Commit 8fb4fc68 authored Dec 06, 2006 by Guillem Jover Committed by Linus Torvalds Dec 07, 2006

[PATCH] Allow user processes to raise their oom_adj value



Currently a user process cannot rise its own oom_adj value (i.e.
unprotecting itself from the OOM killer).  As this value is stored in the
task structure it gets inherited and the unprivileged childs will be unable
to rise it.

The EPERM will be handled by the generic proc fs layer, as only processes
with the proper caps or the owner of the process will be able to write to
the file.  So we allow only the processes with CAP_SYS_RESOURCE to lower
the value, otherwise it will get an EACCES which seems more appropriate
than EPERM.

Signed-off-by: Guillem Jover <guillem.jover@nokia.com>
Acked-by: Andrea Arcangeli <andrea@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 3b17979b

fs/proc/base.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -683,8 +683,6 @@ static ssize_t oom_adjust_write(struct file file, const char __user buf,
		char buffer[PROC_NUMBUF], *end;
		int oom_adjust;

		if (!capable(CAP_SYS_RESOURCE))
		return -EPERM;
		memset(buffer, 0, sizeof(buffer));
		if (count > sizeof(buffer) - 1)
		count = sizeof(buffer) - 1;
		@@ -699,6 +697,10 @@ static ssize_t oom_adjust_write(struct file file, const char __user buf,
		task = get_proc_task(file->f_dentry->d_inode);
		if (!task)
		return -ESRCH;
		if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) {
		put_task_struct(task);
		return -EACCES;
		}
		task->oomkilladj = oom_adjust;
		put_task_struct(task);
		if (end - buffer == 0)

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