Hi Pavan,
On 11/1/2022 12:30 PM, Pavan Kondeti wrote:
Hi Maria,
On Thu, Oct 27, 2022 at 02:54:08PM +0800, Maria Yu wrote:
We've got a dump that current cpu is in pinctrl_commit_state, the
old_state != p->state while the stack is still in the process of
pinmux_disable_setting. So it means even if the current p->state is
changed in new state, the settings are not yet up-to-date enabled
complete yet.
Currently p->state in different value to synchronize the
pinctrl_commit_state behaviors. The p->state will have transaction like
old_state -> NULL -> new_state. When in old_state, it will try to
disable all the all state settings. And when after new state settings
enabled, p->state will changed to the new state after that. So use
smp_mb to synchronize the p->state variable and the settings in order.
---
drivers/pinctrl/core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 9e57f4c62e60..cd917a5b1a0a 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1256,6 +1256,7 @@ static int pinctrl_commit_state(struct pinctrl *p, struct pinctrl_state *state)
}
}
+ smp_mb();
p->state = NULL;
/* Apply all the settings for the new state - pinmux first */
@@ -1305,6 +1306,7 @@ static int pinctrl_commit_state(struct pinctrl *p, struct pinctrl_state *state)
pinctrl_link_add(setting->pctldev, p->dev);
}
+ smp_mb();
p->state = state;
From your commit description, are you inferring that this p->state assignment
re-ordered wrt pinmux_disable_setting()? btw, I don't see any locking that
protects concurrent access to p->state modifications. For whatever reasons, if
a client makes concurrent calls to pinctrl_select_state(), we can land up in
the situation, you are seeing. correct?
correct.
Thanks,
Pavan
--
Thx and BRs,
Aiqun(Maria) Yu
