| From 90ad2bcf76a3369ce02f4e8525d1fa35d524d1aa Mon Sep 17 00:00:00 2001 |
| From: Dan Carpenter <dan.carpenter@oracle.com> |
| Date: Sun, 6 Oct 2019 17:58:28 -0700 |
| Subject: [PATCH] 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: 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| 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; |
| -- |
| 2.7.4 |
| |