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Commit 61337054 authored by Nick Kossifidis's avatar Nick Kossifidis Committed by Theodore Ts'o
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random: Mix cputime from each thread that exits to the pool 



When a thread exits mix it's cputime (userspace + kernelspace) to the entropy pool.

We don't know how "random" this is, so we use add_device_randomness that doesn't mess
with entropy count.

Signed-off-by: default avatarNick Kossifidis <mickflemm@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent ec8f02da

kernel/posix-cpu-timers.c

+3 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <asm/uaccess.h>

#include <linux/kernel_stat.h>

#include <trace/events/timer.h>

#include <linux/random.h>



/*

 * Called after updating RLIMIT_CPU to run cpu timer and update
@@ -494,6 +495,8 @@ static void cleanup_timers(struct list_head *head, 
 */

void posix_cpu_timers_exit(struct task_struct *tsk)

{

	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,

						sizeof(unsigned long long));

	cleanup_timers(tsk->cpu_timers,

		       tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);