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-rw-r--r--Documentation/filesystems/proc.txt4
-rw-r--r--fs/proc/base.c4
-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/fork.c1
4 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index ef757fc..23cae65 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1323,6 +1323,10 @@ scaled linearly with /proc/<pid>/oom_score_adj.
Writing to /proc/<pid>/oom_score_adj or /proc/<pid>/oom_adj will change the
other with its scaled value.
+The value of /proc/<pid>/oom_score_adj may be reduced no lower than the last
+value set by a CAP_SYS_RESOURCE process. To reduce the value any lower
+requires CAP_SYS_RESOURCE.
+
NOTICE: /proc/<pid>/oom_adj is deprecated and will be removed, please see
Documentation/feature-removal-schedule.txt.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 93f1cdd..9d096e8 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1151,7 +1151,7 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
goto err_task_lock;
}
- if (oom_score_adj < task->signal->oom_score_adj &&
+ if (oom_score_adj < task->signal->oom_score_adj_min &&
!capable(CAP_SYS_RESOURCE)) {
err = -EACCES;
goto err_sighand;
@@ -1164,6 +1164,8 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
atomic_dec(&task->mm->oom_disable_count);
}
task->signal->oom_score_adj = oom_score_adj;
+ if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
+ task->signal->oom_score_adj_min = oom_score_adj;
/*
* Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
* always attainable.
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0740253..f23b5bb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -634,6 +634,8 @@ struct signal_struct {
int oom_adj; /* OOM kill score adjustment (bit shift) */
int oom_score_adj; /* OOM kill score adjustment */
+ int oom_score_adj_min; /* OOM kill score adjustment minimum value.
+ * Only settable by CAP_SYS_RESOURCE. */
struct mutex cred_guard_mutex; /* guard against foreign influences on
* credential calculations
diff --git a/kernel/fork.c b/kernel/fork.c
index 76a1fdd..1499607 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -910,6 +910,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->oom_adj = current->signal->oom_adj;
sig->oom_score_adj = current->signal->oom_score_adj;
+ sig->oom_score_adj_min = current->signal->oom_score_adj_min;
mutex_init(&sig->cred_guard_mutex);