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net: wwan: mhi_wwan_ctrl: Fix possible deadlock

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Lockdep detected possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&mhiwwan->rx_lock);
                               local_irq_disable();
                               lock(&mhi_cntrl->pm_lock);
                               lock(&mhiwwan->rx_lock);
   <Interrupt>
     lock(&mhi_cntrl->pm_lock);

  *** DEADLOCK ***

To prevent this we need to disable the soft-interrupts when taking
the rx_lock.

Cc: stable@vger.kernel.org
Fixes: fa588eba63 ("net: Add Qcom WWAN control driver")
Reported-by: Thomas Perrot <thomas.perrot@bootlin.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Loic Poulain 2021-08-06 12:35:09 +02:00 committed by David S. Miller
parent 47fac45600
commit 34737e1320
1 changed files with 6 additions and 6 deletions

12
drivers/net/wwan/mhi_wwan_ctrl.c
View File

@ -41,14 +41,14 @@ struct mhi_wwan_dev {
/* Increment RX budget and schedule RX refill if necessary */
static void mhi_wwan_rx_budget_inc(struct mhi_wwan_dev *mhiwwan)
{
spin_lock(&mhiwwan->rx_lock);
spin_lock_bh(&mhiwwan->rx_lock);
mhiwwan->rx_budget++;
if (test_bit(MHI_WWAN_RX_REFILL, &mhiwwan->flags))
schedule_work(&mhiwwan->rx_refill);
spin_unlock(&mhiwwan->rx_lock);
spin_unlock_bh(&mhiwwan->rx_lock);
}
/* Decrement RX budget if non-zero and return true on success */
@ -56,7 +56,7 @@ static bool mhi_wwan_rx_budget_dec(struct mhi_wwan_dev *mhiwwan)
{
bool ret = false;
spin_lock(&mhiwwan->rx_lock);
spin_lock_bh(&mhiwwan->rx_lock);
if (mhiwwan->rx_budget) {
mhiwwan->rx_budget--;
@ -64,7 +64,7 @@ static bool mhi_wwan_rx_budget_dec(struct mhi_wwan_dev *mhiwwan)
ret = true;
}
spin_unlock(&mhiwwan->rx_lock);
spin_unlock_bh(&mhiwwan->rx_lock);
return ret;
}
@ -130,9 +130,9 @@ static void mhi_wwan_ctrl_stop(struct wwan_port *port)
{
struct mhi_wwan_dev *mhiwwan = wwan_port_get_drvdata(port);
spin_lock(&mhiwwan->rx_lock);
spin_lock_bh(&mhiwwan->rx_lock);
clear_bit(MHI_WWAN_RX_REFILL, &mhiwwan->flags);
spin_unlock(&mhiwwan->rx_lock);
spin_unlock_bh(&mhiwwan->rx_lock);
cancel_work_sync(&mhiwwan->rx_refill);