Re: [PATCH] ARM: at91: pm: fix imbalanced reference counter for ethernet devices
From: Nicolas Ferre
Date: Mon May 22 2023 - 05:07:56 EST
On 18/05/2023 at 08:25, Claudiu Beznea wrote:
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, the following
stack trace to be displayed (after 5 consecutive suspend/resume cycles)
and the execution to hang:
WARNING: CPU: 0 PID: 378 at lib/refcount.c:25 0xc07ffc08
refcount_t: addition on 0; use-after-free.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Not tainted 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c07ffc08>]
Function entered at [<c07ffc08>] from [<c045fe88>]
Function entered at [<c045fe88>] from [<c046004c>]
Function entered at [<c046004c>] from [<c0141e94>]
Function entered at [<c0141e94>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at lib/refcount.c:28 0xc045fef4
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c045fef4>]
Function entered at [<c045fef4>] from [<c046004c>]
Function entered at [<c046004c>] from [<c0141e94>]
Function entered at [<c0141e94>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at lib/refcount.c:22 0xc07ffbf4
refcount_t: saturated; leaking memory.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c07ffbf4>]
Function entered at [<c07ffbf4>] from [<c045eaa0>]
Function entered at [<c045eaa0>] from [<c045fcc4>]
Function entered at [<c045fcc4>] from [<c045fee4>]
Function entered at [<c045fee4>] from [<c046004c>]
Function entered at [<c046004c>] from [<c0141e94>]
Function entered at [<c0141e94>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at kernel/irq/chip.c:241 0xc014be2c
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c011637c>]
Function entered at [<c011637c>] from [<c014be2c>]
Function entered at [<c014be2c>] from [<c014f808>]
Function entered at [<c014f808>] from [<c0460050>]
Function entered at [<c0460050>] from [<c0141e94>]
Function entered at [<c0141e94>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
at_xdmac e1200000.dma-controller: controller in mem2mem mode.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at lib/kobject.c:634 0xc07ffbe8
kobject: '$���"����L��L��' (a3ba4c7d): is not initialized, yet kobject_get() is being called.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c07ffbe8>]
Function entered at [<c07ffbe8>] from [<c0460300>]
Function entered at [<c0460300>] from [<c0460634>]
Function entered at [<c0460634>] from [<c0141ed4>]
Function entered at [<c0141ed4>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at lib/kobject.c:728 0xc07ffd7c
kobject: '$���"����L��L��' (a3ba4c7d): is not initialized, yet kobject_put() is being called.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c07ffd7c>]
Function entered at [<c07ffd7c>] from [<c0460384>]
Function entered at [<c0460384>] from [<c0460634>]
Function entered at [<c0460634>] from [<c0141ed4>]
Function entered at [<c0141ed4>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 378 at lib/kobject.c:634 0xc07ffbe8
kobject: '�Z����@Ą�?��8�H�Ĕ����UC�' (6407eb2a): is not initialized, yet kobject_get() is being called.
Modules linked in:
CPU: 0 PID: 378 Comm: sh Tainted: G W 6.1.22-linux4microchip-2023.04-rc3+ #7
Hardware name: Microchip SAMA7
Function entered at [<c010c134>] from [<c010993c>]
Function entered at [<c010993c>] from [<c0823754>]
Function entered at [<c0823754>] from [<c01162ac>]
Function entered at [<c01162ac>] from [<c0116340>]
Function entered at [<c0116340>] from [<c07ffbe8>]
Function entered at [<c07ffbe8>] from [<c0460300>]
Function entered at [<c0460300>] from [<c0460634>]
Function entered at [<c0460634>] from [<c0141ed4>]
Function entered at [<c0141ed4>] from [<c0142448>]
Function entered at [<c0142448>] from [<c0140da8>]
Function entered at [<c0140da8>] from [<c023dba0>]
Function entered at [<c023dba0>] from [<c01d0700>]
Function entered at [<c01d0700>] from [<c01d092c>]
Function entered at [<c01d092c>] from [<c0100060>]
Exception stack(0xe0e81fa8 to 0xe0e81ff0)
1fa0: 00000004 0057c668 00000001 0057c668 00000004 00000000
1fc0: 00000004 0057c668 b6ecaba0 00000004 b6f4c0e0 b6ecb15c 00000000 00000000
1fe0: 005456f0 beb3a788 b6dcfac4 b6e3bab8
---[ end trace 0000000000000000 ]---
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: b7fc72c63399 ("ARM: at91: pm: add quirks for pm")
Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Thanks for this fix Claudiu. Best regards,
Nicolas
---
arch/arm/mach-at91/pm.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index 60dc56d8acfb..437dd0352fd4 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -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);
if (!pdev)
return false;
+ /* put_device(eth->dev) is called at the end of suspend. */
eth->dev = &pdev->dev;
}
/* No quirks if device isn't a wakeup source. */
- if (!device_may_wakeup(eth->dev)) {
- put_device(eth->dev);
+ if (!device_may_wakeup(eth->dev))
return false;
- }
- /* put_device(eth->dev) is called at the end of suspend. */
return true;
}
@@ -439,14 +437,14 @@ static int at91_pm_config_quirks(bool suspend)
pr_err("AT91: PM: failed to enable %s clocks\n",
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;
--
Nicolas Ferre