Bug 5576 - fix race condition when computing ocontext SIDs
Summary: fix race condition when computing ocontext SIDs
Status: NEW
Alias: None
Product: ANCK 4.19 Dev
Classification: ANCK
Component: general/others (show other bugs) general/others
Version: unspecified
Hardware: All Linux
: P3-Medium S3-normal
Target Milestone: ---
Assignee: maqiao
QA Contact: shuming
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Reported: 2023-06-20 19:42 UTC by gcc_2023
Modified: 2023-06-21 11:42 UTC (History)
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Description gcc_2023 2023-06-20 19:42:55 UTC 
问题现象：
k8s挂载tmpfs文件系统的挂载点（newshm）目录安全下文(system_u:object_r:adjtime_t:s0)不对, 导致启动容器启动失败。

问题原因：
1、该问题应该上游内核一个bug。大致原因就是就mount tmpfs时候设置tmpfs文件系统的安全上文时，在内核的SID（安全标示）表里去查询对应安全上文里的ID时候，取到CPU的  cached里中间SID值了，所以，导致设置标签不对。已有补丁修解决了该问题，该补丁采用内存屏障来保证cache数据（SID）一致性。
2、补丁链接如下：
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/security/selinux/ss/services.c?h=linux-5.4.y&id=b06b1f46306a5fdcb9da8c9cf59e643a357ff6b8
Comment 1 小龙 admin 2023-06-20 19:46:19 UTC 
The PR Link: https://gitee.com/anolis/cloud-kernel/pulls/1769
Comment 2 小龙 admin 2023-06-21 11:42:28 UTC 
The PR Link: https://gitee.com/anolis/cloud-kernel/pulls/1773