Since PAGE_ALIGN is aligning up(the next page boundary), this can
prevent input values wrapped to 0 and cause strange result to user.
This patch also rename the second arg of
res_counter_memparse_write_strategy() to 'resp' and add a local
variable 'res' to save the too often dereferences. Thanks Andrew
for pointing it out!
Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx>
Reported-by: Li Wenpeng <xingke.lwp@xxxxxxxxxx>
---
kernel/res_counter.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 3f0417f..be8ddda 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -178,23 +178,29 @@ u64 res_counter_read_u64(struct res_counter *counter, int member)
#endif
int res_counter_memparse_write_strategy(const char *buf,
- unsigned long long *res)
+ unsigned long long *resp)
{
char *end;
+ unsigned long long res;
/* return RES_COUNTER_MAX(unlimited) if "-1" is specified */
if (*buf == '-') {
- *res = simple_strtoull(buf + 1, &end, 10);
- if (*res != 1 || *end != '\0')
+ res = simple_strtoull(buf + 1, &end, 10);
+ if (res != 1 || *end != '\0')
return -EINVAL;
- *res = RES_COUNTER_MAX;
+ *resp = RES_COUNTER_MAX;
return 0;
}
- *res = memparse(buf, &end);
+ res = memparse(buf, &end);
if (*end != '\0')
return -EINVAL;
- *res = PAGE_ALIGN(*res);
+ if (PAGE_ALIGN(res) >= res)
+ res = PAGE_ALIGN(res);
+ else
+ res = RES_COUNTER_MAX; /* avoid PAGE_ALIGN wrapping to zero */
+
+ *resp = res;
return 0;
}
--
1.7.9.5
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>