syzbot
kernel BUG in jffs2_sum_write_sumnode (2)
Status:
upstream: reported C repro on 2026/09/06 12:10
Subsystems:
jffs2
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+0727f46a0571de01bf93@syzkaller.appspotmail.com
First crash: 49d, last: 11d
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Last patch testing requests (1)
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Cause bisection attempts (1)
Sample crash report:
block2mtd: Using custom MTD label 'testjffs' for dev /dev/loop0
ftl_cs: FTL header not found.
block2mtd: mtd1: [testjffs] erase_size = 4KiB [4096]
jffs2: notice: (6012) jffs2_build_xattr_subsystem: complete building xattr subsystem, 0 of xdatum (0 unchecked, 0 orphan) and 0 of xref (0 dead, 0 orphan) found.
jffs2: warning: (6012) jffs2_sum_write_sumnode: Empty summary info!!!
------------[ cut here ]------------
kernel BUG at fs/jffs2/summary.c:868!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 6012 Comm: syz-executor253 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:jffs2_sum_write_sumnode.cold+0x4e/0x174 fs/jffs2/summary.c:868
Code: 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 2c 01 00 00 8b b3 40 06 00 00 48 c7 c2 80 9d 33 8c 48 c7 c7 80 99 33 8c e8 2d 6e f8 ff 90 <0f> 0b e8 65 49 e2 00 65 4c 8b 3d 45 e4 63 14 b8 ff ff 37 00 48 c1
RSP: 0018:ffffc9000347f9a0 EFLAGS: 00010286
RAX: 0000000000000045 RBX: ffff88802f168000 RCX: 0000000000000000
RDX: 0000000000000045 RSI: ffffffff81ea14b9 RDI: fffff5200068ff25
RBP: ffffc9000347fb20 R08: 0000000000000007 R09: 0000000000000000
R10: 8000000000000000 R11: 0000000000000001 R12: ffff88807b45a080
R13: 0000000000000000 R14: 0000000000000012 R15: 0000000000000000
FS: 0000555557c2d400(0000) GS:ffff888122a44000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ab45d7ad51 CR3: 0000000021ea9000 CR4: 0000000000350ef0
Call Trace:
<TASK>
jffs2_do_reserve_space+0xb94/0xf70 fs/jffs2/nodemgmt.c:392
jffs2_reserve_space+0x605/0xbb0 fs/jffs2/nodemgmt.c:201
jffs2_symlink+0x172/0x1160 fs/jffs2/dir.c:317
vfs_symlink fs/namei.c:5823 [inline]
vfs_symlink+0x178/0x4d0 fs/namei.c:5802
filename_symlinkat+0x2a6/0x560 fs/namei.c:5848
__do_sys_symlink fs/namei.c:5875 [inline]
__se_sys_symlink fs/namei.c:5871 [inline]
__x64_sys_symlink+0x79/0xb0 fs/namei.c:5871
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda09c12537
Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 6a cd 02 00 48 83 c4 18 c3 0f 1f 44 00 00 b8 58 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 d8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc31fc8508 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007ffc31fc85e0 RCX: 00007fda09c12537
RDX: 0000000000000000 RSI: 00007fda09c7eff9 RDI: 00007fda09c7b2b0
RBP: 00007fda09c7ef8c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc31fc85e0
R13: 00007fda09c7efa1 R14: 00007fda09ca7cc0 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:jffs2_sum_write_sumnode.cold+0x4e/0x174 fs/jffs2/summary.c:868
Code: 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 2c 01 00 00 8b b3 40 06 00 00 48 c7 c2 80 9d 33 8c 48 c7 c7 80 99 33 8c e8 2d 6e f8 ff 90 <0f> 0b e8 65 49 e2 00 65 4c 8b 3d 45 e4 63 14 b8 ff ff 37 00 48 c1
RSP: 0018:ffffc9000347f9a0 EFLAGS: 00010286
RAX: 0000000000000045 RBX: ffff88802f168000 RCX: 0000000000000000
RDX: 0000000000000045 RSI: ffffffff81ea14b9 RDI: fffff5200068ff25
RBP: ffffc9000347fb20 R08: 0000000000000007 R09: 0000000000000000
R10: 8000000000000000 R11: 0000000000000001 R12: ffff88807b45a080
R13: 0000000000000000 R14: 0000000000000012 R15: 0000000000000000
FS: 0000555557c2d400(0000) GS:ffff888122944000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ab45d75950 CR3: 0000000021ea9000 CR4: 0000000000350ef0
* Struck through repros no longer work on HEAD.