CVE-2026-92502— ext4 写入回退时清除陈旧 folio xarray 标签漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
在 Linux 内核中，以下漏洞已得到修复： ext4：清除在写回过程中被跳过的 folio 上残留的 xarray 标签 在 模式下，当系统重启期间超级块（superblock）被重新挂载为只读时，写回线程可能在 中触发 ： 随后出现如下警告： 该问题并非每次都能复现，但出现频率较高。 复现步骤： 1. 创建一个具有 8 个 CPU 和 16G 内存的虚拟机（VM）。 2. 设置 模式： 3. 运行 fio 进行随机写测试： 4. 重启虚拟机，并通过以下命令检查控制台输出： 根本原因分析： 在某些情况下，foli
影响版本矩阵 12
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7< f82a4929d0ef7ddf254c1c295ec1dfd24094f2de |
affected |
dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7< a450ab88bfd57b227d72c7a3faad54d16c3fc099 |
affected | ||
dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7< aa0042630b1f7cab735b0a168539281198822586 |
affected | ||
dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7< 43ae387c3ae6a11227d096669ddf883e27a39a11 |
affected | ||
dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7< ec524aae479b4b2078c47492b90ec21200bce434 |
affected | ||
6.2 |
affected | ||
< 6.2 |
unaffected | ||
6.6.157≤ 6.6.* |
unaffected | ||
| … +4 条更多 | |||
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一、 漏洞 CVE-2026-92502 基础信息
漏洞信息
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Vulnerability Title
ext4: clear stale xarray tags on folios skipped during writeback
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
ext4: clear stale xarray tags on folios skipped during writeback
In data=journal mode, the writeback thread can hit the
WARN_ON_ONCE(sb_rdonly(sb)) in ext4_journal_check_start() while the
superblock is being remounted read-only during reboot:
Workqueue: writeback wb_workfn (flush-253:0)
RIP: 0010:ext4_journal_check_start+0x8b/0xd0
Call Trace:
__ext4_journal_start_sb+0x3c/0x1e0
mpage_prepare_extent_to_map+0x4af/0x580
ext4_do_writepages+0x3c0/0x1080
ext4_writepages+0xc8/0x1a0
do_writepages+0xc4/0x180
__writeback_single_inode+0x45/0x2f0
writeback_sb_inodes+0x26b/0x5d0
__writeback_inodes_wb+0x54/0x100
wb_writeback+0x1ac/0x320
wb_workfn+0x394/0x470
And followed by the warning:
EXT4-fs warning (device vda1): ext4_evict_inode:195: inode #6263:
comm (sd-umount): data will be lost
This issue is not reproduced every time, but frequently.
The reproduction step is to create a VM with 8 CPUs, 16G memory and
setup data=journal:
sudo tune2fs -o journal_data /dev/vda1
Run fio:
rm -f fiotest
fio --name=fiotest --rw=randwrite --bs=4k --runtime=6 --ioengine=libaio
--iodepth=256 --numjobs=8 --filename=fiotest --filesize=30G
--group_reporting
Reboot the VM, and check the console output from:
virsh console testvm
But there is no dirty inode, folio_clear_dirty_for_io clears PG_dirty
but leaves tags PAGECACHE_TAG_DIRTY and PAGECACHE_TAG_TOWRITE set which
are only cleared by __folio_start_writeback.
In data=journal mode, jbd2 checkpoints the journalled data to its final
location and clears its own dirty flag without touching folio PG_dirty
or xarray dirty flags.
The commit f4a2b42e7891 ("ext4: fix stale xarray tags after writeback")
fixes when PG_dirty is still set but there is no dirty page.
Another case is PG_dirty is cleared, but PAGECACHE_TAG_DIRTY and
PAGECACHE_TAG_TOWRITE is still set. In this case, writeback thread
checks clean folio and skips it in mpage_prepare_extent_to_map:
if (!folio_test_dirty(folio) ||
...
folio_unlcok(folio);
continue
And never reaches ext4_bio_write_folio where the commit f4a2b42e7891
clears the stale xarray tags. Print debug logs after the filesystem
is remounted read-only:
writepages RDONLY nrpages=2048 dirtytag=1 wbtag=0 towrite=1 sync=0
And all folios are actually clean:
folio idx=3 dirty=0 wb=0 checked=0 dirtybuf=0 jbddirty=0 mapped=1
...
We need to clear the xarray stale tags for such clean folios by
cycling them through writeback in the skip path, the same way
f4a2b42e7891 does in ext4_bio_write_folio.
来源: CVE Program / CVE List V5
CVSS Information
N/A
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
受影响产品
二、漏洞 CVE-2026-92502 的公开POC
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CVE-2026-92502 补丁与修复 (4)
同批安全公告 · Linux · 2026-09-17 · 共 600 条
| CVE-2026-92489 | 9.8 CRITICAL | Linux内核 xfrm 双重释放漏洞 |
| CVE-2026-90235 | 9.8 CRITICAL | 内核sunrpc xprtsock并发读取修复 |
| CVE-2026-90173 | 9.8 CRITICAL | SMB SmbDirect 释放完成队列漏洞 |
| CVE-2026-90104 | 9.8 CRITICAL | NFSv4.1 解码前未清空调用列表 |
| CVE-2026-90151 | 9.8 CRITICAL | NFSv4客户端分配失败回调处理漏洞 |
| CVE-2026-90110 | 9.4 CRITICAL | inetpeer 随机化RB树节点比较 |
| CVE-2026-90230 | 9.1 CRITICAL | Linux内核Nvme-target堆越界读取漏洞 |
| CVE-2026-90414 | 9.1 CRITICAL | IB/isert拒绝声明超出实际接收数据的PDU |
| CVE-2026-90413 | 9.1 CRITICAL | IB/isert 登录PDU数据长度校验漏洞 |
| CVE-2026-90367 | 8.8 HIGH | Linux内核MT7996驱动死锁漏洞 |
| CVE-2026-90329 | 8.8 HIGH | Linux 内核 HID 驱动探测清理同步漏洞 |
| CVE-2026-93189 | 8.8 HIGH | Linux HID核心使用已释放内存漏洞 |
| CVE-2026-90240 | 8.8 HIGH | Linux内核 IOMMU 别名拆除时刷新缓存错误 |
| CVE-2026-90357 | 8.8 HIGH | mt76驱动MT7915无线局域网远程拒绝服务漏洞 |
| CVE-2026-90286 | 8.8 HIGH | AMDGPU GFX6 计算队列PFP使用漏洞 |
| CVE-2026-93042 | 8.8 HIGH | Linux内核dmaengine模块资源耗尽漏洞 |
| CVE-2026-90256 | 8.8 HIGH | Linux Bluetooth L2CAP 远程代码执行漏洞 |
| CVE-2026-90380 | 8.8 HIGH | MT76驱动 mt792x 使用释放后内存漏洞 |
| CVE-2026-90381 | 8.8 HIGH | Linux内核mt76驱动无线信道切换漏洞 |
| CVE-2026-90425 | 8.8 HIGH | Linux内核 5.x 内核漏洞 |
显示前 20 条，共 600 条。 查看全部 → →
IV. Related Vulnerabilities
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