| Message ID | 20250214154632.1907425-1-mordan@ispras.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling routines | expand |
On Fri, Feb 14, 2025 at 06:46:32PM +0300, Vitalii Mordan wrote: > If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not > be disabled in any path. > > The return value of clk_prepare_enable() is not checked. If mhdp->clk was > not enabled, it may be disabled in the error path of cdns_mhdp_probe() > (e.g., if cdns_mhdp_load_firmware() fails) or in cdns_mhdp_remove() after > a successful cdns_mhdp_probe() call. > > Use the devm_clk_get_enabled() helper function to ensure proper call > balance for mhdp->clk. > > Found by Linux Verification Center (linuxtesting.org) with Klever. > > Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge") > Signed-off-by: Vitalii Mordan <mordan@ispras.ru> > --- > v2: Use devm_clk_get_enabled() helper function, as per Dmitry Baryshkov's > request. > v3: Describe the paths that lead to unbalanced clock handling routines, > as requested by Dmitry Baryshkov > > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
On Fri, 14 Feb 2025 18:46:32 +0300, Vitalii Mordan wrote: > If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not > be disabled in any path. > > The return value of clk_prepare_enable() is not checked. If mhdp->clk was > not enabled, it may be disabled in the error path of cdns_mhdp_probe() > (e.g., if cdns_mhdp_load_firmware() fails) or in cdns_mhdp_remove() after > a successful cdns_mhdp_probe() call. > > [...] Applied, thanks! [1/1] gpu: cdns-mhdp8546: fix call balance of mhdp->clk handling routines https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/f65727be3fa5 Rob
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c index d081850e3c03..d4e4f484cbe5 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c @@ -2463,9 +2463,9 @@ static int cdns_mhdp_probe(struct platform_device *pdev) if (!mhdp) return -ENOMEM; - clk = devm_clk_get(dev, NULL); + clk = devm_clk_get_enabled(dev, NULL); if (IS_ERR(clk)) { - dev_err(dev, "couldn't get clk: %ld\n", PTR_ERR(clk)); + dev_err(dev, "couldn't get and enable clk: %ld\n", PTR_ERR(clk)); return PTR_ERR(clk); } @@ -2504,14 +2504,12 @@ static int cdns_mhdp_probe(struct platform_device *pdev) mhdp->info = of_device_get_match_data(dev); - clk_prepare_enable(clk); - pm_runtime_enable(dev); ret = pm_runtime_resume_and_get(dev); if (ret < 0) { dev_err(dev, "pm_runtime_resume_and_get failed\n"); pm_runtime_disable(dev); - goto clk_disable; + return ret; } if (mhdp->info && mhdp->info->ops && mhdp->info->ops->init) { @@ -2590,8 +2588,6 @@ static int cdns_mhdp_probe(struct platform_device *pdev) runtime_put: pm_runtime_put_sync(dev); pm_runtime_disable(dev); -clk_disable: - clk_disable_unprepare(mhdp->clk); return ret; } @@ -2632,8 +2628,6 @@ static void cdns_mhdp_remove(struct platform_device *pdev) cancel_work_sync(&mhdp->modeset_retry_work); flush_work(&mhdp->hpd_work); /* Ignoring mhdp->hdcp.check_work and mhdp->hdcp.prop_work here. */ - - clk_disable_unprepare(mhdp->clk); } static const struct of_device_id mhdp_ids[] = {
If the clock mhdp->clk was not enabled in cdns_mhdp_probe(), it should not be disabled in any path. The return value of clk_prepare_enable() is not checked. If mhdp->clk was not enabled, it may be disabled in the error path of cdns_mhdp_probe() (e.g., if cdns_mhdp_load_firmware() fails) or in cdns_mhdp_remove() after a successful cdns_mhdp_probe() call. Use the devm_clk_get_enabled() helper function to ensure proper call balance for mhdp->clk. Found by Linux Verification Center (linuxtesting.org) with Klever. Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge") Signed-off-by: Vitalii Mordan <mordan@ispras.ru> --- v2: Use devm_clk_get_enabled() helper function, as per Dmitry Baryshkov's request. v3: Describe the paths that lead to unbalanced clock handling routines, as requested by Dmitry Baryshkov drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)