| Message ID | 20231206090641.18849-1-jensenhuang@friendlyarm.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: rk3x: fix potential spinlock recursion on poll | expand |
Am Mittwoch, 6. Dezember 2023, 10:06:40 CET schrieb Jensen Huang: > Possible deadlock scenario (on reboot): > rk3x_i2c_xfer_common(polling) > -> rk3x_i2c_wait_xfer_poll() > -> rk3x_i2c_irq(0, i2c); > --> spin_lock(&i2c->lock); > ... > <rk3x i2c interrupt> > -> rk3x_i2c_irq(0, i2c); > --> spin_lock(&i2c->lock); (deadlock here) > > Store the IRQ number and disable/enable it around the polling transfer. > This patch has been tested on NanoPC-T4. > > Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com> Reviewed-by: Heiko Stuebner <heiko@sntech.de> > --- > drivers/i2c/busses/i2c-rk3x.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c > index a044ca0c35a1..94514637c3bd 100644 > --- a/drivers/i2c/busses/i2c-rk3x.c > +++ b/drivers/i2c/busses/i2c-rk3x.c > @@ -200,6 +200,7 @@ struct rk3x_i2c { > struct clk *clk; > struct clk *pclk; > struct notifier_block clk_rate_nb; > + int irq; > > /* Settings */ > struct i2c_timings t; > @@ -1087,13 +1088,18 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, > > spin_unlock_irqrestore(&i2c->lock, flags); > > - rk3x_i2c_start(i2c); > - > if (!polling) { > + rk3x_i2c_start(i2c); > + > timeout = wait_event_timeout(i2c->wait, !i2c->busy, > msecs_to_jiffies(WAIT_TIMEOUT)); > } else { > + disable_irq(i2c->irq); > + rk3x_i2c_start(i2c); > + > timeout = rk3x_i2c_wait_xfer_poll(i2c); > + > + enable_irq(i2c->irq); > } > > spin_lock_irqsave(&i2c->lock, flags); > @@ -1310,6 +1316,8 @@ static int rk3x_i2c_probe(struct platform_device *pdev) > return ret; > } > > + i2c->irq = irq; > + > platform_set_drvdata(pdev, i2c); > > if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) { >
Hi Jensen, On Wed, Dec 06, 2023 at 05:06:40PM +0800, Jensen Huang wrote: > Possible deadlock scenario (on reboot): > rk3x_i2c_xfer_common(polling) > -> rk3x_i2c_wait_xfer_poll() > -> rk3x_i2c_irq(0, i2c); > --> spin_lock(&i2c->lock); > ... > <rk3x i2c interrupt> > -> rk3x_i2c_irq(0, i2c); > --> spin_lock(&i2c->lock); (deadlock here) > > Store the IRQ number and disable/enable it around the polling transfer. > This patch has been tested on NanoPC-T4. > > Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com> Looks good, Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Thanks, Andi
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index a044ca0c35a1..94514637c3bd 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -200,6 +200,7 @@ struct rk3x_i2c { struct clk *clk; struct clk *pclk; struct notifier_block clk_rate_nb; + int irq; /* Settings */ struct i2c_timings t; @@ -1087,13 +1088,18 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, spin_unlock_irqrestore(&i2c->lock, flags); - rk3x_i2c_start(i2c); - if (!polling) { + rk3x_i2c_start(i2c); + timeout = wait_event_timeout(i2c->wait, !i2c->busy, msecs_to_jiffies(WAIT_TIMEOUT)); } else { + disable_irq(i2c->irq); + rk3x_i2c_start(i2c); + timeout = rk3x_i2c_wait_xfer_poll(i2c); + + enable_irq(i2c->irq); } spin_lock_irqsave(&i2c->lock, flags); @@ -1310,6 +1316,8 @@ static int rk3x_i2c_probe(struct platform_device *pdev) return ret; } + i2c->irq = irq; + platform_set_drvdata(pdev, i2c); if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {
Possible deadlock scenario (on reboot): rk3x_i2c_xfer_common(polling) -> rk3x_i2c_wait_xfer_poll() -> rk3x_i2c_irq(0, i2c); --> spin_lock(&i2c->lock); ... <rk3x i2c interrupt> -> rk3x_i2c_irq(0, i2c); --> spin_lock(&i2c->lock); (deadlock here) Store the IRQ number and disable/enable it around the polling transfer. This patch has been tested on NanoPC-T4. Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com> --- drivers/i2c/busses/i2c-rk3x.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)