diff options
| author | Stanislaw Gruszka <sgruszka@redhat.com> | 2014-02-19 10:29:01 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-03-05 17:13:49 +0100 |
| commit | bdb95b2e48479c4c7bcf522e3605d1a2f8ae8438 (patch) | |
| tree | 7f2e2f754d31eb242f2926fc511a7716a84c3cf2 /drivers/usb/host/ehci-hcd.c | |
| parent | b2f20b15e450bb7f1b7f8c67647dc3815b127ca5 (diff) | |
| download | lwn-bdb95b2e48479c4c7bcf522e3605d1a2f8ae8438.tar.gz lwn-bdb95b2e48479c4c7bcf522e3605d1a2f8ae8438.zip | |
usb: ehci: fix deadlock when threadirqs option is used
commit a1227f3c1030e96ebc51d677d2f636268845c5fb upstream.
ehci_irq() and ehci_hrtimer_func() can deadlock on ehci->lock when
threadirqs option is used. To prevent the deadlock use
spin_lock_irqsave() in ehci_irq().
This change can be reverted when hrtimer callbacks become threaded.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'drivers/usb/host/ehci-hcd.c')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 86ab9fd9fe9e..784f6242b70e 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -682,8 +682,15 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) struct ehci_hcd *ehci = hcd_to_ehci (hcd); u32 status, masked_status, pcd_status = 0, cmd; int bh; + unsigned long flags; - spin_lock (&ehci->lock); + /* + * For threadirqs option we use spin_lock_irqsave() variant to prevent + * deadlock with ehci hrtimer callback, because hrtimer callbacks run + * in interrupt context even when threadirqs is specified. We can go + * back to spin_lock() variant when hrtimer callbacks become threaded. + */ + spin_lock_irqsave(&ehci->lock, flags); status = ehci_readl(ehci, &ehci->regs->status); @@ -701,7 +708,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* Shared IRQ? */ if (!masked_status || unlikely(ehci->rh_state == EHCI_RH_HALTED)) { - spin_unlock(&ehci->lock); + spin_unlock_irqrestore(&ehci->lock, flags); return IRQ_NONE; } @@ -819,7 +826,7 @@ dead: if (bh) ehci_work (ehci); - spin_unlock (&ehci->lock); + spin_unlock_irqrestore(&ehci->lock, flags); if (pcd_status) usb_hcd_poll_rh_status(hcd); return IRQ_HANDLED; |