| Message ID | 1463481333-23438-2-git-send-email-boris.brezillon@free-electrons.com |
|---|---|
| State | New |
| Headers | show |
On Tue, May 17, 2016 at 12:35:33PM +0200, Boris Brezillon wrote: [...] > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > index 427142d..3d2eeaa 100644 > --- a/drivers/pwm/core.c > +++ b/drivers/pwm/core.c > @@ -143,10 +143,6 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > if (args->args[0] >= pc->npwm) > return ERR_PTR(-EINVAL); > > - pwm = pwm_request_from_chip(pc, args->args[0], NULL); > - if (IS_ERR(pwm)) > - return pwm; > - > pwm->args.period = args->args[1]; > > if (args->args[2] & PWM_POLARITY_INVERTED) > @@ -154,6 +150,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > else > pwm->args.polarity = PWM_POLARITY_NORMAL; > > + pwm = pwm_request_from_chip(pc, args->args[0], NULL); > + if (IS_ERR(pwm)) > + return pwm; > + Can't do that, because now you're dereferencing an uninitialized pointer. > return pwm; > } > EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); > @@ -169,12 +169,12 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) > if (args->args[0] >= pc->npwm) > return ERR_PTR(-EINVAL); > > + pwm->args.period = args->args[1]; Same here. > diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c > index 58b709f..c33bd42 100644 > --- a/drivers/pwm/pwm-pxa.c > +++ b/drivers/pwm/pwm-pxa.c > @@ -156,12 +156,12 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) > { > struct pwm_device *pwm; > > + pwm->args.period = args->args[0]; And here. Thierry
On Tue, 17 May 2016 13:04:38 +0200 Thierry Reding <thierry.reding@gmail.com> wrote: > On Tue, May 17, 2016 at 12:35:33PM +0200, Boris Brezillon wrote: > [...] > > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > > index 427142d..3d2eeaa 100644 > > --- a/drivers/pwm/core.c > > +++ b/drivers/pwm/core.c > > @@ -143,10 +143,6 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > > if (args->args[0] >= pc->npwm) > > return ERR_PTR(-EINVAL); > > > > - pwm = pwm_request_from_chip(pc, args->args[0], NULL); > > - if (IS_ERR(pwm)) > > - return pwm; > > - > > pwm->args.period = args->args[1]; > > > > if (args->args[2] & PWM_POLARITY_INVERTED) > > @@ -154,6 +150,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > > else > > pwm->args.polarity = PWM_POLARITY_NORMAL; > > > > + pwm = pwm_request_from_chip(pc, args->args[0], NULL); > > + if (IS_ERR(pwm)) > > + return pwm; > > + > > Can't do that, because now you're dereferencing an uninitialized > pointer. Yes, forget this patch, it's not needed anyway since all PWM users are now directly calling pwm_apply_args() after requesting the PWM. The bad news is I broke bisectibilty :-(. Still does not explain the bug reported by Mika.
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 427142d..3d2eeaa 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -143,10 +143,6 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) if (args->args[0] >= pc->npwm) return ERR_PTR(-EINVAL); - pwm = pwm_request_from_chip(pc, args->args[0], NULL); - if (IS_ERR(pwm)) - return pwm; - pwm->args.period = args->args[1]; if (args->args[2] & PWM_POLARITY_INVERTED) @@ -154,6 +150,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) else pwm->args.polarity = PWM_POLARITY_NORMAL; + pwm = pwm_request_from_chip(pc, args->args[0], NULL); + if (IS_ERR(pwm)) + return pwm; + return pwm; } EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); @@ -169,12 +169,12 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) if (args->args[0] >= pc->npwm) return ERR_PTR(-EINVAL); + pwm->args.period = args->args[1]; + pwm = pwm_request_from_chip(pc, args->args[0], NULL); if (IS_ERR(pwm)) return pwm; - pwm->args.period = args->args[1]; - return pwm; } diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c index 58b709f..c33bd42 100644 --- a/drivers/pwm/pwm-pxa.c +++ b/drivers/pwm/pwm-pxa.c @@ -156,12 +156,12 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) { struct pwm_device *pwm; + pwm->args.period = args->args[0]; + pwm = pwm_request_from_chip(pc, 0, NULL); if (IS_ERR(pwm)) return pwm; - pwm->args.period = args->args[0]; - return pwm; }
Commit e39c0df1be5a ("pwm: Introduce the pwm_args concept"), moved the period and polarity initialization steps into pwm_request_device() (called by pwm_request_from_chip()) based on the pwm->args information. Make sure we fill pwm->args fields before calling pwm_request_from_chip(). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Reported-by: Mika Penttilä <mika.penttila@nextfour.com> Fixes: e39c0df1be5a ("pwm: Introduce the pwm_args concept") --- Mika, Can you test after applying this patch and let me know if it fixes your bug. Thanks, Boris drivers/pwm/core.c | 12 ++++++------ drivers/pwm/pwm-pxa.c | 4 ++-- 2 files changed, 8 insertions(+), 8 deletions(-)