[PATCH 6.9 084/374] dmaengine: idxd: Avoid unnecessary destruction of file_ida

Greg Kroah-Hartman
2024-06-06T14:08:54Z

From: Fenghua Yu <fenghua.yu@intel.com>

[ Upstream commit 76e43fa6a456787bad31b8d0daeabda27351a480 ]

file_ida is allocated during cdev open and is freed accordingly
during cdev release. This sequence is guaranteed by driver file
operations. Therefore, there is no need to destroy an already empty
file_ida when the WQ cdev is removed.

Worse, ida_free() in cdev release may happen after destruction of
file_ida per WQ cdev. This can lead to accessing an id in file_ida
after it has been destroyed, resulting in a kernel panic.

Remove ida_destroy(&file_ida) to address these issues.

Fixes: e6fd6d7e5f0f ("dmaengine: idxd: add a device to represent the file opened")
Signed-off-by: Lijun Pan <lijun.pan@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20240130013954.2024231-1-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/idxd/cdev.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 39935071174a3..fd9bbee4cc42f 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -577,7 +577,6 @@ void idxd_wq_del_cdev(struct idxd_wq *wq)
struct idxd_cdev *idxd_cdev;

idxd_cdev = wq->idxd_cdev;
- ida_destroy(&file_ida);
wq->idxd_cdev = NULL;
cdev_device_del(&idxd_cdev->cdev, cdev_dev(idxd_cdev));
put_device(cdev_dev(idxd_cdev));
--
2.43.0