diff options
| author | Sumeet Pawnikar <sumeet4linux@gmail.com> | 2025-12-07 20:45:48 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-17 16:31:28 +0100 |
| commit | feb28b6827ece47cce585599a00b02ee579532bc (patch) | |
| tree | a3d9831dd2af6f296477f379ab3dc820bc155e31 | |
| parent | 3835d59f6999338220ceaf41cfa60967c90b84a8 (diff) | |
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 <sumeet4linux@gmail.com>
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20251207151549.202452-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/powercap/powercap_sys.c | 6 |
1 files 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; |