From: Uwe Kleine-König Date: Fri, 2 Dec 2022 18:35:05 +0000 (+0100) Subject: pwm: sifive: Call pwm_sifive_update_clock() while mutex is held X-Git-Tag: v6.6.7~3840^2~33 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=45558b3abb87eeb2cedb8a59cb2699c120b5102a;p=platform%2Fkernel%2Flinux-starfive.git pwm: sifive: Call pwm_sifive_update_clock() while mutex is held As was documented in commit 0f02f491b786 ("pwm: sifive: Reduce time the controller lock is held") a caller of pwm_sifive_update_clock() must hold the mutex. So fix pwm_sifive_clock_notifier() to grab the lock. While this necessity was only documented later, the race exists since the driver was introduced. Fixes: 9e37a53eb051 ("pwm: sifive: Add a driver for SiFive SoC PWM") Reported-by: Emil Renner Berthing Reviewed-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20221018061656.1428111-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding --- diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index 2d4fa5e..bb72393 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -204,8 +204,11 @@ static int pwm_sifive_clock_notifier(struct notifier_block *nb, struct pwm_sifive_ddata *ddata = container_of(nb, struct pwm_sifive_ddata, notifier); - if (event == POST_RATE_CHANGE) + if (event == POST_RATE_CHANGE) { + mutex_lock(&ddata->lock); pwm_sifive_update_clock(ddata, ndata->new_rate); + mutex_unlock(&ddata->lock); + } return NOTIFY_OK; }