summaryrefslogtreecommitdiff
path: root/drivers/uio
diff options
context:
space:
mode:
authorRafael Mendonca <rafaelmendsr@gmail.com>2022-10-01 01:40:58 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-11-10 20:54:29 +0300
commit118b918018175d9fcd8db667f905012e986cc2c9 (patch)
treedec5fe0c7be7fd898823bf78a804311604fba03c /drivers/uio
parent9de255c461d1b3f0242b3ad1450c3323a3e00b34 (diff)
downloadlinux-118b918018175d9fcd8db667f905012e986cc2c9.tar.xz
uio: uio_dmem_genirq: Fix deadlock between irq config and handling
This fixes a concurrency issue addressed in commit 34cb27528398 ("UIO: Fix concurrency issue"): "In a SMP case there was a race condition issue between Uio_pdrv_genirq_irqcontrol() running on one CPU and irq handler on another CPU. Fix it by spin_locking shared resources access inside irq handler." The implementation of "uio_dmem_genirq" was based on "uio_pdrv_genirq" and it is used in a similar manner to the "uio_pdrv_genirq" driver with respect to interrupt configuration and handling. At the time "uio_dmem_genirq" was merged, both had the same implementation of the 'uio_info' handlers irqcontrol() and handler(), thus, both had the same concurrency issue mentioned by the above commit. However, the above patch was only applied to the "uio_pdrv_genirq" driver. Split out from commit 34cb27528398 ("UIO: Fix concurrency issue"). Fixes: 0a0c3b5a24bd ("Add new uio device for dynamic memory allocation") Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com> Link: https://lore.kernel.org/r/20220930224100.816175-3-rafaelmendsr@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/uio')
-rw-r--r--drivers/uio/uio_dmem_genirq.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
index cb283ee36eaa..792c3e9c9ce5 100644
--- a/drivers/uio/uio_dmem_genirq.c
+++ b/drivers/uio/uio_dmem_genirq.c
@@ -110,8 +110,10 @@ static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
* remember the state so we can allow user space to enable it later.
*/
+ spin_lock(&priv->lock);
if (!test_and_set_bit(0, &priv->flags))
disable_irq_nosync(irq);
+ spin_unlock(&priv->lock);
return IRQ_HANDLED;
}
@@ -125,7 +127,8 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
* in the interrupt controller, but keep track of the
* state to prevent per-irq depth damage.
*
- * Serialize this operation to support multiple tasks.
+ * Serialize this operation to support multiple tasks and concurrency
+ * with irq handler on SMP systems.
*/
spin_lock_irqsave(&priv->lock, flags);