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SubjectRe: [PATCH 17/23] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32
On 2016/6/9 1:00, Yury Norov wrote:
> On Wed, Jun 08, 2016 at 09:34:09AM +0800, zhouchengming wrote:
>> On 2016/5/24 8:04, Yury Norov wrote:
>>> Here new aarch32 ptrace syscall handler is introsuced to avoid run-time
>>> detection of the task type.
>>>
>>> Signed-off-by: Yury Norov<ynorov@caviumnetworks.com>
>
> [...]
>
>> Hello, I found ilp32 will use sys_ptrace, not compat_sys_ptrace. So I write
>> a little patch to see if can solve the problem correctly.
>>
>> Thanks.
>>
>> From f6156236df578bb05c4a17e7f9776ceaf8f7afe6 Mon Sep 17 00:00:00 2001
>> From: Zhou Chengming<zhouchengming1@huawei.com>
>> Date: Wed, 8 Jun 2016 09:46:23 +0800
>> Subject: [PATCH] ilp32: use compat_sys_ptrace instead of sys_ptrace
>>
>> When we analyze a testcase of ptrace that failed on ilp32, we found
>> the syscall that the ilp32 uses is sys_ptrace, not compat_sys_ptrace.
>> Because in include/uapi/asm-generic/unistd.h it's defined like:
>> __SYSCALL(__NR_ptrace, sys_ptrace)
>> So we change it to __SC_COMP(__NR_ptrace, sys_ptrace, compat_sys_ptrace),
>> let compat tasks use the compat_sys_ptrace.
>>
>> Signed-off-by: Zhou Chengming<zhouchengming1@huawei.com>
>> ---
>> include/uapi/asm-generic/unistd.h | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/uapi/asm-generic/unistd.h
>> b/include/uapi/asm-generic/unistd.h
>> index 2862d2e..50ee770 100644
>> --- a/include/uapi/asm-generic/unistd.h
>> +++ b/include/uapi/asm-generic/unistd.h
>> @@ -364,7 +364,7 @@ __SC_WRAP(__NR_syslog, sys_syslog)
>>
>> /* kernel/ptrace.c */
>> #define __NR_ptrace 117
>> -__SYSCALL(__NR_ptrace, sys_ptrace)
>> +__SC_COMP(__NR_ptrace, sys_ptrace, compat_sys_ptrace)
>>
>> /* kernel/sched/core.c */
>> #define __NR_sched_setparam 118
>> --
>> 1.7.7
>>
>
> Hi Zhou,
>
> Thank you for the catch.
>
> Could you also show the test that is failed for you. It should
> probably be sent to LTP maillist.
>
> I'm not sure your fix correct as it affects other architectures that
> use standard unistd.h. I think it's better to redirect the syscall in
> arch/arm64/kernel/sys_ilp32.c with corresponding definition.
>
> Yury
>
> .
>

Sorry, I missed this mail. Thanks for your reply. :)
I attach the testcase file of ptrace that failed on ilp32.
I also think it's better to redirect the syscall in ilp32, so I changed
the patch.


From 7e692ba1adf02c2a2f125836f5222f455c9ffe56 Mon Sep 17 00:00:00 2001
From: Zhou Chengming <zhouchengming1@huawei.com>
Date: Sat, 25 Jun 2016 18:02:51 +0800
Subject: [PATCH] ilp32 should use compat_sys_ptrace

The file include/uapi/asm-generic/unistd.h defines this:
__SYSCALL(__NR_ptrace, sys_ptrace)
It may cause some ptrace tests failed on ilp32. So we redirect the ptrace
syscall in arch/arm64/kernel/sys_ilp32.c with corresponding definition.

Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
---
arch/arm64/kernel/sys_ilp32.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c
index d85fe94..06d5e1b 100644
--- a/arch/arm64/kernel/sys_ilp32.c
+++ b/arch/arm64/kernel/sys_ilp32.c
@@ -46,6 +46,9 @@
asmlinkage long ilp32_sys_rt_sigreturn_wrapper(void);
#define compat_sys_rt_sigreturn ilp32_sys_rt_sigreturn_wrapper

+/* ilp32 should use compat_sys_ptrace */
+#define sys_ptrace compat_sys_ptrace
+
#include <asm/syscall.h>

#undef __SYSCALL
--
1.7.7


#include <stdio.h>
#include <stdlib.h>
#include <sys/ptrace.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <signal.h>

int main()
{
pid_t child;
unsigned long exit_status;
int status;
int is_get_event = 0;
long ptrace_ret;

int result = SIGTRAP | (PTRACE_EVENT_EXIT<<8);

child = fork();
if(child < 0)
{
printf("fork error\n");
exit(1);
}
else if(child == 0)
{
sleep(1);
exit(127);
}
else
{
ptrace_ret = ptrace(PTRACE_ATTACH, child, NULL, NULL);
if(ptrace_ret != 0)
{
printf("ptrace PTRACE_ATTACH error %d \n", errno);
exit(1);
}

printf("ATTACH SUCCESS\n");
sleep(1);

ptrace_ret = ptrace(PTRACE_SETOPTIONS, child, NULL, PTRACE_O_TRACEEXIT);
if(ptrace_ret != 0)
{
printf("ptrace PTRACE_SETOPTIONS PTRACE_O_TRACEFORK error %d \n", errno);
ptrace(PTRACE_DETACH, child, NULL, NULL);
exit(1);
}

printf("SETOPTIONS SUCCESS!\n");

while(1)
{
usleep(1);
pid_t pid;
if ((pid = wait(&status)) == -1) {
perror("wait");
exit(1);
};

printf("pid : %d\n", pid);
printf("the child process stops. status: %d, signal? %d, exit? %d, continue? %d, stop? %d\n" , WEXITSTATUS(status) , WIFSIGNALED(status) , WIFEXITED(status) , WIFCONTINUED(status) ,WIFSTOPPED(status));

if (WSTOPSIG(status) == SIGTRAP)
{
printf("status : %d\n", status>>8);
if (status>>8 == result)
{
if (ptrace(PTRACE_GETEVENTMSG, child, NULL, &exit_status))
{
perror("error geteventmsg");
exit(1);
}

printf("exit_status %d\n", WEXITSTATUS((int)exit_status));

exit_status = WEXITSTATUS(exit_status);

if (exit_status != 127)
{
printf("exit status is not equal with 127!\n");
exit(1);
}
is_get_event = 1;
}
}

if (WIFEXITED(status))
{
printf("child exit!\n");
break;
}

if(ptrace(PTRACE_CONT, pid, NULL, (void *) SIGCONT))
{
printf("ptrace cont %d error %d\n", pid, errno);
exit(1);
}

}

if (is_get_event)
exit(0);
else
exit(1);
}
}
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