linux-kernel - [PATCH linux-next v2] perf/ring_buffer: Add EPOLLRDNORM flag for poll

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250314030036.2543180-1-chen.dylane@linux.dev>
Date: Fri, 14 Mar 2025 11:00:36 +0800
From: Tao Chen <chen.dylane@...ux.dev>
To: peterz@...radead.org,
	mingo@...hat.com,
	acme@...nel.org,
	namhyung@...nel.org,
	mark.rutland@....com,
	alexander.shishkin@...ux.intel.com,
	jolsa@...nel.org,
	irogers@...gle.com,
	adrian.hunter@...el.com,
	kan.liang@...ux.intel.com,
	fweisbec@...il.com
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Tao Chen <chen.dylane@...ux.dev>
Subject: [PATCH linux-next v2] perf/ring_buffer: Add EPOLLRDNORM flag for poll

The poll man page says POLLRDNORM is equivalent to POLLIN. For poll,
it seems that if user sets pollfd with POLLRDNORM in userspace, perf_poll
will not return until timeout even if perf_output_wakeup called, whereas POLLIN
returns.

Fixes: 76369139ceb9 ("perf: Split up buffer handling from core code")
Signed-off-by: Tao Chen <chen.dylane@...ux.dev>
---
 kernel/events/ring_buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Change list:
- v1 -> v2:
    - add changelog
- v1
  https://lore.kernel.org/all/20250313051047.2436098-1-chen.dylane@linux.dev

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 59a52b1a1..5130b119d 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -19,7 +19,7 @@
 
 static void perf_output_wakeup(struct perf_output_handle *handle)
 {
-	atomic_set(&handle->rb->poll, EPOLLIN);
+	atomic_set(&handle->rb->poll, EPOLLIN | EPOLLRDNORM);
 
 	handle->event->pending_wakeup = 1;
 
-- 
2.43.0