In the Linux kernel, the following vulnerability has been resolved: bpf: Check pointer type for...

In the Linux kernel, the following vulnerability has been resolved:

bpf: Check pointer type for all atomic RMW paths

Atomic RMW verification records an instruction pointer type only when the current destination is PTR_TO_ARENA. A second path can therefore reach the same instruction with an ordinary pointer without comparing it against the saved arena type.

The post-verification fixup uses the saved type to rewrite the instruction to BPF_PROBE_ATOMIC for every path. Record the actual destination type for all atomic RMW paths so the existing mismatch check rejects incompatible uses of one instruction.