4.19-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Torokhov dmitry.torokhov@gmail.com
commit c153a4edff6ab01370fcac8e46f9c89cca1060c2 upstream.
The code in find_pinctrl() takes a mutex and traverses a list of pinctrl structures. Later the caller bumps up reference count on the found structure. Such pattern is not safe as pinctrl that was found may get deleted before the caller gets around to increasing the reference count.
Fix this by taking the reference count in find_pinctrl(), while it still holds the mutex.
Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Link: https://lore.kernel.org/r/ZQs1RgTKg6VJqmPs@google.com Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pinctrl/core.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
--- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -1001,17 +1001,20 @@ static int add_setting(struct pinctrl *p
static struct pinctrl *find_pinctrl(struct device *dev) { - struct pinctrl *p; + struct pinctrl *entry, *p = NULL;
mutex_lock(&pinctrl_list_mutex); - list_for_each_entry(p, &pinctrl_list, node) - if (p->dev == dev) { - mutex_unlock(&pinctrl_list_mutex); - return p; + + list_for_each_entry(entry, &pinctrl_list, node) { + if (entry->dev == dev) { + p = entry; + kref_get(&p->users); + break; } + }
mutex_unlock(&pinctrl_list_mutex); - return NULL; + return p; }
static void pinctrl_free(struct pinctrl *p, bool inlist); @@ -1120,7 +1123,6 @@ struct pinctrl *pinctrl_get(struct devic p = find_pinctrl(dev); if (p) { dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n"); - kref_get(&p->users); return p; }