syzbot


kernel BUG in ext4_es_cache_extent (2)

Status: upstream: reported C repro on 2025/10/16 22:01
Reported-by: syzbot+535e2f1ec9d23e031cd4@syzkaller.appspotmail.com
First crash: 175d, last: 8d23h
Fix bisection: fixed by (bisect log) :
commit f061f7c331fc16250fc82aa68964f35821687217
Author: Deepanshu Kartikey <kartikey406@gmail.com>
Date: Tue Sep 30 11:28:10 2025 +0000

  ext4: detect invalid INLINE_DATA + EXTENTS flag combination

  
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_es_cache_extent ext4 -1 C inconclusive 6 1141d 1501d 22/29 fixed on 2023/02/24 13:50
android-54 kernel BUG in ext4_es_cache_extent ext4 -1 C 16 607d 1298d 0/2 auto-obsoleted due to no activity on 2024/10/26 14:37
linux-6.1 kernel BUG in ext4_es_cache_extent -1 syz 1 7d05h 7d05h 0/3 upstream: reported syz repro on 2026/03/11 08:55
upstream kernel BUG in ext4_es_cache_extent (4) ext4 -1 C error 15 7d18h 37d 0/29 upstream: reported C repro on 2026/02/09 02:08
android-5-15 kernel BUG in ext4_es_cache_extent origin:lts -1 C 7 11d 24d 0/2 upstream: reported C repro on 2026/02/22 03:30
android-5-10 kernel BUG in ext4_es_cache_extent -1 C error 1 1298d 1298d 0/2 closed as invalid on 2022/09/13 19:49
upstream kernel BUG in ext4_es_cache_extent (3) ext4 -1 C 4 181d 195d 29/29 fixed on 2025/11/18 08:45
android-6-1 kernel BUG in ext4_es_cache_extent origin:upstream -1 C 11 9d21h 11d 0/2 upstream: reported C repro on 2026/03/06 16:01
upstream kernel BUG in ext4_es_cache_extent (2) ext4 -1 1 418d 414d 0/29 auto-obsoleted due to no activity on 2025/05/03 18:51
Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/02/27 17:23 6m retest repro android13-5.10-lts report log
2025/12/19 11:09 8m retest repro android13-5.10-lts report log
2025/10/31 03:13 23m retest repro android13-5.10-lts report log
2025/10/10 04:12 12m retest repro android13-5.10-lts report log

Sample crash report:
EXT4-fs (loop6): mounted filesystem without journal. Opts: delalloc,data_err=abort,barrier=0x0000000000000003,bsddf,bh,oldalloc,data_err=ignore,nouid32,nobh,user_xattr,nouid32,dioread_nolock,,errors=continue
------------[ cut here ]------------
kernel BUG at fs/ext4/extents_status.c:968!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 784 Comm: syz.6.104 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_es_cache_extent+0x57b/0x5d0 fs/ext4/extents_status.c:968
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 7e 3e d2 ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 fc 72 0c 00 eb 13 e8 55 bd 97 ff <0f> 0b e8 4e bd 97 ff eb 28 e8 47 bd 97 ff 31 f6 65 ff 0d 7a 74 35
RSP: 0018:ffffc90000fd6780 EFLAGS: 00010293
RAX: ffffffff81ccf8fb RBX: 0000000000000034 RCX: ffff88812ca713c0
RDX: 0000000000000000 RSI: 0000000000000034 RDI: 0000000000000032
RBP: ffffc90000fd6888 R08: ffffc90000fd67f7 R09: ffffc90000fd67e0
R10: dffffc0000000000 R11: fffff520001facff R12: ffff88811185a3c8
R13: 47ffffffffffffff R14: 0000000000000032 R15: dffffc0000000000
FS:  000055558719c500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555563b62908 CR3: 000000011645e000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_cache_extents fs/ext4/extents.c:516 [inline]
 __read_extent_tree_block+0x44b/0x790 fs/ext4/extents.c:563
 ext4_find_extent+0x8b9/0xe20 fs/ext4/extents.c:928
 ext4_ext_map_blocks+0x20b/0x5dd0 fs/ext4/extents.c:4160
 ext4_map_blocks+0x985/0x1bd0 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+0x136a/0x2eb0 fs/ext4/inode.c:2873
 do_writepages+0x128/0x280 mm/page-writeback.c:2380
 __filemap_fdatawrite_range+0x2a0/0x350 mm/filemap.c:427
 file_write_and_wait_range+0x8c/0x110 mm/filemap.c:766
 ext4_sync_file+0x1a9/0x9f0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x190/0x1a0 fs/sync.c:202
 generic_write_sync include/linux/fs.h:2920 [inline]
 ext4_buffered_write_iter+0x59b/0x640 fs/ext4/file.c:278
 ext4_file_write_iter+0x53f/0x1980 fs/ext4/file.c:-1
 do_iter_readv_writev+0x478/0x5f0 fs/read_write.c:-1
 do_iter_write+0x189/0x630 fs/read_write.c:866
 vfs_iter_write+0x7d/0xa0 fs/read_write.c:907
 iter_file_splice_write+0x68c/0xcb0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe9/0x120 fs/splice.c:936
 splice_direct_to_actor+0x4cb/0xb30 fs/splice.c:891
 do_splice_direct+0x1c2/0x2d0 fs/splice.c:979
 do_sendfile+0x8df/0x1040 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1304
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fec38f5f799
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:00007fff903705d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fec391d8fa0 RCX: 00007fec38f5f799
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007fec38ff5bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000003ffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fec391d8fac R14: 00007fec391d8fa0 R15: 00007fec391d8fa0
Modules linked in:
---[ end trace 15bffac4812431c9 ]---
RIP: 0010:ext4_es_cache_extent+0x57b/0x5d0 fs/ext4/extents_status.c:968
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 7e 3e d2 ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 fc 72 0c 00 eb 13 e8 55 bd 97 ff <0f> 0b e8 4e bd 97 ff eb 28 e8 47 bd 97 ff 31 f6 65 ff 0d 7a 74 35
RSP: 0018:ffffc90000fd6780 EFLAGS: 00010293
RAX: ffffffff81ccf8fb RBX: 0000000000000034 RCX: ffff88812ca713c0
RDX: 0000000000000000 RSI: 0000000000000034 RDI: 0000000000000032
RBP: ffffc90000fd6888 R08: ffffc90000fd67f7 R09: ffffc90000fd67e0
R10: dffffc0000000000 R11: fffff520001facff R12: ffff88811185a3c8
R13: 47ffffffffffffff R14: 0000000000000032 R15: dffffc0000000000
FS:  000055558719c500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556df5f4e8 CR3: 000000011645e000 CR4: 00000000003506b0
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
2026/03/06 16:18 android13-5.10-lts dad37bbb13a8 41d8037d .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_es_cache_extent
2026/03/09 14:41 android13-5.10-lts 9136079e403a 176bead5 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
2026/03/06 19:12 android13-5.10-lts 9a301c292a32 41d8037d .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
2025/09/23 23:28 android13-5.10-lts 911f602c2237 e667a34f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
2026/03/04 16:02 android13-5.10-lts dad37bbb13a8 e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
2025/11/28 23:32 android13-5.10-lts 9286af17ed5f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
2025/10/16 21:51 android13-5.10-lts 2ece552169c2 19568248 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
* Struck through repros no longer work on HEAD.