CVE-2021-47317

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> powerpc/bpf: Fix detecting BPF atomic instructions<br /> <br /> Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other<br /> atomics in .imm") converted BPF_XADD to BPF_ATOMIC and added a way to<br /> distinguish instructions based on the immediate field. Existing JIT<br /> implementations were updated to check for the immediate field and to<br /> reject programs utilizing anything more than BPF_ADD (such as BPF_FETCH)<br /> in the immediate field.<br /> <br /> However, the check added to powerpc64 JIT did not look at the correct<br /> BPF instruction. Due to this, such programs would be accepted and<br /> incorrectly JIT&amp;#39;ed resulting in soft lockups, as seen with the atomic<br /> bounds test. Fix this by looking at the correct immediate value.