diff options
| author | Rafael Mendonca <rafaelmendsr@gmail.com> | 2022-09-30 19:40:58 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-07 12:07:24 +0100 |
| commit | 35a27f38b4e5c6a174edbbec72908b279973071a (patch) | |
| tree | bf24f159e501a45d5faf092ac9d2732c87ddc93c | |
| parent | 9977cb7af5a8f4738198b020436e2e56c5cd721e (diff) | |
uio: uio_dmem_genirq: Fix deadlock between irq config and handling
[ Upstream commit 118b918018175d9fcd8db667f905012e986cc2c9 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/uio/uio_dmem_genirq.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c index c25a6bcb2d21..b4b7fa05b29b 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -113,8 +113,10 @@ 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; } @@ -128,7 +130,8 @@ 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); |