This is a note to let you know that I've just added the patch titled
libbpf: Fix bail out from 'ringbuf_process_ring()' on error
to the 5.11-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:
libbpf-fix-bail-out-from-ringbuf_process_ring-on-error.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6032ebb54c60cae24329f6aba3ce0c1ca8ad6abe Mon Sep 17 00:00:00 2001
From: Pedro Tammela <pctammela@xxxxxxxxx>
Date: Thu, 25 Mar 2021 12:01:15 -0300
Subject: libbpf: Fix bail out from 'ringbuf_process_ring()' on error
From: Pedro Tammela <pctammela@xxxxxxxxx>
commit 6032ebb54c60cae24329f6aba3ce0c1ca8ad6abe upstream.
The current code bails out with negative and positive returns.
If the callback returns a positive return code, 'ring_buffer__consume()'
and 'ring_buffer__poll()' will return a spurious number of records
consumed, but mostly important will continue the processing loop.
This patch makes positive returns from the callback a no-op.
Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support")
Signed-off-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20210325150115.138750-1-pctammela@xxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/lib/bpf/ringbuf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -227,7 +227,7 @@ static int ringbuf_process_ring(struct r
if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) {
sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ;
err = r->sample_cb(r->ctx, sample, len);
- if (err) {
+ if (err < 0) {
/* update consumer pos and bail out */
smp_store_release(r->consumer_pos,
cons_pos);
Patches currently in stable-queue which might be from pctammela@xxxxxxxxx are
queue-5.11/libbpf-fix-bail-out-from-ringbuf_process_ring-on-error.patch
