diff options
| author | Mukesh Ojha <quic_mojha@quicinc.com> | 2024-10-15 00:59:30 +0530 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2024-10-23 11:59:23 +0200 |
| commit | 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e (patch) | |
| tree | e91cd0eb4e689b29365183d82f0654fe60437a3e /drivers/pinctrl/core.c | |
| parent | 56c9d1a033d628b7abac88a5e19c9a5111b01302 (diff) | |
pinmux: Use sequential access to access desc->pinmux data
When two client of the same gpio call pinctrl_select_state() for the
same functionality, we are seeing NULL pointer issue while accessing
desc->mux_owner.
Let's say two processes A, B executing in pin_request() for the same pin
and process A updates the desc->mux_usecount but not yet updated the
desc->mux_owner while process B see the desc->mux_usecount which got
updated by A path and further executes strcmp and while accessing
desc->mux_owner it crashes with NULL pointer.
Serialize the access to mux related setting with a mutex lock.
cpu0 (process A) cpu1(process B)
pinctrl_select_state() { pinctrl_select_state() {
pin_request() { pin_request() {
...
....
} else {
desc->mux_usecount++;
desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
if (desc->mux_usecount > 1)
return 0;
desc->mux_owner = owner;
} }
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Link: https://lore.kernel.org/20241014192930.1539673-1-quic_mojha@quicinc.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/core.c')
| -rw-r--r-- | drivers/pinctrl/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 4061890a1748..b3eec63c00ba 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -220,6 +220,9 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev, /* Set owner */ pindesc->pctldev = pctldev; +#ifdef CONFIG_PINMUX + mutex_init(&pindesc->mux_lock); +#endif /* Copy basic pin info */ if (pin->name) { |