Messages in this thread | | | Date | Wed, 22 Jan 2020 15:56:05 -0800 (PST) | From | Palmer Dabbelt <> | Subject | Re: [PATCH] macb: Don't unregister clks unconditionally |
| |
On Fri, 03 Jan 2020 16:19:21 PST (-0800), sboyd@kernel.org wrote: > The only clk init function in this driver that register a clk is > fu540_c000_clk_init(), and thus we need to unregister the clk when this > driver is removed on that platform. Other init functions, for example > macb_clk_init(), don't register clks and therefore we shouldn't > unregister the clks when this driver is removed. Convert this > registration path to devm so it gets auto-unregistered when this driver > is removed and drop the clk_unregister() calls in driver remove (and > error paths) so that we don't erroneously remove a clk from the system > that isn't registered by this driver. > > Otherwise we get strange crashes with a use-after-free when the > devm_clk_get() call in macb_clk_init() calls clk_put() on a clk pointer > that has become invalid because it is freed in clk_unregister(). > > Cc: Nicolas Ferre <nicolas.ferre@microchip.com> > Cc: Yash Shah <yash.shah@sifive.com> > Reported-by: Guenter Roeck <linux@roeck-us.net> > Fixes: c218ad559020 ("macb: Add support for SiFive FU540-C000") > Signed-off-by: Stephen Boyd <sboyd@kernel.org> > --- > drivers/net/ethernet/cadence/macb_main.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c > index 9c767ee252ac..7dce403fd27c 100644 > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -4069,7 +4069,7 @@ static int fu540_c000_clk_init(struct platform_device *pdev, struct clk **pclk, > mgmt->rate = 0; > mgmt->hw.init = &init; > > - *tx_clk = clk_register(NULL, &mgmt->hw); > + *tx_clk = devm_clk_register(&pdev->dev, &mgmt->hw); > if (IS_ERR(*tx_clk)) > return PTR_ERR(*tx_clk); > > @@ -4397,7 +4397,6 @@ static int macb_probe(struct platform_device *pdev) > > err_disable_clocks: > clk_disable_unprepare(tx_clk); > - clk_unregister(tx_clk); > clk_disable_unprepare(hclk); > clk_disable_unprepare(pclk); > clk_disable_unprepare(rx_clk); > @@ -4427,7 +4426,6 @@ static int macb_remove(struct platform_device *pdev) > pm_runtime_dont_use_autosuspend(&pdev->dev); > if (!pm_runtime_suspended(&pdev->dev)) { > clk_disable_unprepare(bp->tx_clk); > - clk_unregister(bp->tx_clk); > clk_disable_unprepare(bp->hclk); > clk_disable_unprepare(bp->pclk); > clk_disable_unprepare(bp->rx_clk);
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Thanks!
| |