commit
541cd3ee00a4fe975b22fac6a3bc846bacef37f7 ("phylib: Fix deadlock
on resume") caused TI DaVinci EMAC ethernet driver to oops upon resume:
PM: resume of devices complete after 237.098 msecs
Restarting tasks ... done.
kernel BUG at kernel/workqueue.c:354!
Unable to handle kernel NULL pointer dereference at virtual address
00000000
[...]
Backtrace:
[<
c002c598>] (__bug+0x0/0x2c) from [<
c0052a54>] (queue_delayed_work_on+0x74/0xf8)
[<
c00529e0>] (queue_delayed_work_on+0x0/0xf8) from [<
c0052b30>] (queue_delayed_work+0x2c/0x30)
The oops pops up because TI DaVinci EMAC driver detaches PHY on
suspend and attaches it back on resume. Attaching makes phylib call
phy_start_machine() that initializes a workqueue. On the other hand,
PHY's resume routine will call phy_start_machine() again, and that
will cause the oops since we just destroyed the already scheduled
workqueue.
This patch fixes the issue by moving workqueue initialization to
phy_device_create().
p.s. We don't see this oops with ucc_geth and gianfar drivers because
they perform a fine-grained suspend, i.e. they just stop the PHYs
without detaching.
Reported-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
static void phy_change(struct work_struct *work);
-static void phy_state_machine(struct work_struct *work);
/**
* phy_start_machine - start PHY state machine tracking
{
phydev->adjust_state = handler;
- INIT_DELAYED_WORK(&phydev->state_queue, phy_state_machine);
schedule_delayed_work(&phydev->state_queue, HZ);
}
* phy_state_machine - Handle the state machine
* @work: work_struct that describes the work to be done
*/
-static void phy_state_machine(struct work_struct *work)
+void phy_state_machine(struct work_struct *work)
{
struct delayed_work *dwork = to_delayed_work(work);
struct phy_device *phydev =
dev->state = PHY_DOWN;
mutex_init(&dev->lock);
+ INIT_DELAYED_WORK(&dev->state_queue, phy_state_machine);
return dev;
}
int phy_driver_register(struct phy_driver *new_driver);
void phy_prepare_link(struct phy_device *phydev,
void (*adjust_link)(struct net_device *));
+void phy_state_machine(struct work_struct *work);
void phy_start_machine(struct phy_device *phydev,
void (*handler)(struct net_device *));
void phy_stop_machine(struct phy_device *phydev);