* [PATCH net 1/2] net: phy: don't use locking in phy_is_started
2019-02-13 19:10 [PATCH net 0/2] net: phy: fix locking issue Heiner Kallweit
@ 2019-02-13 19:11 ` Heiner Kallweit
2019-02-14 4:13 ` Florian Fainelli
2019-02-13 19:12 ` [PATCH net 2/2] net: phy: fix potential race in the phylib state machine Heiner Kallweit
2019-02-14 17:05 ` [PATCH net 0/2] net: phy: fix locking issue David Miller
2 siblings, 1 reply; 6+ messages in thread
From: Heiner Kallweit @ 2019-02-13 19:11 UTC (permalink / raw)
To: Andrew Lunn, Florian Fainelli, David Miller
Cc: Russell King - ARM Linux, netdev@vger.kernel.org
Russell suggested to remove the locking from phy_is_started() because
the read is atomic anyway and actually the locking may be more
misleading.
Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Suggested-by: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
drivers/net/phy/phy.c | 11 +++++------
include/linux/phy.h | 15 +--------------
2 files changed, 6 insertions(+), 20 deletions(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index ca5e0c0f018c..602816d70281 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -553,7 +553,7 @@ int phy_start_aneg(struct phy_device *phydev)
if (err < 0)
goto out_unlock;
- if (__phy_is_started(phydev)) {
+ if (phy_is_started(phydev)) {
if (phydev->autoneg == AUTONEG_ENABLE) {
err = phy_check_link_status(phydev);
} else {
@@ -709,7 +709,7 @@ void phy_stop_machine(struct phy_device *phydev)
cancel_delayed_work_sync(&phydev->state_queue);
mutex_lock(&phydev->lock);
- if (__phy_is_started(phydev))
+ if (phy_is_started(phydev))
phydev->state = PHY_UP;
mutex_unlock(&phydev->lock);
}
@@ -839,15 +839,14 @@ EXPORT_SYMBOL(phy_stop_interrupts);
*/
void phy_stop(struct phy_device *phydev)
{
- mutex_lock(&phydev->lock);
-
- if (!__phy_is_started(phydev)) {
+ if (!phy_is_started(phydev)) {
WARN(1, "called from state %s\n",
phy_state_to_str(phydev->state));
- mutex_unlock(&phydev->lock);
return;
}
+ mutex_lock(&phydev->lock);
+
if (phy_interrupt_is_valid(phydev))
phy_disable_interrupts(phydev);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index ef20aeea10cc..127fcc9c3778 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -674,26 +674,13 @@ phy_lookup_setting(int speed, int duplex, const unsigned long *mask,
size_t phy_speeds(unsigned int *speeds, size_t size,
unsigned long *mask);
-static inline bool __phy_is_started(struct phy_device *phydev)
-{
- WARN_ON(!mutex_is_locked(&phydev->lock));
-
- return phydev->state >= PHY_UP;
-}
-
/**
* phy_is_started - Convenience function to check whether PHY is started
* @phydev: The phy_device struct
*/
static inline bool phy_is_started(struct phy_device *phydev)
{
- bool started;
-
- mutex_lock(&phydev->lock);
- started = __phy_is_started(phydev);
- mutex_unlock(&phydev->lock);
-
- return started;
+ return phydev->state >= PHY_UP;
}
void phy_resolve_aneg_linkmode(struct phy_device *phydev);
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH net 2/2] net: phy: fix potential race in the phylib state machine
2019-02-13 19:10 [PATCH net 0/2] net: phy: fix locking issue Heiner Kallweit
2019-02-13 19:11 ` [PATCH net 1/2] net: phy: don't use locking in phy_is_started Heiner Kallweit
@ 2019-02-13 19:12 ` Heiner Kallweit
2019-02-14 4:13 ` Florian Fainelli
2019-02-14 17:05 ` [PATCH net 0/2] net: phy: fix locking issue David Miller
2 siblings, 1 reply; 6+ messages in thread
From: Heiner Kallweit @ 2019-02-13 19:12 UTC (permalink / raw)
To: Andrew Lunn, Florian Fainelli, David Miller
Cc: Russell King - ARM Linux, netdev@vger.kernel.org
Russell reported the following race in the phylib state machine
(quoting from his mail):
if (phy_polling_mode(phydev) && phy_is_started(phydev))
phy_queue_state_machine(phydev, PHY_STATE_TIME);
state = PHY_UP
thread 0 thread 1
phy_disconnect()
+-phy_is_started()
phy_is_started() |
`-phy_stop()
+-phydev->state = PHY_HALTED
`-phy_stop_machine()
`-cancel_delayed_work_sync()
phy_queue_state_machine()
`-mod_delayed_work()
At this point, the phydev->state_queue() has been added back onto the
system workqueue despite phy_stop_machine() having been called and
cancel_delayed_work_sync() called on it.
Fix this by protecting the complete operation in thread 0.
Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Reported-by: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
drivers/net/phy/phy.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 602816d70281..c5675df5fc6f 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -985,8 +985,10 @@ void phy_state_machine(struct work_struct *work)
* state machine would be pointless and possibly error prone when
* called from phy_disconnect() synchronously.
*/
+ mutex_lock(&phydev->lock);
if (phy_polling_mode(phydev) && phy_is_started(phydev))
phy_queue_state_machine(phydev, PHY_STATE_TIME);
+ mutex_unlock(&phydev->lock);
}
/**
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread