int bs = iomap_dio_alignment(iter->inode, iter->iomap.bdev,
+ dio->flags);
+ loff_t aligned_copied = round_down(copied, bs);
- dio->size += length;
- if (!length)
+ /*
+ * If fs block size is larger than page size, page fault failure
+ * can cause @copied to be page aligned but not fs block aligned.
+ */
+ iov_iter_revert(dio->submit.iter, copied - aligned_copied);
+ dio->size += aligned_copied;
+ if (!aligned_copied)
return -EFAULT;
- return iomap_iter_advance(iter, length);
+ return iomap_iter_advance(iter, aligned_copied);
}
static int iomap_dio_inline_iter(struct iomap_iter *iomi, struct iomap_dio *dio)
--
2.54.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [syzbot ci] Re: iomap: follow the alignment requirement for iomap_dio_hole_iter()
2026-07-30 1:22 [PATCH] " Qu Wenruo
@ 2026-07-31 11:41 ` syzbot ci
2026-07-31 21:29 ` Qu Wenruo
0 siblings, 1 reply; 4+ messages in thread
From: syzbot ci @ 2026-07-31 11:41 UTC (permalink / raw)
To: linux-btrfs, linux-fsdevel, linux-xfs, wqu; +Cc: syzbot, syzkaller-bugs
syzbot ci has tested the following series
[v1] iomap: follow the alignment requirement for iomap_dio_hole_iter()
https://lore.kernel.org/all/e69cc8a4a9c3f641b97872b50f04c397880077cd.1785374485.git.wqu@suse.com
* [PATCH] iomap: follow the alignment requirement for iomap_dio_hole_iter()
and found the following issue:
general protection fault in __iomap_dio_rw
Full report is available here:
https://ci.syzbot.org/series/81e0fbae-4715-4d62-8e9e-bcd19e46b164
***
general protection fault in __iomap_dio_rw
tree: vfs
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/vfs/vfs.git
base: 70c2cbf8600c7d3a622b77e31136b83d6ac7d86c
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/8d5fee65-291c-46a2-9f9a-d512f8fad82b/config
syz repro: https://ci.syzbot.org/findings/c9f79a18-3316-44ec-b805-b805b1c49325/syz_repro
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: 0 UID: 0 PID: 5842 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:1058 [inline]
RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
FS: 00007fd77743d6c0(0000) GS:ffff88818d951000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000078000 CR3: 000000011606a000 CR4: 00000000000006f0
Call Trace:
<TASK>
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: 0033:0x7fd77659df99
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:00007fd77743d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fd776825fa0 RCX: 00007fd77659df99
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007fd776634ec4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd776826038 R14: 00007fd776825fa0 R15: 00007fff168f4a18
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bdev_get_queue include/linux/blkdev.h:1058 [inline]
RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
FS: 00007fd77743d6c0(0000) GS:ffff8882a8f51000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faa8f64dc80 CR3: 000000011606a000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
0: e2 5a loop 0x5c
2: ff 83 e3 08 75 5c incl 0x5c7508e3(%rbx)
8: e8 ab de 5a ff call 0xff5adeb8
d: 48 8b 9c 24 68 01 00 mov 0x168(%rsp),%rbx
14: 00
15: 48 83 c3 18 add $0x18,%rbx
19: 48 89 d8 mov %rbx,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 48 89 df mov %rbx,%rdi
33: e8 d0 75 c8 ff call 0xffc87608
38: 48 8b 1b mov (%rbx),%rbx
3b: b8 58 01 00 00 mov $0x158,%eax
***
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: syzbot@syzkaller.appspotmail.com
---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.
To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).
The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot ci] Re: iomap: follow the alignment requirement for iomap_dio_hole_iter()
2026-07-31 11:41 ` [syzbot ci] " syzbot ci
@ 2026-07-31 21:29 ` Qu Wenruo
0 siblings, 0 replies; 4+ messages in thread
From: Qu Wenruo @ 2026-07-31 21:29 UTC (permalink / raw)
To: syzbot ci, linux-btrfs, linux-fsdevel, linux-xfs, wqu
Cc: syzbot, syzkaller-bugs
在 2026/7/31 21:11, syzbot ci 写道:
> syzbot ci has tested the following series
>
> [v1] iomap: follow the alignment requirement for iomap_dio_hole_iter()
> https://lore.kernel.org/all/e69cc8a4a9c3f641b97872b50f04c397880077cd.1785374485.git.wqu@suse.com
> * [PATCH] iomap: follow the alignment requirement for iomap_dio_hole_iter()
>
> and found the following issue:
> general protection fault in __iomap_dio_rw
>
> Full report is available here:
> https://ci.syzbot.org/series/81e0fbae-4715-4d62-8e9e-bcd19e46b164
>
> ***
>
> general protection fault in __iomap_dio_rw
>
> tree: vfs
> URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/vfs/vfs.git
> base: 70c2cbf8600c7d3a622b77e31136b83d6ac7d86c
> 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/8d5fee65-291c-46a2-9f9a-d512f8fad82b/config
> syz repro: https://ci.syzbot.org/findings/c9f79a18-3316-44ec-b805-b805b1c49325/syz_repro
>
> 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: 0 UID: 0 PID: 5842 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:1058 [inline]
> RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
> RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
> RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
> RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
> RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
> Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
> RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
> RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
> R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
> R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
> FS: 00007fd77743d6c0(0000) GS:ffff88818d951000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000078000 CR3: 000000011606a000 CR4: 00000000000006f0
> Call Trace:
> <TASK>
> f2fs_dio_read_iter fs/f2fs/file.c:4887 [inline]
This looks like f2fs is not populating iomap->bdev for holes, which is
not unreasonable for a hole.
So I need to update iomap_dio_alignment() for @bdev == NULL cases.
Thanks for the report,
Qu
> 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: 0033:0x7fd77659df99
> 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:00007fd77743d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
> RAX: ffffffffffffffda RBX: 00007fd776825fa0 RCX: 00007fd77659df99
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
> RBP: 00007fd776634ec4 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fd776826038 R14: 00007fd776825fa0 R15: 00007fff168f4a18
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:bdev_get_queue include/linux/blkdev.h:1058 [inline]
> RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
> RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
> RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
> RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
> RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
> Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
> RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
> RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
> R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
> R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
> FS: 00007fd77743d6c0(0000) GS:ffff8882a8f51000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007faa8f64dc80 CR3: 000000011606a000 CR4: 00000000000006f0
> ----------------
> Code disassembly (best guess):
> 0: e2 5a loop 0x5c
> 2: ff 83 e3 08 75 5c incl 0x5c7508e3(%rbx)
> 8: e8 ab de 5a ff call 0xff5adeb8
> d: 48 8b 9c 24 68 01 00 mov 0x168(%rsp),%rbx
> 14: 00
> 15: 48 83 c3 18 add $0x18,%rbx
> 19: 48 89 d8 mov %rbx,%rax
> 1c: 48 c1 e8 03 shr $0x3,%rax
> 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
> 27: fc ff df
> * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
> 2e: 74 08 je 0x38
> 30: 48 89 df mov %rbx,%rdi
> 33: e8 d0 75 c8 ff call 0xffc87608
> 38: 48 8b 1b mov (%rbx),%rbx
> 3b: b8 58 01 00 00 mov $0x158,%eax
>
>
> ***
>
> 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: syzbot@syzkaller.appspotmail.com
>
> ---
> This report is generated by a bot. It may contain errors.
> syzbot ci engineers can be reached at syzkaller@googlegroups.com.
>
> To test a patch for this bug, please reply with `#syz test`
> (should be on a separate line).
>
> The patch should be attached to the email.
> Note: arguments like custom git repos and branches are not supported.
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [syzbot ci] Re: iomap: follow the alignment requirement for iomap_dio_hole_iter()
2026-07-31 9:11 [PATCH v2] iomap: follow the alignment requirement for iomap_dio_hole_iter() Qu Wenruo
@ 2026-08-02 19:14 ` syzbot ci
0 siblings, 0 replies; 4+ messages in thread
From: syzbot ci @ 2026-08-02 19:14 UTC (permalink / raw)
To: linux-btrfs, linux-fsdevel, linux-xfs, wqu; +Cc: syzbot, syzkaller-bugs
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: syzbot@syzkaller.appspotmail.com
---
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To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).
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2026-07-31 9:11 [PATCH v2] iomap: follow the alignment requirement for iomap_dio_hole_iter() Qu Wenruo
2026-08-02 19:14 ` [syzbot ci] " syzbot ci
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2026-07-30 1:22 [PATCH] " Qu Wenruo
2026-07-31 11:41 ` [syzbot ci] " syzbot ci
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