kernel BUG in ext4_es_cache_extent (4)

Status: auto-obsoleted due to no activity on 2026/09/15 14:07
Subsystems: ext4
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+ccf1421545dbe5caa20c@syzkaller.appspotmail.com
First crash: 228d, last: 180d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
48e69326 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ✅ ❓ kernel BUG in ext4_es_cache_extent (4) 2026/05/17 09:50 2026/05/17 09:50 2026/05/17 10:44 de5aae85
▶ ▼ 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 syz, C inconclusive 6 1329d 1688d 22/29 fixed on 2023/02/24 13:50
android-54 kernel BUG in ext4_es_cache_extent ext4 -1 syz, C 16 795d 1485d 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 error 1 194d 194d 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 syz, C error 7 199d 211d 0/2 auto-obsoleted due to no activity on 2026/09/01 07:59
android-5-10 kernel BUG in ext4_es_cache_extent -1 syz, C error 1 1485d 1485d 0/2 closed as invalid on 2022/09/13 19:49
upstream kernel BUG in ext4_es_cache_extent (3) ext4 -1 syz, C 4 368d 382d 29/29 fixed on 2025/11/18 08:45
android-5-10 kernel BUG in ext4_es_cache_extent (2) -1 syz, C done 9 162d 339d 0/2 auto-obsoleted due to no activity on 2026/08/28 15:54
android-6-1 kernel BUG in ext4_es_cache_extent origin:upstream missing-backport -1 syz, C error 11 152d 199d 0/2 auto-obsoleted due to no activity on 2026/09/19 12:03
upstream kernel BUG in ext4_es_cache_extent (2) ext4 -1 1 606d 602d 0/29 auto-obsoleted due to no activity on 2025/05/03 18:51
▶ ▼ Last patch testing requests (15)
Created Duration User Patch Repo Result
2026/09/15 13:30 36m retest repro upstream no crash job log log
2026/08/14 23:46 1h47m retest repro upstream no crash job log log
2026/07/04 13:20 27m retest repro upstream log
2026/06/02 21:47 25m retest repro upstream log
2026/05/02 05:46 46m retest repro linux-next no crash log
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 loop2): ext4_es_cache_extent:1079: inode #18: comm syz.2.2047: ES cache extent failed: add [58,6,250,0x2] conflict with existing [27,-28,576460752303423487,0x18]
------------[ cut here ]------------
kernel BUG at fs/ext4/extents_status.c:1044!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 14513 Comm: syz.2.2047 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_es_cache_extent+0x6ed/0x7e0 fs/ext4/extents_status.c:1044
Code: 24 28 e8 46 f6 15 00 48 83 c4 30 e9 ad fa ff ff e8 98 8f a9 ff e9 87 fa ff ff e8 be 8f a9 ff e9 28 fc ff ff e8 04 01 3e ff 90 <0f> 0b e8 fc 00 3e ff 90 0f 0b 90 e9 20 fd ff ff e8 ee 00 3e ff 49
RSP: 0018:ffffc9000547ebd0 EFLAGS: 00010287
RAX: 000000000005b036 RBX: 1ffff92000a8fd7f RCX: ffffc90010152000
RDX: 0000000000080000 RSI: ffffffff82ca983c RDI: ffff8880281e9e80
RBP: ffff8880587cec20 R08: 0000000000000004 R09: 0000000000000040
R10: 000000000000002f R11: 0000000000000000 R12: 0000000000000040
R13: 00000000fffffff0 R14: 0000000000000008 R15: 0000000000000001
FS:  00007f5eca7d56c0(0000) GS:ffff888124448000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000197030 CR3: 000000007da7d000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_cache_extents+0x236/0x2e0 fs/ext4/extents.c:539
 __read_extent_tree_block+0x540/0x670 fs/ext4/extents.c:586
 ext4_find_extent+0x510/0xa30 fs/ext4/extents.c:939
 ext4_ext_map_blocks+0x20a/0x59a0 fs/ext4/extents.c:4261
 ext4_map_create_blocks+0xec/0x5e0 fs/ext4/inode.c:616
 ext4_map_blocks+0x46b/0xd30 fs/ext4/inode.c:809
 _ext4_get_block+0x250/0x5a0 fs/ext4/inode.c:909
 ext4_get_block_unwritten+0x29/0x110 fs/ext4/inode.c:942
 ext4_block_write_begin+0x7fd/0x1530 fs/ext4/inode.c:1196
 ext4_write_begin+0x919/0x1820 fs/ext4/inode.c:1357
 ext4_da_write_begin+0x2a7/0xd70 fs/ext4/inode.c:3123
 generic_perform_write+0x292/0xa40 mm/filemap.c:4319
 ext4_buffered_write_iter+0x119/0x440 fs/ext4/file.c:300
 ext4_file_write_iter+0xa2f/0x1d40 fs/ext4/file.c:719
 iter_file_splice_write+0x830/0x10a0 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x192/0x6c0 fs/splice.c:1159
 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x174/0x240 fs/splice.c:1228
 do_sendfile+0xadc/0xe20 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1419
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ecc59c799
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:00007f5eca7d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f5ecc816090 RCX: 00007f5ecc59c799
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007f5ecc632c99 R08: 0000000000000000 R09: 0000000000000000
R10: 000000007ffff000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ecc816128 R14: 00007f5ecc816090 R15: 00007ffda0bc3788
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_es_cache_extent+0x6ed/0x7e0 fs/ext4/extents_status.c:1044
Code: 24 28 e8 46 f6 15 00 48 83 c4 30 e9 ad fa ff ff e8 98 8f a9 ff e9 87 fa ff ff e8 be 8f a9 ff e9 28 fc ff ff e8 04 01 3e ff 90 <0f> 0b e8 fc 00 3e ff 90 0f 0b 90 e9 20 fd ff ff e8 ee 00 3e ff 49
RSP: 0018:ffffc9000547ebd0 EFLAGS: 00010287
RAX: 000000000005b036 RBX: 1ffff92000a8fd7f RCX: ffffc90010152000
RDX: 0000000000080000 RSI: ffffffff82ca983c RDI: ffff8880281e9e80
RBP: ffff8880587cec20 R08: 0000000000000004 R09: 0000000000000040
R10: 000000000000002f R11: 0000000000000000 R12: 0000000000000040
R13: 00000000fffffff0 R14: 0000000000000008 R15: 0000000000000001
FS:  00007f5eca7d56c0(0000) GS:ffff888124448000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0bd9703e9c CR3: 000000007da7d000 CR4: 0000000000350ef0

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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 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
2026/03/03 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
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
* Struck through repros no longer work on HEAD.