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ARM: at91: pm: fix imbalanced reference counter for ethernet devices

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[ Upstream commit ccd4923d18d5698a5910d516646ce125b9155d47 ]

The of_find_device_by_node() function is returning a struct platform_device
object with the embedded struct device member's reference counter
incremented. This needs to be dropped when done with the platform device
returned by of_find_device_by_node().

at91_pm_eth_quirk_is_valid() calls of_find_device_by_node() on
suspend and resume path. On suspend it calls of_find_device_by_node() and
on resume and failure paths it drops the counter of
struct platform_device::dev.

In case ethernet device may not wakeup there is a put_device() on
at91_pm_eth_quirk_is_valid() which is wrong as it colides with
put_device() on resume path leading to the reference counter of struct
device embedded in struct platform_device to be messed, stack trace to be
displayed (after 5 consecutive suspend/resume cycles) and execution to
hang.

Along with this the error path of at91_pm_config_quirks() had been also
adapted to decrement propertly the reference counter of struct device
embedded in struct platform_device.

Fixes: b7fc72c633 ("ARM: at91: pm: add quirks for pm")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20230518062511.2988500-1-claudiu.beznea@microchip.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Claudiu Beznea 2023-05-18 09:25:11 +03:00 committed by Greg Kroah-Hartman
parent c97f30d215
commit 4b8ebe5393
1 changed files with 9 additions and 11 deletions
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20
arch/arm/mach-at91/pm.c
View File

@ -334,16 +334,14 @@ static bool at91_pm_eth_quirk_is_valid(struct at91_pm_quirk_eth *eth)
pdev = of_find_device_by_node(eth->np); pdev = of_find_device_by_node(eth->np);
if (!pdev) if (!pdev)
return false; return false;
/* put_device(eth->dev) is called at the end of suspend. */
eth->dev = &pdev->dev; eth->dev = &pdev->dev;
} }
/* No quirks if device isn't a wakeup source. */ /* No quirks if device isn't a wakeup source. */
if (!device_may_wakeup(eth->dev)) { if (!device_may_wakeup(eth->dev))
put_device(eth->dev);
return false; return false;
}
/* put_device(eth->dev) is called at the end of suspend. */
return true; return true;
} }
@ -439,14 +437,14 @@ static int at91_pm_config_quirks(bool suspend)
pr_err("AT91: PM: failed to enable %s clocks\n", pr_err("AT91: PM: failed to enable %s clocks\n",
j == AT91_PM_G_ETH ? "geth" : "eth"); j == AT91_PM_G_ETH ? "geth" : "eth");
} }
} else {
/*
* Release the reference to eth->dev taken in
* at91_pm_eth_quirk_is_valid().
*/
put_device(eth->dev);
eth->dev = NULL;
} }
/*
* Release the reference to eth->dev taken in
* at91_pm_eth_quirk_is_valid().
*/
put_device(eth->dev);
eth->dev = NULL;
} }
return ret; return ret;