6.12-stable review patch. If anyone has any objections, please let me know.
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From: Pranjal Ramajor Asha Kanojiya quic_pkanojiy@quicinc.com
[ Upstream commit 52e59f7740ba23bbb664914967df9a00208ca10c ]
Two threads of the same process can potential read and write parallelly to head and tail pointers of the same DBC request queue. This could lead to a race condition and corrupt the DBC request queue.
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Pranjal Ramajor Asha Kanojiya quic_pkanojiy@quicinc.com Signed-off-by: Youssef Samir youssef.abdulrahman@oss.qualcomm.com Reviewed-by: Jeff Hugo jeff.hugo@oss.qualcomm.com Reviewed-by: Carl Vanderlip carl.vanderlip@oss.qualcomm.com [jhugo: Add fixes tag] Signed-off-by: Jeff Hugo jeff.hugo@oss.qualcomm.com Link: https://lore.kernel.org/r/20251007061837.206132-1-youssef.abdulrahman@oss.qu... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/accel/qaic/qaic.h | 2 ++ drivers/accel/qaic/qaic_data.c | 12 ++++++++++-- drivers/accel/qaic/qaic_drv.c | 3 +++ 3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/accel/qaic/qaic.h b/drivers/accel/qaic/qaic.h index 02561b6cecc64..2d7b3af09e284 100644 --- a/drivers/accel/qaic/qaic.h +++ b/drivers/accel/qaic/qaic.h @@ -91,6 +91,8 @@ struct dma_bridge_chan { * response queue's head and tail pointer of this DBC. */ void __iomem *dbc_base; + /* Synchronizes access to Request queue's head and tail pointer */ + struct mutex req_lock; /* Head of list where each node is a memory handle queued in request queue */ struct list_head xfer_list; /* Synchronizes DBC readers during cleanup */ diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index 43aba57b48f05..265eeb4e156fc 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -1357,13 +1357,17 @@ static int __qaic_execute_bo_ioctl(struct drm_device *dev, void *data, struct dr goto release_ch_rcu; }
+ ret = mutex_lock_interruptible(&dbc->req_lock); + if (ret) + goto release_ch_rcu; + head = readl(dbc->dbc_base + REQHP_OFF); tail = readl(dbc->dbc_base + REQTP_OFF);
if (head == U32_MAX || tail == U32_MAX) { /* PCI link error */ ret = -ENODEV; - goto release_ch_rcu; + goto unlock_req_lock; }
queue_level = head <= tail ? tail - head : dbc->nelem - (head - tail); @@ -1371,11 +1375,12 @@ static int __qaic_execute_bo_ioctl(struct drm_device *dev, void *data, struct dr ret = send_bo_list_to_device(qdev, file_priv, exec, args->hdr.count, is_partial, dbc, head, &tail); if (ret) - goto release_ch_rcu; + goto unlock_req_lock;
/* Finalize commit to hardware */ submit_ts = ktime_get_ns(); writel(tail, dbc->dbc_base + REQTP_OFF); + mutex_unlock(&dbc->req_lock);
update_profiling_data(file_priv, exec, args->hdr.count, is_partial, received_ts, submit_ts, queue_level); @@ -1383,6 +1388,9 @@ static int __qaic_execute_bo_ioctl(struct drm_device *dev, void *data, struct dr if (datapath_polling) schedule_work(&dbc->poll_work);
+unlock_req_lock: + if (ret) + mutex_unlock(&dbc->req_lock); release_ch_rcu: srcu_read_unlock(&dbc->ch_lock, rcu_id); unlock_dev_srcu: diff --git a/drivers/accel/qaic/qaic_drv.c b/drivers/accel/qaic/qaic_drv.c index 10e711c96a670..cb606c4bb8511 100644 --- a/drivers/accel/qaic/qaic_drv.c +++ b/drivers/accel/qaic/qaic_drv.c @@ -422,6 +422,9 @@ static struct qaic_device *create_qdev(struct pci_dev *pdev, const struct pci_de return NULL; init_waitqueue_head(&qdev->dbc[i].dbc_release); INIT_LIST_HEAD(&qdev->dbc[i].bo_lists); + ret = drmm_mutex_init(drm, &qdev->dbc[i].req_lock); + if (ret) + return NULL; }
return qdev;