From: Jiri Olsa <[email protected]>
By adding following objects:
bench/mem-memset-x86-64-asm.o
bench/mem-memcpy-x86-64-asm.o
the x86_64 perf binary ended up with executable stack.
The reason was that above objects are assembler sourced and are missing the
GNU-stack note section. In such case the linker assumes that the final binary
should not be restricted at all and mark the stack as RWX.
Adding section ".note.GNU-stack" definition to mentioned objects, with all
flags disabled, thus omiting those objects from linker stack flags decision.
Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=783570
Reported-by: Clark Williams <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Cc: Corey Ashford <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jiri Olsa <[email protected]>
[ committer note: Remaining bits after what was already added to perf/urgent ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/bench/mem-memset-x86-64-asm.S | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/tools/perf/bench/mem-memset-x86-64-asm.S b/tools/perf/bench/mem-memset-x86-64-asm.S
index cb92170..9e5af89 100644
--- a/tools/perf/bench/mem-memset-x86-64-asm.S
+++ b/tools/perf/bench/mem-memset-x86-64-asm.S
@@ -4,3 +4,10 @@
#define Lmemset_c globl memset_c; memset_c
#define Lmemset_c_e globl memset_c_e; memset_c_e
#include "../../../arch/x86/lib/memset_64.S"
+
+/*
+ * We need to provide note.GNU-stack section, saying that we want
+ * NOT executable stack. Otherwise the final linking will assume that
+ * the ELF stack should not be restricted at all and set it RWX.
+ */
+.section .note.GNU-stack,"",@progbits
--
1.7.9.123.g65da0