[v6.1] WARNING in ext4_iomap_begin (5)

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syzbot

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3:25 AM (19 hours ago) 3:25 AM
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=178c3fde580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=400cf40c7f3ce6fcc95c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a9aa438e39c2/disk-dc5c83b7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a7b5afd2e170/vmlinux-dc5c83b7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c7673d370fb/bzImage-dc5c83b7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+400cf4...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 4870 at fs/ext4/inode.c:3468 ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Modules linked in:
CPU: 1 PID: 4870 Comm: syz.3.103 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Code: 6d 44 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 7d e1 5c ff 4c 8d ac 24 d0 00 00 00 e9 70 ff ff ff e8 6b e1 5c ff <0f> 0b 41 be de ff ff ff e9 62 f7 ff ff 44 89 e9 80 e1 07 38 c1 0f
RSP: 0018:ffffc9000d7df040 EFLAGS: 00010283
RAX: ffffffff82255285 RBX: 1ffff92001afbe1c RCX: 0000000000080000
RDX: ffffc9000e09a000 RSI: 000000000000a8d4 RDI: 000000000000a8d5
RBP: ffffc9000d7df1b8 R08: ffff888070379467 R09: 1ffff1100e06f28c
R10: dffffc0000000000 R11: ffffed100e06f28d R12: 00000000000000d4
R13: ffff88807037978a R14: 000000000000000b R15: 0000000000000000
FS: 00007f8226bcd6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8226bacd58 CR3: 00000000268b3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_iter+0x671/0x1000 fs/iomap/iter.c:91
__iomap_dio_rw+0xd90/0x1e90 fs/iomap/direct-io.c:597
iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:686
ext4_dio_write_iter fs/ext4/file.c:554 [inline]
ext4_file_write_iter+0x137a/0x17d0 fs/ext4/file.c:674
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x638/0xb10 fs/read_write.c:861
iter_file_splice_write+0x6be/0xcf0 fs/splice.c:685
do_splice_from fs/splice.c:763 [inline]
direct_splice_actor+0xe1/0x130 fs/splice.c:950
splice_direct_to_actor+0x4b8/0xbd0 fs/splice.c:896
do_splice_direct+0x1ce/0x2f0 fs/splice.c:1002
do_sendfile+0x51b/0xe20 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8225d9de99
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:00007f8226bcd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f8226025fa0 RCX: 00007f8225d9de99
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f8225e33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8226026038 R14: 00007f8226025fa0 R15: 00007ffd7a067ae8
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

syzbot

unread,
4:10 AM (18 hours ago) 4:10 AM
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10b966b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=400cf40c7f3ce6fcc95c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=109011b9580000
mounted in repro: https://storage.googleapis.com/syzbot-assets/40da343b0d74/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11fea449580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+400cf4...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5501 at fs/ext4/inode.c:3468 ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Modules linked in:
CPU: 1 PID: 5501 Comm: syz.4.259 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Code: 6d 44 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 7d e1 5c ff 4c 8d ac 24 d0 00 00 00 e9 70 ff ff ff e8 6b e1 5c ff <0f> 0b 41 be de ff ff ff e9 62 f7 ff ff 44 89 e9 80 e1 07 38 c1 0f
RSP: 0018:ffffc9000d02f040 EFLAGS: 00010293
RAX: ffffffff82255285 RBX: 1ffff92001a05e1c RCX: ffff88802bb39e00
RDX: 0000000000000000 RSI: 00000000000000d4 RDI: 0000000000000000
RBP: ffffc9000d02f1b8 R08: ffff88806e98e4a7 R09: 1ffff1100dd31c94
R10: dffffc0000000000 R11: ffffed100dd31c95 R12: 00000000000000d4
R13: ffff88806e98e7ca R14: 000000000000000b R15: 0000000000000000
FS: 00007f5708a626c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f95709d2000 CR3: 00000000726af000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_iter+0x671/0x1000 fs/iomap/iter.c:91
__iomap_dio_rw+0xd90/0x1e90 fs/iomap/direct-io.c:597
iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:686
ext4_dio_write_iter fs/ext4/file.c:554 [inline]
ext4_file_write_iter+0x137a/0x17d0 fs/ext4/file.c:674
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x638/0xb10 fs/read_write.c:861
iter_file_splice_write+0x6be/0xcf0 fs/splice.c:685
do_splice_from fs/splice.c:763 [inline]
direct_splice_actor+0xe1/0x130 fs/splice.c:950
splice_direct_to_actor+0x4b8/0xbd0 fs/splice.c:896
do_splice_direct+0x1ce/0x2f0 fs/splice.c:1002
do_sendfile+0x51b/0xe20 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5707b9de99
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:00007f5708a62028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f5707e25fa0 RCX: 00007f5707b9de99
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f5707c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5707e26038 R14: 00007f5707e25fa0 R15: 00007ffc4c44ead8
</TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

syzbot

unread,
6:20 AM (16 hours ago) 6:20 AM
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13feb746580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=400cf40c7f3ce6fcc95c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176546b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1669909e580000
mounted in repro: https://storage.googleapis.com/syzbot-assets/161a1755a04b/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1552388e580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+400cf4...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5870 at fs/ext4/inode.c:3468 ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Modules linked in:
CPU: 1 PID: 5870 Comm: syz.0.333 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:ext4_iomap_begin+0x9b5/0xb00 fs/ext4/inode.c:3468
Code: 6d 44 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 7d e1 5c ff 4c 8d ac 24 d0 00 00 00 e9 70 ff ff ff e8 6b e1 5c ff <0f> 0b 41 be de ff ff ff e9 62 f7 ff ff 44 89 e9 80 e1 07 38 c1 0f
RSP: 0018:ffffc90003c87040 EFLAGS: 00010293
RAX: ffffffff82255285 RBX: 1ffff92000790e1c RCX: ffff88802a703c00
RDX: 0000000000000000 RSI: 00000000000000d4 RDI: 0000000000000000
RBP: ffffc90003c871b8 R08: ffff888069d68a5f R09: 1ffff1100d3ad14b
R10: dffffc0000000000 R11: ffffed100d3ad14c R12: 00000000000000d4
R13: ffff888069d68d82 R14: 000000000000000b R15: 0000000000000000
FS: 00007f661b3876c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0fc944cc6b CR3: 000000005e9fb000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_iter+0x671/0x1000 fs/iomap/iter.c:91
__iomap_dio_rw+0xd90/0x1e90 fs/iomap/direct-io.c:597
iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:686
ext4_dio_write_iter fs/ext4/file.c:554 [inline]
ext4_file_write_iter+0x137a/0x17d0 fs/ext4/file.c:674
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x638/0xb10 fs/read_write.c:861
iter_file_splice_write+0x6be/0xcf0 fs/splice.c:685
do_splice_from fs/splice.c:763 [inline]
direct_splice_actor+0xe1/0x130 fs/splice.c:950
splice_direct_to_actor+0x4b8/0xbd0 fs/splice.c:896
do_splice_direct+0x1ce/0x2f0 fs/splice.c:1002
do_sendfile+0x51b/0xe20 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f661a59de99
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:00007f661b387028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f661a825fa0 RCX: 00007f661a59de99
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f661a633eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f661a826038 R14: 00007f661a825fa0 R15: 00007ffe230e5408
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