syzbot


kernel BUG in ext4_es_cache_extent (4)

Status: upstream: reported C repro on 2026/02/09 02:08
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+ccf1421545dbe5caa20c@syzkaller.appspotmail.com
First crash: 57d, last: 9d15h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ext4?] kernel BUG in ext4_es_cache_extent (4) 8 (17) 2026/03/12 18:05
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 1157d 1516d 22/29 fixed on 2023/02/24 13:50
android-54 kernel BUG in ext4_es_cache_extent ext4 -1 C 16 623d 1314d 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 23d 23d 0/3 upstream: reported syz repro on 2026/03/11 08:55
android-5-15 kernel BUG in ext4_es_cache_extent origin:lts -1 C 7 27d 40d 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 1314d 1314d 0/2 closed as invalid on 2022/09/13 19:49
upstream kernel BUG in ext4_es_cache_extent (3) ext4 -1 C 4 197d 211d 29/29 fixed on 2025/11/18 08:45
android-5-10 kernel BUG in ext4_es_cache_extent (2) -1 C done 7 10d 168d 0/2 upstream: reported C repro on 2025/10/16 22:01
android-6-1 kernel BUG in ext4_es_cache_extent origin:upstream -1 C 11 25d 27d 0/2 upstream: reported C repro on 2026/03/06 16:01
upstream kernel BUG in ext4_es_cache_extent (2) ext4 -1 1 434d 430d 0/29 auto-obsoleted due to no activity on 2025/05/03 18:51
Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/03/24 21:20 28m retest repro upstream report log
2026/03/24 21:20 17m retest repro upstream report log
2026/03/12 17:45 18m ojaswin@linux.ibm.com patch https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev report log
2026/02/19 02:14 24m retest repro linux-next report log
2026/02/11 13:42 3h00m ojaswin@linux.ibm.com patch https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev OK log
2026/02/11 08:29 1h04m ojaswin@linux.ibm.com patch https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev OK log
2026/02/10 20:00 53m ojaswin@linux.ibm.com patch https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev OK log
2026/02/10 12:34 23m ojaswin@linux.ibm.com patch https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev report log
2026/02/10 05:49 30m ojaswin@linux.ibm.com https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git 26f260ce5828fc7897a report log
2026/02/09 19:22 18m ojaswin@linux.ibm.com https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev report log

Sample crash report:
EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #15: comm syz.0.83: ES cache extent failed: add [0,1,177,0x1] conflict with existing [0,1,113,0x2]
EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #15: comm syz.0.83: ES cache extent failed: add [1,15,177,0x1] conflict with existing [1,35,576460752303423487,0x18]
EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #15: comm syz.0.83: ES cache extent failed: add [16,1,177,0x1] conflict with existing [1,35,576460752303423487,0x18]
EXT4-fs warning (device loop0): ext4_es_cache_extent:1082: inode #15: comm syz.0.83: ES cache extent failed: add [17,10,177,0x1] conflict with existing [1,35,576460752303423487,0x18]
------------[ cut here ]------------
kernel BUG at fs/ext4/extents_status.c:1044!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 6296 Comm: syz.0.83 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_es_cache_extent+0x875/0x9e0 fs/ext4/extents_status.c:1044
Code: e1 07 80 c1 03 38 c1 0f 8c 5c fe ff ff 48 8b 7c 24 18 e8 fe ac ad ff e9 4d fe ff ff e8 a4 6e 43 ff 90 0f 0b e8 9c 6e 43 ff 90 <0f> 0b 65 8b 1d e6 98 99 10 bf 07 00 00 00 89 de e8 c6 72 43 ff 83
RSP: 0018:ffffc900049bed20 EFLAGS: 00010293
RAX: ffffffff82822744 RBX: 0000000000000018 RCX: ffff88803211bd00
RDX: 0000000000000000 RSI: 000000000000001b RDI: 0000000000000018
RBP: ffffc900049bee68 R08: ffffc900049bedd7 R09: ffffc900049bedc0
R10: dffffc0000000000 R11: fffff52000937dbb R12: ffffc900049bedc0
R13: 000000000000001b R14: 000000000000000f R15: dffffc0000000000
FS:  00007f2dad5066c0(0000) GS:ffff888125564000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000c000 CR3: 0000000072fbc000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_cache_extents fs/ext4/extents.c:539 [inline]
 __read_extent_tree_block+0x4b4/0x890 fs/ext4/extents.c:586
 ext4_find_extent+0x76f/0xcc0 fs/ext4/extents.c:939
 ext4_ext_map_blocks+0x283/0x58b0 fs/ext4/extents.c:4261
 ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616
 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809
 _ext4_get_block+0x1e3/0x470 fs/ext4/inode.c:909
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:942
 ext4_block_write_begin+0xb14/0x1950 fs/ext4/inode.c:1196
 ext4_write_begin+0xb40/0x18c0 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x355/0xd80 fs/ext4/inode.c:3123
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314
 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:300
 ext4_file_write_iter+0x298/0x1bf0 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_pwrite64 fs/read_write.c:795 [inline]
 __do_sys_pwrite64 fs/read_write.c:803 [inline]
 __se_sys_pwrite64 fs/read_write.c:800 [inline]
 __x64_sys_pwrite64+0x199/0x230 fs/read_write.c:800
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2dac59c799
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:00007f2dad506028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f2dac815fa0 RCX: 00007f2dac59c799
RDX: 00000000200000c1 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f2dac632bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000009000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2dac816038 R14: 00007f2dac815fa0 R15: 00007ffeaeb86308
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_es_cache_extent+0x875/0x9e0 fs/ext4/extents_status.c:1044
Code: e1 07 80 c1 03 38 c1 0f 8c 5c fe ff ff 48 8b 7c 24 18 e8 fe ac ad ff e9 4d fe ff ff e8 a4 6e 43 ff 90 0f 0b e8 9c 6e 43 ff 90 <0f> 0b 65 8b 1d e6 98 99 10 bf 07 00 00 00 89 de e8 c6 72 43 ff 83
RSP: 0018:ffffc900049bed20 EFLAGS: 00010293
RAX: ffffffff82822744 RBX: 0000000000000018 RCX: ffff88803211bd00
RDX: 0000000000000000 RSI: 000000000000001b RDI: 0000000000000018
RBP: ffffc900049bee68 R08: ffffc900049bedd7 R09: ffffc900049bedc0
R10: dffffc0000000000 R11: fffff52000937dbb R12: ffffc900049bedc0
R13: 000000000000001b R14: 000000000000000f R15: dffffc0000000000
FS:  00007f2dad5066c0(0000) GS:ffff888125564000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000c000 CR3: 0000000072fbc000 CR4: 0000000000350ef0

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/03 19:23 upstream af4e9ef3d784 4180d919 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 19:18 upstream af4e9ef3d784 4180d919 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/02/05 02:01 linux-next 0f8a890c4524 ea10c935 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-linux-next-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/10 19:32 upstream 1f318b96cc84 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root kernel BUG in ext4_es_cache_extent
2026/03/05 22:04 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/05 15:23 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 19:28 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 19:27 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 19:27 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 19:27 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 17:43 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 17:31 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 16:25 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 16:25 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
2026/03/03 16:19 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in ext4_es_cache_extent
* Struck through repros no longer work on HEAD.