CVE-2025-38008

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/page_alloc: fix race condition in unaccepted memory handling<br /> <br /> The page allocator tracks the number of zones that have unaccepted memory<br /> using static_branch_enc/dec() and uses that static branch in hot paths to<br /> determine if it needs to deal with unaccepted memory.<br /> <br /> Borislav and Thomas pointed out that the tracking is racy: operations on<br /> static_branch are not serialized against adding/removing unaccepted pages<br /> to/from the zone.<br /> <br /> Sanity checks inside static_branch machinery detects it:<br /> <br /> WARNING: CPU: 0 PID: 10 at kernel/jump_label.c:276 __static_key_slow_dec_cpuslocked+0x8e/0xa0<br /> <br /> The comment around the WARN() explains the problem:<br /> <br /> /*<br /> * Warn about the &amp;#39;-1&amp;#39; case though; since that means a<br /> * decrement is concurrent with a first (0-&gt;1) increment. IOW<br /> * people are trying to disable something that wasn&amp;#39;t yet fully<br /> * enabled. This suggests an ordering problem on the user side.<br /> */<br /> <br /> The effect of this static_branch optimization is only visible on<br /> microbenchmark.<br /> <br /> Instead of adding more complexity around it, remove it altogether.