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Subject[PATCH] random: Mix cputime from each thread that exits to the pool
Date
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: Nick Kossifidis <mickflemm@gmail.com>
---
kernel/posix-cpu-timers.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 125cb67..f07827a 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -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);

--
1.7.8.6


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