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authorDavid S. Miller <davem@davemloft.net>2018-04-25 22:55:33 -0400
committerDavid S. Miller <davem@davemloft.net>2018-04-25 22:55:33 -0400
commit25eb0ea7174c6e84f21fa59dccbddd0318b17b12 (patch)
tree07ecdbd7810e448e3b744c0ef143480a6c4e129d /arch/x86
parent91a825290ca4eae88603bc811bf74a45f94a3f46 (diff)
parent9c299a32ede98dc9faafb267034ed830a15304db (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says: ==================== pull-request: bpf 2018-04-25 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Fix to clear the percpu metadata_dst that could otherwise carry stale ip_tunnel_info, from William. 2) Fix that reduces the number of passes in x64 JIT with regards to dead code sanitation to avoid risk of prog rejection, from Gianluca. 3) Several fixes of sockmap programs, besides others, fixing a double page_put() in error path, missing refcount hold for pinned sockmap, adding required -target bpf for clang in sample Makefile, from John. 4) Fix to disable preemption in __BPF_PROG_RUN_ARRAY() paths, from Roman. 5) Fix tools/bpf/ Makefile with regards to a lex/yacc build error seen on older gcc-5, from John. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/net/bpf_jit_comp.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index b725154182cc..abce27ceb411 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1027,7 +1027,17 @@ emit_cond_jmp: /* convert BPF opcode to x86 */
break;
case BPF_JMP | BPF_JA:
- jmp_offset = addrs[i + insn->off] - addrs[i];
+ if (insn->off == -1)
+ /* -1 jmp instructions will always jump
+ * backwards two bytes. Explicitly handling
+ * this case avoids wasting too many passes
+ * when there are long sequences of replaced
+ * dead code.
+ */
+ jmp_offset = -2;
+ else
+ jmp_offset = addrs[i + insn->off] - addrs[i];
+
if (!jmp_offset)
/* optimize out nop jumps */
break;