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Commit 491a39dc authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
Browse files

mm/vmpressure.c: fix a signedness bug in vmpressure_register_event() 

commit 518a86713078168acd67cf50bc0b45d54b4cce6c upstream.

The "mode" and "level" variables are enums and in this context GCC will
treat them as unsigned ints so the error handling is never triggered.

I also removed the bogus initializer because it isn't required any more
and it's sort of confusing.

[akpm@linux-foundation.org: reduce implicit and explicit typecasting]
[akpm@linux-foundation.org: fix return value, add comment, per Matthew]
Link: http://lkml.kernel.org/r/20190925110449.GO3264@mwanda


Fixes: 3cadfa2b ("mm/vmpressure.c: convert to use match_string() helper")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Reviewed-by: default avatarMatthew Wilcox <willy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Enrico Weigelt <info@metux.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7bbe6eef

mm/vmpressure.c

+11 −9
Original line number Diff line number Diff line
@@ -358,6 +358,9 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio) 
 * "hierarchy" or "local").

 *

 * To be used as memcg event method.

 *

 * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could

 * not be parsed.

 */

int vmpressure_register_event(struct mem_cgroup *memcg,

			      struct eventfd_ctx *eventfd, const char *args)
@@ -365,7 +368,7 @@ int vmpressure_register_event(struct mem_cgroup *memcg, 
	struct vmpressure *vmpr = memcg_to_vmpressure(memcg);

	struct vmpressure_event *ev;

	enum vmpressure_modes mode = VMPRESSURE_NO_PASSTHROUGH;

	enum vmpressure_levels level = -1;

	enum vmpressure_levels level;

	char *spec, *spec_orig;

	char *token;

	int ret = 0;
@@ -378,20 +381,18 @@ int vmpressure_register_event(struct mem_cgroup *memcg, 


	/* Find required level */

	token = strsep(&spec, ",");

	level = match_string(vmpressure_str_levels, VMPRESSURE_NUM_LEVELS, token);

	if (level < 0) {

		ret = level;

	ret = match_string(vmpressure_str_levels, VMPRESSURE_NUM_LEVELS, token);

	if (ret < 0)

		goto out;

	}

	level = ret;



	/* Find optional mode */

	token = strsep(&spec, ",");

	if (token) {

		mode = match_string(vmpressure_str_modes, VMPRESSURE_NUM_MODES, token);

		if (mode < 0) {

			ret = mode;

		ret = match_string(vmpressure_str_modes, VMPRESSURE_NUM_MODES, token);

		if (ret < 0)

			goto out;

		}

		mode = ret;

	}



	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -407,6 +408,7 @@ int vmpressure_register_event(struct mem_cgroup *memcg, 
	mutex_lock(&vmpr->events_lock);

	list_add(&ev->node, &vmpr->events);

	mutex_unlock(&vmpr->events_lock);

	ret = 0;

out:

	kfree(spec_orig);

	return ret;