Patch "loop: Use pr_warn_once() for loop_control_remove() warning" 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

    loop: Use pr_warn_once() for loop_control_remove() warning

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:
     loop-use-pr_warn_once-for-loop_control_remove-warnin.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 bbee43f75fdd61fe74c94ae7a15791ad33e4bd50
Author: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date:   Mon Nov 29 19:00:43 2021 +0900

    loop: Use pr_warn_once() for loop_control_remove() warning
    
    [ Upstream commit e3f9387aea67742b9d1f4de8e5bb2fd08a8a4584 ]
    
    kernel test robot reported that RCU stall via printk() flooding is
    possible [1] when stress testing.
    
    Link: https://lkml.kernel.org/r/20211129073709.GA18483@xsang-OptiPlex-9020 [1]
    Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
    Reviewed-by: Christoph Hellwig <hch@xxxxxx>
    Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index dfc72a1f6500d..c00ae30fde89e 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2429,7 +2429,7 @@ static int loop_control_remove(int idx)
 	int ret;
 
 	if (idx < 0) {
-		pr_warn("deleting an unspecified loop device is not supported.\n");
+		pr_warn_once("deleting an unspecified loop device is not supported.\n");
 		return -EINVAL;
 	}