CVE-2026-43065— ext4: always drain queued discard work in ext4_mb_release()

ext4: always drain queued discard work in ext4_mb_release()

In the Linux kernel, the following vulnerability has been resolved: ext4: always drain queued discard work in ext4_mb_release() While reviewing recent ext4 patch[1], Sashiko raised the following concern[2]: > If the filesystem is initially mounted with the discard option, > deleting files will populate sbi->s_discard_list and queue > s_discard_work. If it is then remounted with nodiscard, the > EXT4_MOUNT_DISCARD flag is cleared, but the pending s_discard_work is > neither cancelled nor flushed. [1] https://lore.kernel.org/r/20260319094545.19291-1-qiang.zhang@linux.dev/ [2] https://sashiko.dev/#/patchset/20260319094545.19291-1-qiang.zhang%40linux.dev The concern was valid, but it had nothing to do with the patch[1]. One of the problems with Sashiko in its current (early) form is that it will detect pre-existing issues and report it as a problem with the patch that it is reviewing. In practice, it would be hard to hit deliberately (unless you are a malicious syzkaller fuzzer), since it would involve mounting the file system with -o discard, and then deleting a large number of files, remounting the file system with -o nodiscard, and then immediately unmounting the file system before the queued discard work has a change to drain on its own. Fix it because it's a real bug, and to avoid Sashiko from raising this concern when analyzing future patches to mballoc.c.

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Linux kernel 安全漏洞

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ext4文件系统在重新挂载为nodiscard后未排空待处理的丢弃工作。

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