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-rw-r--r--tests/ChangeLog16
-rw-r--r--tests/backtrace-child.c18
-rw-r--r--tests/backtrace.c39
3 files changed, 51 insertions, 22 deletions
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 1d8c5b0b..2e9aa0d0 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,19 @@
+2016-08-25 Mark Wielaard <[email protected]>
+
+ * backtrace-child.c: Disable and add documentation about why we disable
+ RAISE_JMP_PATCHING even on x86_64.
+ * backtrace.c (is_x86_64_native): Rename to...
+ (use_raise_jmp_patching): ... this.
+ (callback_verify): Use use_raise_jmp_patching instead of
+ is_x86_64_native.
+ (see_exec_module): Return DWARF_CB_ABORT after finding the correct exe
+ path.
+ (prepare_thread): Use RAISE_JMP_PATCHING instead of __x86_64__
+ conditional.
+ (exec_dump): Only assert on data.mod != NULL. Drop ptrdiff. Use
+ RAISE_JMP_PATCHING instead of __x86_64__ conditional. Use
+ use_raise_jmp_patching instead of is_x86_64_native.
+
2016-08-24 Mark Wielaard <[email protected]>
* Makefile.am (EXTRA_DIST): Add testfilesparc64attrs.o.bz2.
diff --git a/tests/backtrace-child.c b/tests/backtrace-child.c
index 40e7b32d..cf4547ca 100644
--- a/tests/backtrace-child.c
+++ b/tests/backtrace-child.c
@@ -1,5 +1,5 @@
/* Test child for parent backtrace test.
- Copyright (C) 2013 Red Hat, Inc.
+ Copyright (C) 2013, 2016 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -19,7 +19,8 @@
--ptraceme will call ptrace (PTRACE_TRACEME) in the two threads.
--gencore will call abort () at its end.
Main thread will signal SIGUSR2. Other thread will signal SIGUSR1.
- On x86_64 only:
+ There used to be a difference between x86_64 and other architectures.
+ To test getting a signal at the very first instruction of a function:
PC will get changed to function 'jmp' by backtrace.c function
prepare_thread. Then SIGUSR2 will be signalled to backtrace-child
which will invoke function sigusr2.
@@ -66,8 +67,17 @@
# 5 0xf77c1a48 - 1 start
# 6 0xf77699da - 1 start_thread
# 7 0xf769bbfe - 1 __clone
+
+ But the raise jmp patching was unreliable. It depends on the CFI for the raise()
+ function in glibc to be the same as for the jmp() function. This is not always
+ the case. Some newer glibc versions rewrote raise() and now the CFA is calculated
+ differently. So we disable raise jmp patching everywhere.
*/
+#ifdef __x86_64__
+/* #define RAISE_JMP_PATCHING 1 */
+#endif
+
#include <config.h>
#include <assert.h>
#include <stdlib.h>
@@ -130,7 +140,7 @@ dummy1 (void)
asm volatile ("");
}
-#ifdef __x86_64__
+#ifdef RAISE_JMP_PATCHING
static NOINLINE_NOCLONE USED void
jmp (void)
{
@@ -157,7 +167,7 @@ stdarg (int f UNUSED, ...)
assert (errno == 0);
assert (l == 0);
}
-#ifdef __x86_64__
+#ifdef RAISE_JMP_PATCHING
if (! gencore)
{
/* Execution will get PC patched into function jmp. */
diff --git a/tests/backtrace.c b/tests/backtrace.c
index 12476430..2440ab34 100644
--- a/tests/backtrace.c
+++ b/tests/backtrace.c
@@ -1,5 +1,5 @@
/* Test program for unwinding of frames.
- Copyright (C) 2013, 2014 Red Hat, Inc.
+ Copyright (C) 2013, 2014, 2016 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -64,7 +64,7 @@ dump_modules (Dwfl_Module *mod, void **userdata __attribute__ ((unused)),
return DWARF_CB_OK;
}
-static bool is_x86_64_native;
+static bool use_raise_jmp_patching;
static pid_t check_tid;
static void
@@ -93,7 +93,7 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
static bool reduce_frameno = false;
if (reduce_frameno)
frameno--;
- if (! is_x86_64_native && frameno >= 2)
+ if (! use_raise_jmp_patching && frameno >= 2)
frameno += 2;
const char *symname2 = NULL;
switch (frameno)
@@ -112,8 +112,8 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
case 2: // x86_64 only
/* __restore_rt - glibc maybe does not have to have this symbol. */
break;
- case 3: // x86_64 only
- if (is_x86_64_native)
+ case 3: // use_raise_jmp_patching
+ if (use_raise_jmp_patching)
{
/* Verify we trapped on the very first instruction of jmp. */
assert (symname != NULL && strcmp (symname, "jmp") == 0);
@@ -138,7 +138,7 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
// there is no guarantee that the compiler doesn't reorder the
// instructions or even inserts some padding instructions at the end
// (which apparently happens on ppc64).
- if (is_x86_64_native)
+ if (use_raise_jmp_patching)
assert (symname2 == NULL || strcmp (symname2, "backtracegen") != 0);
break;
}
@@ -243,10 +243,10 @@ see_exec_module (Dwfl_Module *mod, void **userdata __attribute__ ((unused)),
return DWARF_CB_OK;
assert (data->mod == NULL);
data->mod = mod;
- return DWARF_CB_OK;
+ return DWARF_CB_ABORT;
}
-/* On x86_64 only:
+/* We used to do this on x86_64 only (see backtrace-child why we now don't):
PC will get changed to function 'jmp' by backtrace.c function
prepare_thread. Then SIGUSR2 will be signalled to backtrace-child
which will invoke function sigusr2.
@@ -254,13 +254,17 @@ see_exec_module (Dwfl_Module *mod, void **userdata __attribute__ ((unused)),
instruction of a function. Properly handled unwind should not slip into
the previous unrelated function. */
+#ifdef __x86_64__
+/* #define RAISE_JMP_PATCHING 1 */
+#endif
+
static void
prepare_thread (pid_t pid2 __attribute__ ((unused)),
void (*jmp) (void) __attribute__ ((unused)))
{
-#ifndef __x86_64__
+#ifndef RAISE_JMP_PATCHING
abort ();
-#else /* x86_64 */
+#else /* RAISE_JMP_PATCHING */
long l;
struct user_regs_struct user_regs;
errno = 0;
@@ -278,7 +282,7 @@ prepare_thread (pid_t pid2 __attribute__ ((unused)),
assert (got == pid2);
assert (WIFSTOPPED (status));
assert (WSTOPSIG (status) == SIGUSR1);
-#endif /* __x86_64__ */
+#endif /* RAISE_JMP_PATCHING */
}
#include <asm/unistd.h>
@@ -370,21 +374,20 @@ exec_dump (const char *exec)
assert (ssize > 0 && ssize < (ssize_t) sizeof (data.selfpath));
data.selfpath[ssize] = '\0';
data.mod = NULL;
- ptrdiff_t ptrdiff = dwfl_getmodules (dwfl, see_exec_module, &data, 0);
- assert (ptrdiff == 0);
+ dwfl_getmodules (dwfl, see_exec_module, &data, 0);
assert (data.mod != NULL);
GElf_Addr loadbase;
Elf *elf = dwfl_module_getelf (data.mod, &loadbase);
GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem);
assert (ehdr != NULL);
/* It is false also on x86_64 with i386 inferior. */
-#ifndef __x86_64__
- is_x86_64_native = false;
-#else /* __x86_64__ */
- is_x86_64_native = ehdr->e_machine == EM_X86_64;
+#ifndef RAISE_JMP_PATCHING
+ use_raise_jmp_patching = false;
+#else /* RAISE_JMP_PATCHING_ */
+ use_raise_jmp_patching = ehdr->e_machine == EM_X86_64;
#endif /* __x86_64__ */
void (*jmp) (void) = 0;
- if (is_x86_64_native)
+ if (use_raise_jmp_patching)
{
// Find inferior symbol named "jmp".
int nsym = dwfl_module_getsymtab (data.mod);
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-19 05:37:00 +0000