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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2021-07-01 20:38:58 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2021-07-05 22:23:25 +1000
commit419ac821766cbdb9fd85872bb3f1a589df05c94c (patch)
tree79a02969e894e08ab580ce374e87fc379b73a761
parentcd5d5e602f502895e47e18cd46804d6d7014e65c (diff)
powerpc/bpf: Fix detecting BPF atomic instructions
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.1625145429.git.naveen.n.rao@linux.vnet.ibm.com
-rw-r--r--arch/powerpc/net/bpf_jit_comp64.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 5cad5b5a7e97..de8595880fee 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -667,7 +667,7 @@ 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);
@@ -689,7 +689,7 @@ 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);