Re: [PATCH v2] cxl/events: Test CME counter expiry with equality, not bitwise AND

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 22 Sep 2026 16:22:14 +0800
Guixin Liu <kanie@linux.alibaba.com> wrote:

> The Memory Event Type field in the General Media and DRAM event records
> is an enumeration, not a bitmask. The validity checks for the advanced
> programmable CME counter expiration event (05h) test the field with a
> bitwise AND, so types 01h, 03h, 04h and 06h match it as well.
> 
> A device reporting one of those types trips WARN_ON_ONCE once the
> general media or DRAM tracepoint is enabled, which is the case anywhere
> rasdaemon collects CXL events. Under panic_on_warn=1 that kills the
> machine.
> 
> Compare the type field for equality instead. Type 05h records that do
> violate the spec conditions still warn.
> 
> Fixes: cd3b36cfc659 ("cxl/events: Add extra validity checks for corrected memory error count in General Media Event Record")
> Fixes: d8145bb8af5c ("cxl/events: Add extra validity checks for CVME count in DRAM Event Record")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>