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authorDan Carpenter <dan.carpenter@oracle.com>2019-10-06 17:58:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-10-07 15:47:19 -0700
commit518a86713078168acd67cf50bc0b45d54b4cce6c (patch)
tree7a436f0240bb775bd7a3615224e67e8ed0041002
parent234fdce892f905cbc2674349a9eb4873e288e5b3 (diff)
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mm/vmpressure.c: fix a signedness bug in vmpressure_register_event()
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: 3cadfa2b9497 ("mm/vmpressure.c: convert to use match_string() helper") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Matthew 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmpressure.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index f3b50811497a..4bac22fe1aa2 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -355,6 +355,9 @@ 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)
@@ -362,7 +365,7 @@ 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;
@@ -375,20 +378,18 @@ 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);
@@ -404,6 +405,7 @@ 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;