s390: update sampling tag after task pid change
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Fri, 20 Apr 2018 08:21:21 +0000 (10:21 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 23 Apr 2018 05:57:17 +0000 (07:57 +0200)
commit2317b07d05d2b136eb4dc9609807c9111bda3b2a
treeb4290d962400d850031b1890568ef00a7f3fe9ab
parent5f3ba878e7a2ffef82fb0882c0dd2c3507d734bc
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>
arch/s390/include/asm/thread_info.h
arch/s390/kernel/process.c