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| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2022-12-02 21:35:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-12-31 15:32:51 +0300 |
| commit | 0bdadab074308dd50cc99b888b4b82d17e0bd071 (patch) | |
| tree | 661ebb8513c63f69c95118e9c5049d6053fddf5a /drivers/pwm | |
| parent | 9a87b1562c3753ef539916d16418d8520bbc860b (diff) | |
| download | linux-0bdadab074308dd50cc99b888b4b82d17e0bd071.tar.xz | |
pwm: sifive: Call pwm_sifive_update_clock() while mutex is held
[ Upstream commit 45558b3abb87eeb2cedb8a59cb2699c120b5102a ]
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 <emil.renner.berthing@canonical.com>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Link: https://lore.kernel.org/r/20221018061656.1428111-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-sifive.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index 2d4fa5e5fdd4..bb7239313401 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; } |