| Message ID | 20230303213716.2123717-1-u.kleine-koenig@pengutronix.de |
|---|---|
| Headers | show |
| Series | watchdog: Convert to platform remove callback returning void | expand |
Hi Uwe, On 3/3/23 13:36, Uwe Kleine-König wrote: > Returning early in a platform driver's remove callback is wrong. In this > case the watchdog device is never removed although it's parent is gone > which likely can trigger a use-after-free in sysfs. Also the two used > clocks will never be disabled. > > Instead only warn if s3c2410wdt_enable() fails and cleanup. Note that > returning 0 is the right thing to do then to suppress another warning > message by the driver core. > > Fixes: 4f1f653a68d6 ("watchdog: s3c2410_wdt: use syscon regmap interface to configure pmu register") > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/watchdog/s3c2410_wdt.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c > index 200ba236a72e..cf104a844a43 100644 > --- a/drivers/watchdog/s3c2410_wdt.c > +++ b/drivers/watchdog/s3c2410_wdt.c > @@ -782,7 +782,8 @@ static int s3c2410wdt_remove(struct platform_device *dev) > > ret = s3c2410wdt_enable(wdt, false); > if (ret < 0) > - return ret; > + dev_warn(&dev->dev, > + "Failed to disable watchdog (%pe)\n", ERR_PTR(ret)); > > watchdog_unregister_device(&wdt->wdt_device); > I sent out two patches a minute ago which should make this patch as well as the use of the remove_new callback unnecessary. Guenter
> Hello, > > this patch series adapts the platform drivers below drivers/watchdog to > use the .remove_new() callback. Compared to the traditional .remove() > callback .remove_new() returns no value. This is a good thing because > the driver core doesn't (and cannot) cope for errors during remove. The > only effect of a non-zero return value in .remove() is that the driver > core emits a warning. The device is removed anyhow and an early return > from .remove() usually yields a resource leak. One driver suffering from > this problem (s3c2410) is fixed by the first patch. This patch set applied on top of Linux next. Build tested with gcc-12, clang-16 and clang nightly. Boot and LTP smoketests performed on - qemu-x86_64 - qemu-arm64 - fvp-aemva - qemu-armv7 - qemu-i386 Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> -- Linaro LKFT https://lkft.linaro.org
Hello, this patch series adapts the platform drivers below drivers/watchdog to use the .remove_new() callback. Compared to the traditional .remove() callback .remove_new() returns no value. This is a good thing because the driver core doesn't (and cannot) cope for errors during remove. The only effect of a non-zero return value in .remove() is that the driver core emits a warning. The device is removed anyhow and an early return from .remove() usually yields a resource leak. One driver suffering from this problem (s3c2410) is fixed by the first patch. By changing the remove callback to return void driver authors cannot reasonably (but wrongly) assume any more that there happens some kind of cleanup later. All watchdog drivers but the above mentioned one returned zero unconditionally in their remove callback, so they could all be converted trivially to .remove_new(). Note that this series depends on commit 5c5a7680e67b ("platform: Provide a remove callback that returns no value") that is already in Linus' tree but not yet included in a tagged version. Best regards Uwe Uwe Kleine-König (34): watchdog: s3c2410: Don't skip cleanup in remove's error path watchdog: acquirewdt: Convert to platform remove callback returning void watchdog: advantechwdt: Convert to platform remove callback returning void watchdog: ar7: Convert to platform remove callback returning void watchdog: at91rm9200: Convert to platform remove callback returning void watchdog: ath79: Convert to platform remove callback returning void watchdog: bcm2835: Convert to platform remove callback returning void watchdog: bcm47xx: Convert to platform remove callback returning void watchdog: bcm_kona: Convert to platform remove callback returning void watchdog: cpwd: Convert to platform remove callback returning void watchdog: dw: Convert to platform remove callback returning void watchdog: gef: Convert to platform remove callback returning void watchdog: geodewdt: Convert to platform remove callback returning void watchdog: ib700wdt: Convert to platform remove callback returning void watchdog: ie6xx: Convert to platform remove callback returning void watchdog: lpc18xx: Convert to platform remove callback returning void watchdog: mtx-1: Convert to platform remove callback returning void watchdog: nic7018: Convert to platform remove callback returning void watchdog: nv_tco: Convert to platform remove callback returning void watchdog: omap: Convert to platform remove callback returning void watchdog: orion: Convert to platform remove callback returning void watchdog: rc32434: Convert to platform remove callback returning void watchdog: rdc321x: Convert to platform remove callback returning void watchdog: renesas: Convert to platform remove callback returning void watchdog: riowd: Convert to platform remove callback returning void watchdog: rn5t618: Convert to platform remove callback returning void watchdog: rti: Convert to platform remove callback returning void watchdog: s3c2410: Convert to platform remove callback returning void watchdog: sa1100: Convert to platform remove callback returning void watchdog: sch311x: Convert to platform remove callback returning void watchdog: shwdt: Convert to platform remove callback returning void watchdog: st_lpc: Convert to platform remove callback returning void watchdog: stmp3xxx_rtc: Convert to platform remove callback returning void watchdog: wm8350: Convert to platform remove callback returning void drivers/watchdog/acquirewdt.c | 6 ++---- drivers/watchdog/advantechwdt.c | 6 ++---- drivers/watchdog/ar7_wdt.c | 5 ++--- drivers/watchdog/at91rm9200_wdt.c | 6 ++---- drivers/watchdog/ath79_wdt.c | 5 ++--- drivers/watchdog/bcm2835_wdt.c | 6 ++---- drivers/watchdog/bcm47xx_wdt.c | 6 ++---- drivers/watchdog/bcm_kona_wdt.c | 6 ++---- drivers/watchdog/cpwd.c | 6 ++---- drivers/watchdog/dw_wdt.c | 6 ++---- drivers/watchdog/gef_wdt.c | 6 ++---- drivers/watchdog/geodewdt.c | 5 ++--- drivers/watchdog/ib700wdt.c | 5 ++--- drivers/watchdog/ie6xx_wdt.c | 6 ++---- drivers/watchdog/lpc18xx_wdt.c | 6 ++---- drivers/watchdog/mtx-1_wdt.c | 5 ++--- drivers/watchdog/nic7018_wdt.c | 6 ++---- drivers/watchdog/nv_tco.c | 6 ++---- drivers/watchdog/omap_wdt.c | 6 ++---- drivers/watchdog/orion_wdt.c | 5 ++--- drivers/watchdog/rc32434_wdt.c | 5 ++--- drivers/watchdog/rdc321x_wdt.c | 6 ++---- drivers/watchdog/renesas_wdt.c | 6 ++---- drivers/watchdog/riowd.c | 6 ++---- drivers/watchdog/rn5t618_wdt.c | 6 ++---- drivers/watchdog/rti_wdt.c | 6 ++---- drivers/watchdog/s3c2410_wdt.c | 9 ++++----- drivers/watchdog/sa1100_wdt.c | 6 ++---- drivers/watchdog/sch311x_wdt.c | 5 ++--- drivers/watchdog/shwdt.c | 6 ++---- drivers/watchdog/st_lpc_wdt.c | 6 ++---- drivers/watchdog/stmp3xxx_rtc_wdt.c | 5 ++--- drivers/watchdog/wm8350_wdt.c | 5 ++--- 33 files changed, 68 insertions(+), 123 deletions(-) base-commit: 2eb29d59ddf02e39774abfb60b2030b0b7e27c1f