diff mbox series

[v2,1/1] ptrace07: should not use a hard-coded xstate size and use CPUID specified instead

Message ID 466821336a63ab9b6c236a0a1c4dbe056b7a5ac3.1664418361.git.pengfei.xu@intel.com
State Changes Requested
Headers show
Series [v2,1/1] ptrace07: should not use a hard-coded xstate size and use CPUID specified instead | expand

Commit Message

Pengfei Xu Sept. 29, 2022, 2:30 a.m. UTC 
Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
it will cause the ptrace07 case to fail as below:
"
./ptrace07
tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
tst_test.c:1571: TINFO: Killed the leftover descendant processes

Summary:
passed   0
failed   0
broken   1
skipped  0
warnings 0
"

Reported-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
---
 testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

Comments

Pengfei Xu Oct. 14, 2022, 6:38 a.m. UTC | #1 
Hi,

This patch fixes ptrace07 spurious failures when the platform xstate maxium
size is bigger than 4096bytes(512*8 bytes).

Thanks for comments!

BR.

On 2022-09-29 at 10:30:20 +0800, Pengfei Xu wrote:
> Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
> wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
> If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
> it will cause the ptrace07 case to fail as below:
> "
> ./ptrace07
> tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
> ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
> tst_test.c:1571: TINFO: Killed the leftover descendant processes
> 
> Summary:
> passed   0
> failed   0
> broken   1
> skipped  0
> warnings 0
> "
> 
> Reported-by: Eric DeVolder <eric.devolder@oracle.com>
> Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
> Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
> ---
>  testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
> index da62cadb0..0accaceb5 100644
> --- a/testcases/kernel/syscalls/ptrace/ptrace07.c
> +++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
> @@ -35,6 +35,7 @@
>  #include "config.h"
>  #include "ptrace.h"
>  #include "tst_test.h"
> +#include "ltp_cpuid.h"
>  
>  #ifndef PTRACE_GETREGSET
>  # define PTRACE_GETREGSET 0x4204
> @@ -48,6 +49,8 @@
>  # define NT_X86_XSTATE 0x202
>  #endif
>  
> +#define CPUID_LEAF_XSTATE 0xd
> +
>  static void check_regs_loop(uint32_t initval)
>  {
>  	const unsigned long num_iters = 1000000000;
> @@ -83,8 +86,15 @@ static void do_test(void)
>  	int i;
>  	int num_cpus = tst_ncpus();
>  	pid_t pid;
> -	uint64_t xstate[512];
> -	struct iovec iov = { .iov_base = xstate, .iov_len = sizeof(xstate) };
> +	uint32_t eax, ebx, ecx = 0, edx;
> +	uint64_t *xstate;
> +	/*
> +	 * CPUID.(EAX=0DH, ECX=0H):EBX: maximum size (bytes, from the beginning
> +	 * of the XSAVE/XRSTOR save area) required by enabled features in XCR0.
> +	 */
> +	cpuid(CPUID_LEAF_XSTATE, &eax, &ebx, &ecx, &edx);
> +	xstate = aligned_alloc(64, ebx);
> +	struct iovec iov = { .iov_base = xstate, .iov_len = ebx };
>  	int status;
>  	bool okay;
>  
> @@ -102,12 +112,15 @@ static void do_test(void)
>  	sched_yield();
>  
>  	TEST(ptrace(PTRACE_ATTACH, pid, 0, 0));
> -	if (TST_RET != 0)
> +	if (TST_RET != 0) {
> +		free(xstate);
>  		tst_brk(TBROK | TTERRNO, "PTRACE_ATTACH failed");
> +	}
>  
>  	SAFE_WAITPID(pid, NULL, 0);
>  	TEST(ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov));
>  	if (TST_RET != 0) {
> +		free(xstate);
>  		if (TST_ERR == EIO)
>  			tst_brk(TCONF, "GETREGSET/SETREGSET is unsupported");
>  
> @@ -138,6 +151,7 @@ static void do_test(void)
>  		tst_res(TINFO,
>  			"PTRACE_SETREGSET with reserved bits failed with EINVAL");
>  	} else {
> +		free(xstate);
>  		tst_brk(TBROK | TTERRNO,
>  			"PTRACE_SETREGSET failed with unexpected error");
>  	}
> @@ -152,8 +166,10 @@ static void do_test(void)
>  	 * worry about potential stops after this point.
>  	 */
>  	TEST(ptrace(PTRACE_DETACH, pid, 0, 0));
> -	if (TST_RET != 0)
> +	if (TST_RET != 0) {
> +		free(xstate);
>  		tst_brk(TBROK | TTERRNO, "PTRACE_DETACH failed");
> +	}
>  
>  	/* If child 'pid' crashes, only report it as info. */
>  	SAFE_WAITPID(pid, &status, 0);
> @@ -173,6 +189,7 @@ static void do_test(void)
>  	}
>  	if (okay)
>  		tst_res(TPASS, "wasn't able to set invalid FPU state");
> +	free(xstate);
>  }
>  
>  static struct tst_test test = {
> -- 
> 2.31.1
>
Richard Palethorpe Oct. 17, 2022, 1:55 p.m. UTC | #2 
Hello,

Pengfei Xu <pengfei.xu@intel.com> writes:

> Hi,
>
> This patch fixes ptrace07 spurious failures when the platform xstate maxium
> size is bigger than 4096bytes(512*8 bytes).
>
> Thanks for comments!

This patch causes the test to fail on my Xeon workstation. The problem
seems to be the cpuid function which just fills the args with zeros.

>
> BR.
>
> On 2022-09-29 at 10:30:20 +0800, Pengfei Xu wrote:
>> Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
>> wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
>> If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
>> it will cause the ptrace07 case to fail as below:
>> "
>> ./ptrace07
>> tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
>> ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
>> tst_test.c:1571: TINFO: Killed the leftover descendant processes
>> 
>> Summary:
>> passed   0
>> failed   0
>> broken   1
>> skipped  0
>> warnings 0
>> "
>> 
>> Reported-by: Eric DeVolder <eric.devolder@oracle.com>
>> Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
>> Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
>> ---
>>  testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
>>  1 file changed, 21 insertions(+), 4 deletions(-)
>> 
>> diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
>> index da62cadb0..0accaceb5 100644
>> --- a/testcases/kernel/syscalls/ptrace/ptrace07.c
>> +++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
>> @@ -35,6 +35,7 @@
>>  #include "config.h"
>>  #include "ptrace.h"
>>  #include "tst_test.h"
>> +#include "ltp_cpuid.h"

This is from the old API (starts with ltp_) so we shouldn't use it
anymore. If it is being used at all, then it's being used in a way that
would allow it to silently fail AFAICT.

>>  
>>  #ifndef PTRACE_GETREGSET
>>  # define PTRACE_GETREGSET 0x4204
>> @@ -48,6 +49,8 @@
>>  # define NT_X86_XSTATE 0x202
>>  #endif
>>  
>> +#define CPUID_LEAF_XSTATE 0xd
>> +
>>  static void check_regs_loop(uint32_t initval)
>>  {
>>  	const unsigned long num_iters = 1000000000;
>> @@ -83,8 +86,15 @@ static void do_test(void)
>>  	int i;
>>  	int num_cpus = tst_ncpus();
>>  	pid_t pid;
>> -	uint64_t xstate[512];
>> -	struct iovec iov = { .iov_base = xstate, .iov_len = sizeof(xstate) };
>> +	uint32_t eax, ebx, ecx = 0, edx;
>> +	uint64_t *xstate;
>> +	/*
>> +	 * CPUID.(EAX=0DH, ECX=0H):EBX: maximum size (bytes, from the beginning
>> +	 * of the XSAVE/XRSTOR save area) required by enabled features in XCR0.
>> +	 */
>> +	cpuid(CPUID_LEAF_XSTATE, &eax, &ebx, &ecx, &edx);
>> +	xstate = aligned_alloc(64, ebx);
>> +	struct iovec iov = { .iov_base = xstate, .iov_len = ebx };
>>  	int status;
>>  	bool okay;

Adding:

tst_res(TINFO, "EAX=%u, ECX=%u, EBX=%u", eax, ecx, ebx);

prints:

ptrace07.c:101: TINFO: EAX=0, ECX=0, EBX=0
Pengfei Xu Oct. 18, 2022, 7:28 a.m. UTC | #3 
Hi Richard,

On 2022-10-17 at 14:55:29 +0100, Richard Palethorpe wrote:
> Hello,
> 
> Pengfei Xu <pengfei.xu@intel.com> writes:
> 
> > Hi,
> >
> > This patch fixes ptrace07 spurious failures when the platform xstate maxium
> > size is bigger than 4096bytes(512*8 bytes).
> >
> > Thanks for comments!
> 
> This patch causes the test to fail on my Xeon workstation. The problem
> seems to be the cpuid function which just fills the args with zeros.
  Sorry, I didn't meet this issue,  I think I should use a new cpuid function.
  Thanks for the report!

> 
> >
> > BR.
> >
> > On 2022-09-29 at 10:30:20 +0800, Pengfei Xu wrote:
> >> Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
> >> wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
> >> If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
> >> it will cause the ptrace07 case to fail as below:
> >> "
> >> ./ptrace07
> >> tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
> >> ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
> >> tst_test.c:1571: TINFO: Killed the leftover descendant processes
> >> 
> >> Summary:
> >> passed   0
> >> failed   0
> >> broken   1
> >> skipped  0
> >> warnings 0
> >> "
> >> 
> >> Reported-by: Eric DeVolder <eric.devolder@oracle.com>
> >> Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
> >> Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
> >> ---
> >>  testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
> >>  1 file changed, 21 insertions(+), 4 deletions(-)
> >> 
> >> diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> index da62cadb0..0accaceb5 100644
> >> --- a/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> +++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> @@ -35,6 +35,7 @@
> >>  #include "config.h"
> >>  #include "ptrace.h"
> >>  #include "tst_test.h"
> >> +#include "ltp_cpuid.h"
> 
> This is from the old API (starts with ltp_) so we shouldn't use it
> anymore. If it is being used at all, then it's being used in a way that
> would allow it to silently fail AFAICT.
> 
  Thanks for the comments, I plan to add below __cpuid_count() macro function
as below in ltp/include/tst_cpu.h first, there seems to be some other place to
use the cpuid function.

/*
 * gcc cpuid.h provides __cpuid_count() since v4.4.
 * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
 *
 * Provide local define for tests needing __cpuid_count() because
 * ltp needs to work in older environments that do not yet
 * have __cpuid_count().
 */
#ifndef __cpuid_count
#define __cpuid_count(level, count, a, b, c, d)				\
	({								\
	__asm__ __volatile__ ("cpuid\n\t"				\
			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
			      : "0" (level), "2" (count));		\
	})
#endif


> >>  
> >>  #ifndef PTRACE_GETREGSET
> >>  # define PTRACE_GETREGSET 0x4204
> >> @@ -48,6 +49,8 @@
> >>  # define NT_X86_XSTATE 0x202
> >>  #endif
> >>  
> >> +#define CPUID_LEAF_XSTATE 0xd
> >> +
> >>  static void check_regs_loop(uint32_t initval)
> >>  {
> >>  	const unsigned long num_iters = 1000000000;
> >> @@ -83,8 +86,15 @@ static void do_test(void)
> >>  	int i;
> >>  	int num_cpus = tst_ncpus();
> >>  	pid_t pid;
> >> -	uint64_t xstate[512];
> >> -	struct iovec iov = { .iov_base = xstate, .iov_len = sizeof(xstate) };
> >> +	uint32_t eax, ebx, ecx = 0, edx;
> >> +	uint64_t *xstate;
> >> +	/*
> >> +	 * CPUID.(EAX=0DH, ECX=0H):EBX: maximum size (bytes, from the beginning
> >> +	 * of the XSAVE/XRSTOR save area) required by enabled features in XCR0.
> >> +	 */
> >> +	cpuid(CPUID_LEAF_XSTATE, &eax, &ebx, &ecx, &edx);
> >> +	xstate = aligned_alloc(64, ebx);
> >> +	struct iovec iov = { .iov_base = xstate, .iov_len = ebx };
> >>  	int status;
> >>  	bool okay;
> 
> Adding:
> 
> tst_res(TINFO, "EAX=%u, ECX=%u, EBX=%u", eax, ecx, ebx);
> 
  Thanks, I will add it.

Thanks!
BR.

> prints:
> 
> ptrace07.c:101: TINFO: EAX=0, ECX=0, EBX=0
> 
> 
> -- 
> Thank you,
> Richard.
Richard Palethorpe Oct. 18, 2022, 8:11 a.m. UTC | #4 
Hello,

Pengfei Xu <pengfei.xu@intel.com> writes:

> Hi Richard,
>
> On 2022-10-17 at 14:55:29 +0100, Richard Palethorpe wrote:
>> Hello,
>> 
>> Pengfei Xu <pengfei.xu@intel.com> writes:
>> 
>> > Hi,
>> >
>> > This patch fixes ptrace07 spurious failures when the platform xstate maxium
>> > size is bigger than 4096bytes(512*8 bytes).
>> >
>> > Thanks for comments!
>> 
>> This patch causes the test to fail on my Xeon workstation. The problem
>> seems to be the cpuid function which just fills the args with zeros.
>   Sorry, I didn't meet this issue,  I think I should use a new cpuid function.
>   Thanks for the report!
>
>> 
>> >
>> > BR.
>> >
>> > On 2022-09-29 at 10:30:20 +0800, Pengfei Xu wrote:
>> >> Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
>> >> wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
>> >> If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
>> >> it will cause the ptrace07 case to fail as below:
>> >> "
>> >> ./ptrace07
>> >> tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
>> >> ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
>> >> tst_test.c:1571: TINFO: Killed the leftover descendant processes
>> >> 
>> >> Summary:
>> >> passed   0
>> >> failed   0
>> >> broken   1
>> >> skipped  0
>> >> warnings 0
>> >> "
>> >> 
>> >> Reported-by: Eric DeVolder <eric.devolder@oracle.com>
>> >> Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
>> >> Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
>> >> ---
>> >>  testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
>> >>  1 file changed, 21 insertions(+), 4 deletions(-)
>> >> 
>> >> diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
>> >> index da62cadb0..0accaceb5 100644
>> >> --- a/testcases/kernel/syscalls/ptrace/ptrace07.c
>> >> +++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
>> >> @@ -35,6 +35,7 @@
>> >>  #include "config.h"
>> >>  #include "ptrace.h"
>> >>  #include "tst_test.h"
>> >> +#include "ltp_cpuid.h"
>> 
>> This is from the old API (starts with ltp_) so we shouldn't use it
>> anymore. If it is being used at all, then it's being used in a way that
>> would allow it to silently fail AFAICT.
>> 
>   Thanks for the comments, I plan to add below __cpuid_count() macro function
> as below in ltp/include/tst_cpu.h first, there seems to be some other place to
> use the cpuid function.
>
> /*
>  * gcc cpuid.h provides __cpuid_count() since v4.4.
>  * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
>  *
>  * Provide local define for tests needing __cpuid_count() because
>  * ltp needs to work in older environments that do not yet
>  * have __cpuid_count().
>  */
> #ifndef __cpuid_count
> #define __cpuid_count(level, count, a, b, c, d)				\
> 	({								\
> 	__asm__ __volatile__ ("cpuid\n\t"				\
> 			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
> 			      : "0" (level), "2" (count));		\
> 	})
> #endif

Looks good. Although this should go in ltp/include/lapi/cpuid.h as this
is where we put system header fallbacks.
Pengfei Xu Oct. 18, 2022, 8:49 a.m. UTC | #5 
Hi Richard,

On 2022-10-18 at 09:11:47 +0100, Richard Palethorpe wrote:
> Hello,
> 
> Pengfei Xu <pengfei.xu@intel.com> writes:
> 
> > Hi Richard,
> >
> > On 2022-10-17 at 14:55:29 +0100, Richard Palethorpe wrote:
> >> Hello,
> >> 
> >> Pengfei Xu <pengfei.xu@intel.com> writes:
> >> 
> >> > Hi,
> >> >
> >> > This patch fixes ptrace07 spurious failures when the platform xstate maxium
> >> > size is bigger than 4096bytes(512*8 bytes).
> >> >
> >> > Thanks for comments!
> >> 
> >> This patch causes the test to fail on my Xeon workstation. The problem
> >> seems to be the cpuid function which just fills the args with zeros.
> >   Sorry, I didn't meet this issue,  I think I should use a new cpuid function.
> >   Thanks for the report!
> >
> >> 
> >> >
> >> > BR.
> >> >
> >> > On 2022-09-29 at 10:30:20 +0800, Pengfei Xu wrote:
> >> >> Should not use a hard-coded xstate size(512 * 8 = 4096 bytes) which is
> >> >> wrong, should use maximum XSAVE size specified by CPUID.(EAX=0DH, ECX=0H):EBX.
> >> >> If the CPU's maximum XSAVE size exceeds the hard-coded xstate size 4096 bytes,
> >> >> it will cause the ptrace07 case to fail as below:
> >> >> "
> >> >> ./ptrace07
> >> >> tst_test.c:1528: TINFO: Timeout per run is 0h 00m 30s
> >> >> ptrace07.c:142: TBROK: PTRACE_SETREGSET failed with unexpected error: EFAULT (14)
> >> >> tst_test.c:1571: TINFO: Killed the leftover descendant processes
> >> >> 
> >> >> Summary:
> >> >> passed   0
> >> >> failed   0
> >> >> broken   1
> >> >> skipped  0
> >> >> warnings 0
> >> >> "
> >> >> 
> >> >> Reported-by: Eric DeVolder <eric.devolder@oracle.com>
> >> >> Reviewed-by: Chang S. Bae <chang.seok.bae@intel.com>
> >> >> Signed-off-by: Pengfei Xu <pengfei.xu@intel.com>
> >> >> ---
> >> >>  testcases/kernel/syscalls/ptrace/ptrace07.c | 25 +++++++++++++++++----
> >> >>  1 file changed, 21 insertions(+), 4 deletions(-)
> >> >> 
> >> >> diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> >> index da62cadb0..0accaceb5 100644
> >> >> --- a/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> >> +++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
> >> >> @@ -35,6 +35,7 @@
> >> >>  #include "config.h"
> >> >>  #include "ptrace.h"
> >> >>  #include "tst_test.h"
> >> >> +#include "ltp_cpuid.h"
> >> 
> >> This is from the old API (starts with ltp_) so we shouldn't use it
> >> anymore. If it is being used at all, then it's being used in a way that
> >> would allow it to silently fail AFAICT.
> >> 
> >   Thanks for the comments, I plan to add below __cpuid_count() macro function
> > as below in ltp/include/tst_cpu.h first, there seems to be some other place to
> > use the cpuid function.
> >
> > /*
> >  * gcc cpuid.h provides __cpuid_count() since v4.4.
> >  * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
> >  *
> >  * Provide local define for tests needing __cpuid_count() because
> >  * ltp needs to work in older environments that do not yet
> >  * have __cpuid_count().
> >  */
> > #ifndef __cpuid_count
> > #define __cpuid_count(level, count, a, b, c, d)				\
> > 	({								\
> > 	__asm__ __volatile__ ("cpuid\n\t"				\
> > 			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
> > 			      : "0" (level), "2" (count));		\
> > 	})
> > #endif
> 
> Looks good. Although this should go in ltp/include/lapi/cpuid.h as this
> is where we put system header fallbacks.
> 
  Thanks for suggestion! Yes, it's better.
  I will write it in ltp/include/lapi/cpuid.h instead.

  Thanks!
  BR.

> -- 
> Thank you,
> Richard.
diff mbox series

Patch

diff --git a/testcases/kernel/syscalls/ptrace/ptrace07.c b/testcases/kernel/syscalls/ptrace/ptrace07.c
index da62cadb0..0accaceb5 100644
--- a/testcases/kernel/syscalls/ptrace/ptrace07.c
+++ b/testcases/kernel/syscalls/ptrace/ptrace07.c
@@ -35,6 +35,7 @@ 
 #include "config.h"
 #include "ptrace.h"
 #include "tst_test.h"
+#include "ltp_cpuid.h"
 
 #ifndef PTRACE_GETREGSET
 # define PTRACE_GETREGSET 0x4204
@@ -48,6 +49,8 @@ 
 # define NT_X86_XSTATE 0x202
 #endif
 
+#define CPUID_LEAF_XSTATE 0xd
+
 static void check_regs_loop(uint32_t initval)
 {
 	const unsigned long num_iters = 1000000000;
@@ -83,8 +86,15 @@  static void do_test(void)
 	int i;
 	int num_cpus = tst_ncpus();
 	pid_t pid;
-	uint64_t xstate[512];
-	struct iovec iov = { .iov_base = xstate, .iov_len = sizeof(xstate) };
+	uint32_t eax, ebx, ecx = 0, edx;
+	uint64_t *xstate;
+	/*
+	 * CPUID.(EAX=0DH, ECX=0H):EBX: maximum size (bytes, from the beginning
+	 * of the XSAVE/XRSTOR save area) required by enabled features in XCR0.
+	 */
+	cpuid(CPUID_LEAF_XSTATE, &eax, &ebx, &ecx, &edx);
+	xstate = aligned_alloc(64, ebx);
+	struct iovec iov = { .iov_base = xstate, .iov_len = ebx };
 	int status;
 	bool okay;
 
@@ -102,12 +112,15 @@  static void do_test(void)
 	sched_yield();
 
 	TEST(ptrace(PTRACE_ATTACH, pid, 0, 0));
-	if (TST_RET != 0)
+	if (TST_RET != 0) {
+		free(xstate);
 		tst_brk(TBROK | TTERRNO, "PTRACE_ATTACH failed");
+	}
 
 	SAFE_WAITPID(pid, NULL, 0);
 	TEST(ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov));
 	if (TST_RET != 0) {
+		free(xstate);
 		if (TST_ERR == EIO)
 			tst_brk(TCONF, "GETREGSET/SETREGSET is unsupported");
 
@@ -138,6 +151,7 @@  static void do_test(void)
 		tst_res(TINFO,
 			"PTRACE_SETREGSET with reserved bits failed with EINVAL");
 	} else {
+		free(xstate);
 		tst_brk(TBROK | TTERRNO,
 			"PTRACE_SETREGSET failed with unexpected error");
 	}
@@ -152,8 +166,10 @@  static void do_test(void)
 	 * worry about potential stops after this point.
 	 */
 	TEST(ptrace(PTRACE_DETACH, pid, 0, 0));
-	if (TST_RET != 0)
+	if (TST_RET != 0) {
+		free(xstate);
 		tst_brk(TBROK | TTERRNO, "PTRACE_DETACH failed");
+	}
 
 	/* If child 'pid' crashes, only report it as info. */
 	SAFE_WAITPID(pid, &status, 0);
@@ -173,6 +189,7 @@  static void do_test(void)
 	}
 	if (okay)
 		tst_res(TPASS, "wasn't able to set invalid FPU state");
+	free(xstate);
 }
 
 static struct tst_test test = {