| Message ID | 20250213112416.1610678-1-mordan@ispras.ru (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tty: owl-uart: fix call balance of owl_port->clk handling routines | expand |
On Thu, Feb 13, 2025 at 02:24:16PM +0300, Vitalii Mordan wrote: > If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in > all error paths to ensure proper cleanup. However, if uart_add_one_port() > returns an error in owl_uart_probe(), the owl_port->clk clock will not be > disabled. > > Use the devm_clk_get_enabled() helper function to ensure proper call > balance for owl_port->clk. > Do not use newly introduced APIs to fix old bugs. The bug should be fixed separately to allow backporting and the conversion should be done on top. - Mani > Found by Linux Verification Center (linuxtesting.org) with Klever. > > Fixes: abf42d2f333b ("tty: serial: owl: add "much needed" clk_prepare_enable()") > Cc: stable@vger.kernel.org > Signed-off-by: Vitalii Mordan <mordan@ispras.ru> > --- > drivers/tty/serial/owl-uart.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c > index 0542882cfbbe..64446820437c 100644 > --- a/drivers/tty/serial/owl-uart.c > +++ b/drivers/tty/serial/owl-uart.c > @@ -680,18 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev) > if (!owl_port) > return -ENOMEM; > > - owl_port->clk = devm_clk_get(&pdev->dev, NULL); > + owl_port->clk = devm_clk_get_enabled(&pdev->dev, NULL); > if (IS_ERR(owl_port->clk)) { > - dev_err(&pdev->dev, "could not get clk\n"); > + dev_err(&pdev->dev, "could not get and enable clk\n"); > return PTR_ERR(owl_port->clk); > } > > - ret = clk_prepare_enable(owl_port->clk); > - if (ret) { > - dev_err(&pdev->dev, "could not enable clk\n"); > - return ret; > - } > - > owl_port->port.dev = &pdev->dev; > owl_port->port.line = pdev->id; > owl_port->port.type = PORT_OWL; > @@ -701,7 +695,6 @@ static int owl_uart_probe(struct platform_device *pdev) > owl_port->port.uartclk = clk_get_rate(owl_port->clk); > if (owl_port->port.uartclk == 0) { > dev_err(&pdev->dev, "clock rate is zero\n"); > - clk_disable_unprepare(owl_port->clk); > return -EINVAL; > } > owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY; > @@ -725,7 +718,6 @@ static void owl_uart_remove(struct platform_device *pdev) > > uart_remove_one_port(&owl_uart_driver, &owl_port->port); > owl_uart_ports[pdev->id] = NULL; > - clk_disable_unprepare(owl_port->clk); > } > > static struct platform_driver owl_uart_platform_driver = { > -- > 2.25.1 >
On Fri, 14. Feb 22:44, Manivannan Sadhasivam wrote: > On Thu, Feb 13, 2025 at 02:24:16PM +0300, Vitalii Mordan wrote: > > If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in > > all error paths to ensure proper cleanup. However, if uart_add_one_port() > > returns an error in owl_uart_probe(), the owl_port->clk clock will not be > > disabled. > > > > Use the devm_clk_get_enabled() helper function to ensure proper call > > balance for owl_port->clk. > > > > Do not use newly introduced APIs to fix old bugs. The bug should be fixed > separately to allow backporting and the conversion should be done on top. These relatively new helpers are already available in all currently supported stable kernels including 5.4.y. Commit 7ef9651e9792 ("clk: Provide new devm_clk helpers for prepared and enabled clocks") was conveniently backported there as a dependency for the similar bug fixes.
On Fri, Feb 14, 2025 at 09:39:09PM +0300, Fedor Pchelkin wrote: > On Fri, 14. Feb 22:44, Manivannan Sadhasivam wrote: > > On Thu, Feb 13, 2025 at 02:24:16PM +0300, Vitalii Mordan wrote: > > > If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in > > > all error paths to ensure proper cleanup. However, if uart_add_one_port() > > > returns an error in owl_uart_probe(), the owl_port->clk clock will not be > > > disabled. > > > > > > Use the devm_clk_get_enabled() helper function to ensure proper call > > > balance for owl_port->clk. > > > > > > > Do not use newly introduced APIs to fix old bugs. The bug should be fixed > > separately to allow backporting and the conversion should be done on top. > > These relatively new helpers are already available in all currently > supported stable kernels including 5.4.y. > > Commit 7ef9651e9792 ("clk: Provide new devm_clk helpers for prepared and > enabled clocks") was conveniently backported there as a dependency for > the similar bug fixes. Ah, then fine with me. - Mani
On Thu, Feb 13, 2025 at 02:24:16PM +0300, Vitalii Mordan wrote: > If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in > all error paths to ensure proper cleanup. However, if uart_add_one_port() > returns an error in owl_uart_probe(), the owl_port->clk clock will not be > disabled. > > Use the devm_clk_get_enabled() helper function to ensure proper call > balance for owl_port->clk. > > Found by Linux Verification Center (linuxtesting.org) with Klever. > > Fixes: abf42d2f333b ("tty: serial: owl: add "much needed" clk_prepare_enable()") > Cc: stable@vger.kernel.org > Signed-off-by: Vitalii Mordan <mordan@ispras.ru> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > drivers/tty/serial/owl-uart.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c > index 0542882cfbbe..64446820437c 100644 > --- a/drivers/tty/serial/owl-uart.c > +++ b/drivers/tty/serial/owl-uart.c > @@ -680,18 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev) > if (!owl_port) > return -ENOMEM; > > - owl_port->clk = devm_clk_get(&pdev->dev, NULL); > + owl_port->clk = devm_clk_get_enabled(&pdev->dev, NULL); > if (IS_ERR(owl_port->clk)) { > - dev_err(&pdev->dev, "could not get clk\n"); > + dev_err(&pdev->dev, "could not get and enable clk\n"); > return PTR_ERR(owl_port->clk); > } > > - ret = clk_prepare_enable(owl_port->clk); > - if (ret) { > - dev_err(&pdev->dev, "could not enable clk\n"); > - return ret; > - } > - > owl_port->port.dev = &pdev->dev; > owl_port->port.line = pdev->id; > owl_port->port.type = PORT_OWL; > @@ -701,7 +695,6 @@ static int owl_uart_probe(struct platform_device *pdev) > owl_port->port.uartclk = clk_get_rate(owl_port->clk); > if (owl_port->port.uartclk == 0) { > dev_err(&pdev->dev, "clock rate is zero\n"); > - clk_disable_unprepare(owl_port->clk); > return -EINVAL; > } > owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY; > @@ -725,7 +718,6 @@ static void owl_uart_remove(struct platform_device *pdev) > > uart_remove_one_port(&owl_uart_driver, &owl_port->port); > owl_uart_ports[pdev->id] = NULL; > - clk_disable_unprepare(owl_port->clk); > } > > static struct platform_driver owl_uart_platform_driver = { > -- > 2.25.1 >
diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c index 0542882cfbbe..64446820437c 100644 --- a/drivers/tty/serial/owl-uart.c +++ b/drivers/tty/serial/owl-uart.c @@ -680,18 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev) if (!owl_port) return -ENOMEM; - owl_port->clk = devm_clk_get(&pdev->dev, NULL); + owl_port->clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(owl_port->clk)) { - dev_err(&pdev->dev, "could not get clk\n"); + dev_err(&pdev->dev, "could not get and enable clk\n"); return PTR_ERR(owl_port->clk); } - ret = clk_prepare_enable(owl_port->clk); - if (ret) { - dev_err(&pdev->dev, "could not enable clk\n"); - return ret; - } - owl_port->port.dev = &pdev->dev; owl_port->port.line = pdev->id; owl_port->port.type = PORT_OWL; @@ -701,7 +695,6 @@ static int owl_uart_probe(struct platform_device *pdev) owl_port->port.uartclk = clk_get_rate(owl_port->clk); if (owl_port->port.uartclk == 0) { dev_err(&pdev->dev, "clock rate is zero\n"); - clk_disable_unprepare(owl_port->clk); return -EINVAL; } owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY; @@ -725,7 +718,6 @@ static void owl_uart_remove(struct platform_device *pdev) uart_remove_one_port(&owl_uart_driver, &owl_port->port); owl_uart_ports[pdev->id] = NULL; - clk_disable_unprepare(owl_port->clk); } static struct platform_driver owl_uart_platform_driver = {
If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in all error paths to ensure proper cleanup. However, if uart_add_one_port() returns an error in owl_uart_probe(), the owl_port->clk clock will not be disabled. Use the devm_clk_get_enabled() helper function to ensure proper call balance for owl_port->clk. Found by Linux Verification Center (linuxtesting.org) with Klever. Fixes: abf42d2f333b ("tty: serial: owl: add "much needed" clk_prepare_enable()") Cc: stable@vger.kernel.org Signed-off-by: Vitalii Mordan <mordan@ispras.ru> --- drivers/tty/serial/owl-uart.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-)