github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-12 20:53:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

watchdog: msc313e: Fix clock leak and spurious timer in settimeout()

Browse Source 
msc313e_wdt_settimeout() unconditionally calls msc313e_wdt_start() which
introduces two severe bugs:

1. If the watchdog is already active, calling start() again will
   increase the reference count of the clock again.  However stop() is
   only called once, the reference count is unbalance.
2. If the watchdog is stopped, calling settimeout() will start
   the hardware timer accidentally.

Factor out the register-writing logic into a helper function.  Only call
it in settimeout() if the watchdog is running.  Otherwise, simply update
`wdev->timeout`.

Fixes: e9800b7994 ("watchdog: Add Mstar MSC313e WDT driver")
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://patch.msgid.link/20260828161348.13212-4-tzungbi@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Tzung-Bi Shih 2026-08-29 00:13:42 +08:00 committed by Guenter Roeck
parent 3c73a37f5e
commit 3db30f3159
1 changed files with 16 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/watchdog/msc313e_wdt.c
View File

@ -31,20 +31,26 @@ struct msc313e_wdt_priv {
struct clk *clk;
};
static void msc313e_wdt_set_hw_timeout(struct msc313e_wdt_priv *priv,
unsigned int timeout)
{
u32 t = timeout * clk_get_rate(priv->clk);
writew(t & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
writew((t >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
writew(1, priv->base + REG_WDT_CLR);
}
static int msc313e_wdt_start(struct watchdog_device *wdev)
{
struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
u32 timeout;
int err;
err = clk_prepare_enable(priv->clk);
if (err)
return err;
timeout = wdev->timeout * clk_get_rate(priv->clk);
writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
writew(1, priv->base + REG_WDT_CLR);
msc313e_wdt_set_hw_timeout(priv, wdev->timeout);
return 0;
}
@ -69,9 +75,13 @@ static int msc313e_wdt_stop(struct watchdog_device *wdev)
static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)
{
struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
wdev->timeout = new_time;
return msc313e_wdt_start(wdev);
if (watchdog_hw_running(wdev) || watchdog_active(wdev))
msc313e_wdt_set_hw_timeout(priv, wdev->timeout);
return 0;
}
static const struct watchdog_info msc313e_wdt_ident = {