From 9e2fcfc32467bc088d6014ae0337dd8be0680880 Mon Sep 17 00:00:00 2001 From: Sumeet Pawnikar Date: Sun, 7 Dec 2025 20:45:48 +0530 Subject: powercap: fix sscanf() error return value handling [ Upstream commit efc4c35b741af973de90f6826bf35d3b3ac36bf1 ] Fix inconsistent error handling for sscanf() return value check. Implicit boolean conversion is used instead of explicit return value checks. The code checks if (!sscanf(...)) which is incorrect because: 1. sscanf returns the number of successfully parsed items 2. On success, it returns 1 (one item passed) 3. On failure, it returns 0 or EOF 4. The check 'if (!sscanf(...))' is wrong because it treats success (1) as failure All occurrences of sscanf() now uses explicit return value check. With this behavior it returns '-EINVAL' when parsing fails (returns 0 or EOF), and continues when parsing succeeds (returns 1). Signed-off-by: Sumeet Pawnikar [ rjw: Subject and changelog edits ] Link: https://patch.msgid.link/20251207151549.202452-1-sumeet4linux@gmail.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/powercap/powercap_sys.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c index d14b36b75189..1ff369880beb 100644 --- a/drivers/powercap/powercap_sys.c +++ b/drivers/powercap/powercap_sys.c @@ -68,7 +68,7 @@ static ssize_t show_constraint_##_attr(struct device *dev, \ int id; \ struct powercap_zone_constraint *pconst;\ \ - if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \ + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \ return -EINVAL; \ if (id >= power_zone->const_id_cnt) \ return -EINVAL; \ @@ -93,7 +93,7 @@ static ssize_t store_constraint_##_attr(struct device *dev,\ int id; \ struct powercap_zone_constraint *pconst;\ \ - if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \ + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \ return -EINVAL; \ if (id >= power_zone->const_id_cnt) \ return -EINVAL; \ @@ -162,7 +162,7 @@ static ssize_t show_constraint_name(struct device *dev, ssize_t len = -ENODATA; struct powercap_zone_constraint *pconst; - if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) return -EINVAL; if (id >= power_zone->const_id_cnt) return -EINVAL; -- cgit v1.2.3