[PATCH net-next] net: napi: remove useless stack trace

[PATCH net-next] net: napi: remove useless stack trace

[Eric Dumazet]

Whenever a buggy NAPI driver returns more than its budget,
we emit a stack trace that is of no use, since it does not
tell which driver is buggy.

Instead, emit a message giving the function name, and a
descriptive message.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/dev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6bc2388141f6fd7c66c0e8349514a326e5106db2..cea7fc1716caf9dbe8fcfcb5c5eec0ed21e20775 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6683,7 +6683,9 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 		trace_napi_poll(n, work, weight);
 	}
 
-	WARN_ON_ONCE(work > weight);
+	if (unlikely(work > weight))
+		pr_err_once("NAPI poll function %pS returned %d, exceeding its budget of %d.\n",
+			    n->poll, work, weight);
 
 	if (likely(work < weight))
 		goto out_unlock;
-- 
2.27.0.290.gba653c62da-goog

Re: [PATCH net-next] net: napi: remove useless stack trace

[David Miller]

From: Eric Dumazet <edumazet@google.com>
Date: Wed, 17 Jun 2020 09:40:51 -0700

> Whenever a buggy NAPI driver returns more than its budget,
> we emit a stack trace that is of no use, since it does not
> tell which driver is buggy.
> 
> Instead, emit a message giving the function name, and a
> descriptive message.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thanks Eric.