syzbot


kernel BUG in ext4_mb_normalize_request

Status: upstream: reported C repro on 2025/12/18 17:49
Reported-by: syzbot+16dfafdbe48358333904@syzkaller.appspotmail.com
First crash: 4d04h, last: 2d10h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_mb_normalize_request ext4 -1 2 153d 230d 0/29 auto-obsoleted due to no activity on 2025/10/30 08:12

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/ext4/mballoc.c:3676!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8724 Comm: syz.0.1472 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ext4_mb_normalize_request+0x1283/0x12e0 fs/ext4/mballoc.c:3676
Code: 4d a8 80 e1 07 80 c1 03 38 c1 0f 8c 79 fc ff ff 48 8b 7d a8 e8 7e c8 cb ff e9 6b fc ff ff e8 f4 d9 91 ff 0f 0b e8 ed d9 91 ff <0f> 0b e8 e6 d9 91 ff 0f 0b e8 df d9 91 ff 0f 0b e8 d8 d9 91 ff 0f
RSP: 0018:ffffc900023d6bf0 EFLAGS: 00010293
RAX: ffffffff81d1ca93 RBX: 0000000000000027 RCX: ffff88811269a780
RDX: 0000000000000000 RSI: 0000000000000027 RDI: 0000000000000030
RBP: ffffc900023d6cd0 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200047ad70 R11: 1ffff9200047ad70 R12: 0000000000000030
R13: 0000000000000027 R14: ffff88811c522a80 R15: 0000000000000000
FS:  00007f11a65246c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa344b74000 CR3: 0000000115f6a000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_mb_new_blocks+0xc21/0x42f0 fs/ext4/mballoc.c:5233
 ext4_ext_map_blocks+0x167f/0x5d80 fs/ext4/extents.c:4335
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2452 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline]
 ext4_writepages+0x11d5/0x2e00 fs/ext4/inode.c:2873
 do_writepages+0x12a/0x270 mm/page-writeback.c:2380
 __filemap_fdatawrite_range+0x2bc/0x360 mm/filemap.c:427
 filemap_write_and_wait_range+0x65/0x290 mm/filemap.c:660
 ext4_punch_hole+0x120/0xad0 fs/ext4/inode.c:4118
 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4758
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 madvise_remove mm/madvise.c:880 [inline]
 madvise_vma_behavior mm/madvise.c:904 [inline]
 madvise_walk_vmas mm/madvise.c:1131 [inline]
 do_madvise+0x12cf/0x1df0 mm/madvise.c:1308
 __do_sys_madvise mm/madvise.c:1322 [inline]
 __se_sys_madvise mm/madvise.c:1320 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1320
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f11a66b4749
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:00007f11a6524038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f11a690afa0 RCX: 00007f11a66b4749
RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007f11a6738f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11a690b038 R14: 00007f11a690afa0 R15: 00007ffc1408bda8
Modules linked in:
---[ end trace 58f061317235e8e5 ]---
RIP: 0010:ext4_mb_normalize_request+0x1283/0x12e0 fs/ext4/mballoc.c:3676
Code: 4d a8 80 e1 07 80 c1 03 38 c1 0f 8c 79 fc ff ff 48 8b 7d a8 e8 7e c8 cb ff e9 6b fc ff ff e8 f4 d9 91 ff 0f 0b e8 ed d9 91 ff <0f> 0b e8 e6 d9 91 ff 0f 0b e8 df d9 91 ff 0f 0b e8 d8 d9 91 ff 0f
RSP: 0018:ffffc900023d6bf0 EFLAGS: 00010293
RAX: ffffffff81d1ca93 RBX: 0000000000000027 RCX: ffff88811269a780
RDX: 0000000000000000 RSI: 0000000000000027 RDI: 0000000000000030
RBP: ffffc900023d6cd0 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200047ad70 R11: 1ffff9200047ad70 R12: 0000000000000030
R13: 0000000000000027 R14: ffff88811c522a80 R15: 0000000000000000
FS:  00007f11a65246c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa344b74000 CR3: 0000000115f6a000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/19 19:01 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/19 09:38 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/19 06:51 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/18 17:40 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/20 07:34 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/20 05:29 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
2025/12/18 13:29 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_mb_normalize_request
* Struck through repros no longer work on HEAD.