CVE-2026-53370

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> perf/x86/intel: Improve validation and configuration of ACR masks<br /> <br /> Currently there are several issues on the user space ACR mask validation<br /> and configuration.<br /> - The validation for user space ACR mask (attr.config2) is incomplete,<br /> e.g., the ACR mask could include the index which belongs to another<br /> ACR events group, but it&amp;#39;s not validated.<br /> - An early return on an invalid ACR mask caused all subsequent ACR groups<br /> to be skipped.<br /> - The stale hardware ACR mask (hw.config1) is not cleared before setting<br /> new hardware ACR mask.<br /> <br /> The following changes address all of the above issues.<br /> - Figure out the event index group of an ACR group. Any bits in the<br /> user-space mask not present in the index group are now dropped.<br /> - Instead of an early return on invalid bits, drop only the invalid<br /> portions and continue iterating through all ACR events to ensure full<br /> configuration.<br /> - Explicitly clear the stale hardware ACR mask for each event prior to<br /> writing the new configuration.<br /> <br /> Besides, a non-leader event member of ACR group could be disabled in<br /> theory. This could cause bit-shifting errors in the acr_mask of remaining<br /> group members. But since ACR sampling requires all events to be active,<br /> this should not be a big concern in real use case. Add a "FIXME" comment<br /> to notice this risk.