Livepatch timeouts were reported due to busy vhost_worker() kthreads.
Now that cond_resched() can do livepatch task switching, use
cond_resched() in vhost_worker().  That's the better way to
conditionally call schedule() anyway.

Reported-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Link: https://lkml.kernel.org/lkml/20230120-vhost-klp-switching-v1-0-7c2b65519c43@kernel.org
Tested-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 drivers/vhost/vhost.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 43c9770b86e5..87e3cf12da1c 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -363,8 +363,7 @@ static int vhost_worker(void *data)
 			kcov_remote_start_common(dev->kcov_handle);
 			work->fn(work);
 			kcov_remote_stop();
-			if (need_resched())
-				schedule();
+			cond_resched();
 		}
 	}
 	kthread_unuse_mm(dev->mm);
-- 
2.39.1

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     05bfb338fa8dd40b008ce443e397fc374f6bd107
Gitweb:        https://git.kernel.org/tip/05bfb338fa8dd40b008ce443e397fc374f6bd107
Author:        Josh Poimboeuf <jpoimboe@kernel.org>
AuthorDate:    Fri, 24 Feb 2023 08:50:01 -08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 22 Mar 2023 17:09:29 +01:00

vhost: Fix livepatch timeouts in vhost_worker()

Livepatch timeouts were reported due to busy vhost_worker() kthreads.
Now that cond_resched() can do livepatch task switching, use
cond_resched() in vhost_worker().  That's the better way to
conditionally call schedule() anyway.

Reported-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Link: https://lore.kernel.org/r/509f6ea6fe6505f0a75a66026ba531c765ef922f.1677257135.git.jpoimboe@kernel.org
---
 drivers/vhost/vhost.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index f11bdbe..822fbdb 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -363,8 +363,7 @@ static int vhost_worker(void *data)
 			kcov_remote_start_common(dev->kcov_handle);
 			work->fn(work);
 			kcov_remote_stop();
-			if (need_resched())
-				schedule();
+			cond_resched();
 		}
 	}
 	kthread_unuse_mm(dev->mm);