Commit d0212f09 authored by Zou Wei's avatar Zou Wei Committed by Wim Van Sebroeck

watchdog: Fix possible use-after-free by calling del_timer_sync()

This driver's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.
Reported-by: default avatarHulk Robot <hulkci@huawei.com>
Signed-off-by: default avatarZou Wei <zou_wei@huawei.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarVladimir Zapolskiy <vz@mleia.com>
Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.comSigned-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
parent 90b7c141
...@@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) ...@@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev)
struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev); struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);
dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
del_timer(&lpc18xx_wdt->timer); del_timer_sync(&lpc18xx_wdt->timer);
return 0; return 0;
} }
......
...@@ -166,7 +166,7 @@ static void wdt_startup(void) ...@@ -166,7 +166,7 @@ static void wdt_startup(void)
static void wdt_turnoff(void) static void wdt_turnoff(void)
{ {
/* Stop the timer */ /* Stop the timer */
del_timer(&timer); del_timer_sync(&timer);
wdt_change(WDT_DISABLE); wdt_change(WDT_DISABLE);
......
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