This is a note to let you know that I've just added the patch titled hv_balloon: rate-limit "Unhandled message" 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: hv_balloon-rate-limit-unhandled-message-warning.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 154a5e84ddc71ea418246fd24205c175716b2160 Author: Anssi Hannula <anssi.hannula@xxxxxxxxxx> Date: Tue Feb 22 16:14:00 2022 +0200 hv_balloon: rate-limit "Unhandled message" warning [ Upstream commit 1d7286729aa616772be334eb908e11f527e1e291 ] For a couple of times I have encountered a situation where hv_balloon: Unhandled message: type: 12447 is being flooded over 1 million times per second with various values, filling the log and consuming cycles, making debugging difficult. Add rate limiting to the message. Most other Hyper-V drivers already have similar rate limiting in their message callbacks. The cause of the floods in my case was probably fixed by 96d9d1fa5cd5 ("Drivers: hv: balloon: account for vmbus packet header in max_pkt_size"). Fixes: 9aa8b50b2b3d ("Drivers: hv: Add Hyper-V balloon driver") Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxxxxxx> Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220222141400.98160-1-anssi.hannula@xxxxxxxxxx Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index f2d05bff4245..439f99b8b5de 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1563,7 +1563,7 @@ static void balloon_onchannelcallback(void *context) break; default: - pr_warn("Unhandled message: type: %d\n", dm_hdr->type); + pr_warn_ratelimited("Unhandled message: type: %d\n", dm_hdr->type); } }