From: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com
[ Upstream commit 419ac821766cbdb9fd85872bb3f1a589df05c94c ]
Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other atomics in .imm") converted BPF_XADD to BPF_ATOMIC and added a way to distinguish instructions based on the immediate field. Existing JIT implementations were updated to check for the immediate field and to reject programs utilizing anything more than BPF_ADD (such as BPF_FETCH) in the immediate field.
However, the check added to powerpc64 JIT did not look at the correct BPF instruction. Due to this, such programs would be accepted and incorrectly JIT'ed resulting in soft lockups, as seen with the atomic bounds test. Fix this by looking at the correct immediate value.
Fixes: 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other atomics in .imm") Reported-by: Jiri Olsa jolsa@redhat.com Signed-off-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com Tested-by: Jiri Olsa jolsa@redhat.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/4117b430ffaa8cd7af042496f87fd7539e4f17fd.162514542... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/net/bpf_jit_comp64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index aaf1a887f653..2657bf542985 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -686,7 +686,7 @@ emit_clear: * BPF_STX ATOMIC (atomic ops) */ case BPF_STX | BPF_ATOMIC | BPF_W: - if (insn->imm != BPF_ADD) { + if (imm != BPF_ADD) { pr_err_ratelimited( "eBPF filter atomic op code %02x (@%d) unsupported\n", code, i); @@ -708,7 +708,7 @@ emit_clear: PPC_BCC_SHORT(COND_NE, tmp_idx); break; case BPF_STX | BPF_ATOMIC | BPF_DW: - if (insn->imm != BPF_ADD) { + if (imm != BPF_ADD) { pr_err_ratelimited( "eBPF filter atomic op code %02x (@%d) unsupported\n", code, i);