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powerpc: Fix signal handling in backtrace 

Now with read consolidation which uses SYSCALL_CANCEL macro, a frame
pointer is created in the syscall code and this makes the powerpc
backtrace obtain a bogus entry for the signal handling patch.

It is because it does not setup the correct frame pointer register
(r1) based on the saved value from the kernel sigreturn.  It was not
failing because the syscall frame pointer register was the same one
for the next frame (the function that actually called the syscall).

This patch fixes it by setup the next stack frame using the saved
one by the kernel sigreturn.  It fixes tst-backtrace{5,6} from
the read consolidation patch.

Checked on powerpc-linux-gnu and powerpc64le-linux-gnu.

	* sysdeps/powerpc/powerpc32/backtrace.c (is_sigtramp_address): Use
	void* for argument type and use VDSO_SYMBOL macro.
	(is_sigtramp_address_rt): Likewise.
	(__backtrace): Setup expected frame pointer address for signal
	handling.
	* sysdeps/powerpc/powerpc64/backtrace.c (is_sigtramp_address): Use
	void* for argumetn type and use VSDO_SYMBOL macro.
	(__backtrace): Setup expected frame pointer address for signal
	handling.
This commit is contained in:
Adhemerval Zanella 2017-05-08 11:22:20 -03:00
parent 488e08b600
commit 31073a53d8
3 changed files with 30 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
ChangeLog
View File

@ -1,5 +1,15 @@
2016-05-10 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* sysdeps/powerpc/powerpc32/backtrace.c (is_sigtramp_address): Use
void* for argument type and use VDSO_SYMBOL macro.
(is_sigtramp_address_rt): Likewise.
(__backtrace): Setup expected frame pointer address for signal
handling.
* sysdeps/powerpc/powerpc64/backtrace.c (is_sigtramp_address): Use
void* for argumetn type and use VSDO_SYMBOL macro.
(__backtrace): Setup expected frame pointer address for signal
handling.
* sysdeps/unix/sysv/linux/writev.c: New file.
* sysdeps/unix/sysv/linux/readv.c: New file.

17
sysdeps/powerpc/powerpc32/backtrace.c
View File

@ -52,10 +52,10 @@ struct signal_frame_32 {
};
static inline int
is_sigtramp_address (unsigned int nip)
is_sigtramp_address (void *nip)
{
#ifdef SHARED
if (nip == (unsigned int)__vdso_sigtramp32)
if (nip == VDSO_SYMBOL (sigtramp32))
return 1;
#endif
return 0;
@ -69,10 +69,10 @@ struct rt_signal_frame_32 {
};
static inline int
is_sigtramp_address_rt (unsigned int nip)
is_sigtramp_address_rt (void * nip)
{
#ifdef SHARED
if (nip == (unsigned int)__vdso_sigtramp_rt32)
if (nip == VDSO_SYMBOL (sigtramp_rt32))
return 1;
#endif
return 0;
@ -100,20 +100,23 @@ __backtrace (void **array, int size)
/* Check if the symbol is the signal trampoline and get the interrupted
* symbol address from the trampoline saved area. */
if (is_sigtramp_address ((unsigned int)current->return_address))
if (is_sigtramp_address (current->return_address))
{
struct signal_frame_32 *sigframe =
(struct signal_frame_32*) current;
gregset = &sigframe->mctx.gregs;
}
else if (is_sigtramp_address_rt ((unsigned int)current->return_address))
else if (is_sigtramp_address_rt (current->return_address))
{
struct rt_signal_frame_32 *sigframe =
(struct rt_signal_frame_32*) current;
gregset = &sigframe->uc.uc_mcontext.uc_regs->gregs;
}
if (gregset)
array[++count] = (void*)((*gregset)[PT_NIP]);
{
array[++count] = (void*)((*gregset)[PT_NIP]);
current = (void*)((*gregset)[PT_R1]);
}
}
/* It's possible the second-last stack frame can't return

17
sysdeps/powerpc/powerpc64/backtrace.c
View File

@ -16,10 +16,12 @@
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <http://www.gnu.org/licenses/>. */
#include <execinfo.h>
#include <stddef.h>
#include <string.h>
#include <signal.h>
#include <stdint.h>
#include <execinfo.h>
#include <libc-vdso.h>
/* This is the stack layout we see with every stack frame.
@ -37,7 +39,7 @@
struct layout
{
struct layout *next;
long condition_register;
long int condition_register;
void *return_address;
};
@ -47,16 +49,16 @@ struct layout
dummy frame to make it look like it has a caller. */
struct signal_frame_64 {
#define SIGNAL_FRAMESIZE 128
char dummy[SIGNAL_FRAMESIZE];
char dummy[SIGNAL_FRAMESIZE];
struct ucontext uc;
/* We don't care about the rest, since the IP value is at 'uc' field. */
};
static inline int
is_sigtramp_address (unsigned long nip)
is_sigtramp_address (void *nip)
{
#ifdef SHARED
if (nip == (unsigned long)__vdso_sigtramp_rt64)
if (nip == VDSO_SYMBOL (sigtramp_rt64))
return 1;
#endif
return 0;
@ -82,10 +84,11 @@ __backtrace (void **array, int size)
/* Check if the symbol is the signal trampoline and get the interrupted
* symbol address from the trampoline saved area. */
if (is_sigtramp_address ((unsigned long)current->return_address))
if (is_sigtramp_address (current->return_address))
{
struct signal_frame_64 *sigframe = (struct signal_frame_64*) current;
array[++count] = (void*)sigframe->uc.uc_mcontext.gp_regs[PT_NIP];
array[++count] = (void*) sigframe->uc.uc_mcontext.gp_regs[PT_NIP];
current = (void*) sigframe->uc.uc_mcontext.gp_regs[PT_R1];
}
}