On 10/06/16 14:41, Maxim Ostapenko wrote:
On 10/06/16 14:18, Jakub Jelinek wrote:
On Fri, Jun 10, 2016 at 02:12:37PM +0300, Maxim Ostapenko wrote:
gcc/ChangeLog:
2016-06-10 Maxim Ostapenko <m.ostape...@samsung.com>
PR sanitizer/71480
* varasm.c (place_block_symbol): Adjust alignment for asan
protected
STRING_CSTs even if TREE_CONSTANT_POOL_ADDRESS_P.
This is ok.
diff --git a/gcc/testsuite/c-c++-common/asan/pr71480.c
b/gcc/testsuite/c-c++-common/asan/pr71480.c
new file mode 100644
index 0000000..cf08ec6
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr71480.c
@@ -0,0 +1,41 @@
+/* { dg-do compile { target { arm*-*-* powerpc*-*-linux* } } } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern int
+strcmp(const char *s1, const char *s2);
+#ifdef __cplusplus
+}
+#endif
Doesn't just using __builtin_strcmp and leaving out the prototype
work too?
+
+__attribute__ ((noinline, noclone)) int
+foo (char *c)
+{
+ return 1;
+}
+
+__attribute__ ((noinline, noclone)) void
+bar (char *c)
+{
+ return;
+}
+
+int main (void)
+{
+ char tpl[20] = "/tmp/test.XXXXXX";
+ int fd = foo (tpl);
+
+ if (fd == -1)
+ return 1;
+
+ bar (tpl);
+
+ if (strcmp (tpl, "/tmp/test.XXXXXX") == 0)
+ return 1;
+
+ return 0;
+}
+
But more importantly, the scan-assembler stuff is IMHO too fragile.
Agree.
Does the bug reproduce actually at runtime, by asan false positive on
something or missing needed diagnostics?
If you need to add some aligned variable into the block before and/or
after
the STRING_CST, so that it is really misaligned, it shouldn't be that
hard
to do so. And the testcase then should be usable on all architectures.
Jakub
For me it reproduces if compile original testcase from BZ with -O2
-fsanitize=address -fno-omit-frame-pointer with following error in
runtime:
==436==AddressSanitizer CHECK failed:
/home/max/src/tizen/linaro-gcc/libsanitizer/asan/asan_globals.cc:145
"((AddrIsAlignedByGranularity(g->beg))) != (0)" (0x0, 0x0)
#0 0xb5e79763 in __asan::AsanCheckFailed(char const*, int, char
const*, unsigned long long, unsigned long long) (libasan.so.3+0x163763)
#1 0xb5e8436f in __sanitizer::CheckFailed(char const*, int, char
const*, unsigned long long, unsigned long long) (libasan.so.3+0x16e36f)
#2 0xb5d4415f in __asan::RegisterGlobal(__asan_global const*)
(libasan.so.3+0x2e15f)
#3 0xb5d4573b in __asan_register_globals (libasan.so.3+0x2f73b)
#4 0x10ca7 in __libc_csu_init
/home/max/build/v6/sources/glibc/csu/elf-init.c:88
#5 0xb5b877fb in __libc_start_main
/home/max/build/v6/sources/glibc/csu/libc-start.c:24
I'll simplify the original testcase, reproduce the same CHECK failure
and repost the patch.
I rewrote the original testcase as you suggested in BZ and verified that
the problem reproduces w/o the patch and goes away with it. Is it OK now?
-Maxim
gcc/ChangeLog:
2016-06-10 Maxim Ostapenko <m.ostape...@samsung.com>
PR sanitizer/71480
* varasm.c (place_block_symbol): Adjust alignment for asan protected
STRING_CSTs even if TREE_CONSTANT_POOL_ADDRESS_P.
gcc/testsuite/ChangeLog:
2016-06-10 Maxim Ostapenko <m.ostape...@samsung.com>
PR sanitizer/71480
* c-c++-common/asan/pr71480.c: New test.
diff --git a/gcc/testsuite/c-c++-common/asan/pr71480.c b/gcc/testsuite/c-c++-common/asan/pr71480.c
new file mode 100644
index 0000000..3cf2c05
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr71480.c
@@ -0,0 +1,41 @@
+/* { dg-do run } */
+
+__attribute__ ((noinline, noclone)) int
+foo (char *c)
+{
+ return 1;
+}
+
+__attribute__ ((noinline, noclone)) void
+bar (char *c)
+{
+ return;
+}
+
+int main (void)
+{
+ char tpl[20] = "/tmp/test.XXXXXX";
+ char tpl2[20] = "/tmp/test.XXXXXX";
+ int fd = foo (tpl);
+ int fd2 = foo (tpl2);
+ if (fd == -1)
+ {
+ if (fd2 != -1)
+ bar (tpl2);
+ return 1;
+ }
+
+ if (fd2 == -1)
+ return 1;
+
+ bar (tpl);
+ bar (tpl2);
+
+ if (__builtin_strcmp (tpl, "/tmp/test.XXXXXX") != 0)
+ return 1;
+
+ if (__builtin_strcmp (tpl, tpl2) != 0)
+ return 1;
+
+ return 0;
+}
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 4a7124e..de8bcd6 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -7201,7 +7201,11 @@ place_block_symbol (rtx symbol)
if ((flag_sanitize & SANITIZE_ADDRESS)
&& TREE_CODE (DECL_INITIAL (decl)) == STRING_CST
&& asan_protect_global (DECL_INITIAL (decl)))
- size += asan_red_zone_size (size);
+ {
+ size += asan_red_zone_size (size);
+ alignment = MAX (alignment,
+ ASAN_RED_ZONE_SIZE * BITS_PER_UNIT);
+ }
}
else
{
