Naveen N. Rao wrote:
Since BPF constant blinding is performed after the verifier pass, there are certain ALU32 instructions inserted which don't have a corresponding zext instruction inserted after. This is causing a kernel oops on powerpc and can be reproduced by running 'test_cgroup_storage' with bpf_jit_harden=2.Fix this by emitting BPF_ZEXT during constant blinding if prog->aux->verifier_zext is set. Fixes: a4b1d3c1ddf6cb ("bpf: verifier: insert zero extension according to analysis result") Reported-by: Michael Ellerman <[email protected]> Signed-off-by: Naveen N. Rao <[email protected]> ---This approach (the location where zext is being introduced below, in particular) works for powerpc, but I am not entirely sure if this is sufficient for other architectures as well. This is broken on v5.3-rc4.
Alexie, Daniel, Jiong, Any feedback on this? - Naveen
