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s390: update sampling tag after task pid change 

In a multi-threaded program any thread can call execve(). If this
is not done by the thread group leader, the de_thread() function
replaces the pid of the task that calls execve() with the pid of
thread group leader. If the task reaches user space again without
going over __switch_to() the sampling tag is still set to the old
pid.

Define the arch_setup_new_exec function to verify the task pid
and udpate the tag with LPP if it has changed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
hifive-unleashed-5.1
Martin Schwidefsky 2018-04-20 10:21:21 +02:00
parent 5f3ba878e7
commit 2317b07d05
2 changed files with 13 additions and 0 deletions
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3
arch/s390/include/asm/thread_info.h
View File

@ -45,6 +45,9 @@ struct thread_info {
void arch_release_task_struct(struct task_struct *tsk);
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
void arch_setup_new_exec(void);
#define arch_setup_new_exec arch_setup_new_exec
#endif
/*

10
arch/s390/kernel/process.c
View File

@ -29,6 +29,7 @@
#include <linux/random.h>
#include <linux/export.h>
#include <linux/init_task.h>
#include <asm/cpu_mf.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/vtimer.h>
@ -48,6 +49,15 @@ void flush_thread(void)
{
}
void arch_setup_new_exec(void)
{
if (S390_lowcore.current_pid != current->pid) {
S390_lowcore.current_pid = current->pid;
if (test_facility(40))
lpp(&S390_lowcore.lpp);
}
}
void arch_release_task_struct(struct task_struct *tsk)
{
runtime_instr_release(tsk);