CVE-2021-46945

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ext4: always panic when errors=panic is specified<br /> <br /> Before commit 014c9caa29d3 ("ext4: make ext4_abort() use<br /> __ext4_error()"), the following series of commands would trigger a<br /> panic:<br /> <br /> 1. mount /dev/sda -o ro,errors=panic test<br /> 2. mount /dev/sda -o remount,abort test<br /> <br /> After commit 014c9caa29d3, remounting a file system using the test<br /> mount option "abort" will no longer trigger a panic. This commit will<br /> restore the behaviour immediately before commit 014c9caa29d3.<br /> (However, note that the Linux kernel&amp;#39;s behavior has not been<br /> consistent; some previous kernel versions, including 5.4 and 4.19<br /> similarly did not panic after using the mount option "abort".)<br /> <br /> This also makes a change to long-standing behaviour; namely, the<br /> following series commands will now cause a panic, when previously it<br /> did not:<br /> <br /> 1. mount /dev/sda -o ro,errors=panic test<br /> 2. echo test &gt; /sys/fs/ext4/sda/trigger_fs_error<br /> <br /> However, this makes ext4&amp;#39;s behaviour much more consistent, so this is<br /> a good thing.