Patch "iavf: fix potential deadlock on allocation failure" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iavf: fix potential deadlock on allocation failure

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iavf-fix-potential-deadlock-on-allocation-failure.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 12e395df5a6843bb928952b552875a3bb07bde10
Author: Jacob Keller <jacob.e.keller@xxxxxxxxx>
Date:   Mon Jul 10 13:41:27 2023 -0700

    iavf: fix potential deadlock on allocation failure
    
    [ Upstream commit a2f054c10bef0b54600ec9cb776508443e941343 ]
    
    In iavf_adminq_task(), if kzalloc() fails to allocate the event.msg_buf,
    the function will exit without releasing the adapter->crit_lock.
    
    This is unlikely, but if it happens, the next access to that mutex will
    deadlock.
    
    Fix this by moving the unlock to the end of the function, and adding a new
    label to allow jumping to the unlock portion of the function exit flow.
    
    Fixes: fc2e6b3b132a ("iavf: Rework mutexes for better synchronisation")
    Signed-off-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
    Tested-by: Rafal Romanowski <rafal.romanowski@xxxxxxxxx>
    Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index bcceb2ddfea63..1e349a90d21aa 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -2546,7 +2546,7 @@ static void iavf_adminq_task(struct work_struct *work)
 	event.buf_len = IAVF_MAX_AQ_BUF_SIZE;
 	event.msg_buf = kzalloc(event.buf_len, GFP_KERNEL);
 	if (!event.msg_buf)
-		goto out;
+		goto unlock;
 
 	do {
 		ret = iavf_clean_arq_element(hw, &event, &pending);
@@ -2561,7 +2561,6 @@ static void iavf_adminq_task(struct work_struct *work)
 		if (pending != 0)
 			memset(event.msg_buf, 0, IAVF_MAX_AQ_BUF_SIZE);
 	} while (pending);
-	mutex_unlock(&adapter->crit_lock);
 
 	if ((adapter->flags & IAVF_FLAG_SETUP_NETDEV_FEATURES)) {
 		if (adapter->netdev_registered ||
@@ -2619,6 +2618,8 @@ static void iavf_adminq_task(struct work_struct *work)
 
 freedom:
 	kfree(event.msg_buf);
+unlock:
+	mutex_unlock(&adapter->crit_lock);
 out:
 	/* re-enable Admin queue interrupt cause */
 	iavf_misc_irq_enable(adapter);