[PATCH][next] gpio: sim: Fix dereference of free'd pointer config

From: Colin King
Date: Tue Apr 27 2021 - 06:24:35 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The error return of config->id dereferences the kfree'd object config.
Fix this by using a temporary variable for the id to avoid this issue.

Addresses-Coverity: ("Read from pointer aftyer free")
Fixes: a49d14276ac4 ("gpio: sim: allocate IDA numbers earlier")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/gpio/gpio-sim.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 2e2e6399e453..7bba5783a043 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -751,8 +751,10 @@ gpio_sim_config_make_item(struct config_group *group, const char *name)

config->id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
if (config->id < 0) {
+ int id = config->id;
+
kfree(config);
- return ERR_PTR(config->id);
+ return ERR_PTR(id);
}

config_item_init_type_name(&config->item, name,
--
2.30.2