syzbot


WARNING in ext4_xattr_inode_lookup_create

Status: upstream: reported C repro on 2024/05/28 15:21
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+fe42a669c87e4a980051@syzkaller.appspotmail.com
First crash: 633d, last: 12d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: BUG: unable to handle kernel NULL pointer dereference in ext4_xattr_set_entry (log)
Repro: C syz .config
  
Discussions (10)
Title Replies (including bot) Last reply
[syzbot] Monthly ext4 report (Jan 2026) 0 (1) 2026/01/30 12:35
[syzbot] Monthly ext4 report (Dec 2025) 0 (1) 2025/12/30 09:52
[syzbot] Monthly ext4 report (Nov 2025) 0 (1) 2025/11/28 21:21
[syzbot] Monthly ext4 report (Oct 2025) 0 (1) 2025/10/29 09:02
[syzbot] Monthly ext4 report (Sep 2025) 0 (1) 2025/09/27 20:43
[syzbot] Monthly ext4 report (Aug 2025) 0 (1) 2025/08/27 08:15
[syzbot] Monthly ext4 report (Jul 2025) 0 (1) 2025/07/27 10:41
[syzbot] Monthly ext4 report (Jun 2025) 0 (1) 2025/06/26 05:37
[PATCH] fs/dcache: fix warning in ext4_xattr_inode_lookup_create 3 (3) 2024/05/29 02:01
[syzbot] [ext4?] WARNING in ext4_xattr_inode_lookup_create 1 (3) 2024/05/29 00:53
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING in ext4_xattr_inode_lookup_create origin:upstream -1 C error 178 48d 253d 0/3 upstream: reported C repro on 2025/06/08 17:41
linux-6.6 WARNING in ext4_xattr_inode_lookup_create origin:upstream -1 C error 18 43d 200d 0/2 upstream: reported C repro on 2025/07/31 23:44
Last patch testing requests (11)
Created Duration User Patch Repo Result
2026/01/25 02:02 23m retest repro upstream report log
2026/01/10 21:33 24m retest repro linux-next report log
2025/12/19 00:30 47m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/12/19 00:30 37m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/12/19 00:30 27m retest repro linux-next report log
2025/12/19 00:30 30m retest repro linux-next report log
2025/12/19 00:30 29m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/12/04 21:22 19m retest repro upstream report log
2025/11/20 15:42 23m retest repro upstream report log
2025/11/20 15:41 23m retest repro upstream report log
2024/05/29 00:14 23m eadavis@qq.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8f6a15f095a6 OK log
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/04/09 11:06 5h09m bisect fix upstream OK (0) job log log

Sample crash report:
EXT4-fs warning (device loop0): ext4_xattr_inode_create:1479: refuse to create EA inode when umounting
------------[ cut here ]------------
1
WARNING: fs/ext4/xattr.c:1480 at ext4_xattr_inode_create fs/ext4/xattr.c:1480 [inline], CPU#0: syz-executor/5990
WARNING: fs/ext4/xattr.c:1480 at ext4_xattr_inode_lookup_create+0xb0c/0x1cf0 fs/ext4/xattr.c:1598, CPU#0: syz-executor/5990
Modules linked in:
CPU: 0 UID: 0 PID: 5990 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:ext4_xattr_inode_create fs/ext4/xattr.c:1480 [inline]
RIP: 0010:ext4_xattr_inode_lookup_create+0xb0c/0x1cf0 fs/ext4/xattr.c:1598
Code: 8b 7c 24 18 e9 7a 03 00 00 e8 a0 b1 30 ff 48 89 df 48 c7 c6 ca 02 c8 8d ba c7 05 00 00 48 c7 c1 00 4a c5 8b e8 55 17 fc ff 90 <0f> 0b 90 49 be 00 00 00 00 00 fc ff df 43 c6 44 34 0e f8 48 c7 c3
RSP: 0018:ffffc90003eaf3e0 EFLAGS: 00010246
RAX: 454882ff88950e00 RBX: ffff888030f4a000 RCX: 454882ff88950e00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90003eaf570 R08: ffffc90003eaf027 R09: 1ffff920007d5e04
R10: dffffc0000000000 R11: fffff520007d5e05 R12: 1ffff920007d5e90
R13: ffff88805c081f78 R14: 0000000000000000 R15: ffff88805c081fa0
FS:  000055555a75d500(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555a778a28 CR3: 00000000764e3000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_xattr_block_set+0x229/0x2ad0 fs/ext4/xattr.c:1918
 ext4_xattr_move_to_block fs/ext4/xattr.c:2669 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2744 [inline]
 ext4_expand_extra_isize_ea+0x12cf/0x1ea0 fs/ext4/xattr.c:2832
 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6349
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6392 [inline]
 __ext4_mark_inode_dirty+0x45c/0x6e0 fs/ext4/inode.c:6470
 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:6502
 __mark_inode_dirty+0x390/0x1320 fs/fs-writeback.c:2595
 mark_inode_dirty_sync include/linux/fs.h:2202 [inline]
 iput+0x3e8/0x1020 fs/inode.c:1987
 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1147
 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1174
 shrink_dcache_tree+0xcf/0x310 fs/dcache.c:-1
 do_one_tree fs/dcache.c:1654 [inline]
 shrink_dcache_for_umount+0xa8/0x1f0 fs/dcache.c:1671
 generic_shutdown_super+0x67/0x2c0 fs/super.c:621
 kill_block_super+0x44/0x90 fs/super.c:1722
 ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7444
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1318
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24ff79c117
Code: a2 c7 05 7c 94 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeac295fe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f24ff80471f RCX: 00007f24ff79c117
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeac2960a0
RBP: 00007ffeac2960a0 R08: 00007ffeac2970a0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeac297130
R13: 00007f24ff80471f R14: 0000000000019d0d R15: 00007ffeac297170
 </TASK>

Crashes (994):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/04 12:51 upstream de0674d9bc69 42b01fab .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/25 07:06 upstream 4ea5af085908 0abd0691 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/08/18 19:49 upstream c17b750b3ad9 1804e95e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/08/18 18:47 upstream c17b750b3ad9 1804e95e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/06/19 12:45 upstream fb4d33ab452e ed3e87f7 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/06/08 08:54 upstream 5b032cac6225 4826c28e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-kasan-badwrites-root WARNING in ext4_xattr_inode_lookup_create
2024/05/24 16:34 upstream 8f6a15f095a6 8f98448e .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root WARNING in ext4_xattr_inode_lookup_create
2025/12/27 16:23 linux-next cc3aa43b44bd d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/10/16 01:13 linux-next 1fdbb3ff1233 19568248 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/10/15 23:54 linux-next 1fdbb3ff1233 19568248 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/07/15 02:42 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ec4801305969 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-gce-arm64 WARNING in ext4_xattr_inode_lookup_create
2024/12/11 07:21 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 146ff2c261f3 cfc402b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-gce-arm64 WARNING in ext4_xattr_inode_lookup_create
2024/09/06 07:55 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci df54f4a16f82 464ac2ed .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-gce-arm64 WARNING in ext4_xattr_inode_lookup_create
2026/01/28 19:50 upstream 1f97d9dcf536 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/12/23 01:16 upstream 9448598b22c5 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/08/17 11:52 upstream 99bade344cfa 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in ext4_xattr_inode_lookup_create
2024/05/24 15:17 upstream 8f6a15f095a6 8f98448e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in ext4_xattr_inode_lookup_create
2025/10/23 10:21 linux-next aaa9c3550b60 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 23:35 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 22:29 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 21:36 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 16:00 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 14:04 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 11:00 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 09:54 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 08:01 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 07:30 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 05:39 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 04:35 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 02:06 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/15 00:30 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 23:17 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 21:59 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 21:46 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 20:13 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 18:44 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 16:25 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 13:30 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 10:35 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 09:05 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/14 05:02 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 20:40 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 19:38 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 10:22 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 07:17 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 02:51 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/13 00:05 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/12 07:04 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 21:03 linux-next 5f540c4aade9 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 17:03 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 15:40 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 12:53 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 09:24 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 06:52 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/11 03:20 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/10 21:07 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/10 08:50 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/09 22:02 linux-next 65dd046ef558 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/09/09 22:01 linux-next 65dd046ef558 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ext4_xattr_inode_lookup_create
2025/12/22 22:53 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in ext4_xattr_inode_lookup_create
* Struck through repros no longer work on HEAD.