From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28D65473C9F; Fri, 7 Aug 2026 15:39:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786117144; cv=none; b=lOOL3DqVR8SF0J95QWoc6fDMCa/jeT0qgDTDlQNNKUFisTRBT5QwRWmj0Pbtu0PT1IBsB4ruVIXEDJKaZUlgb4YBmomouAGfKf8QvKDx8R/k6DobWIqjVextYAznn+uYzor5g20iO3bR4jK5AtLUo0mbTHyJJgP3/70GRk2Lia0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786117144; c=relaxed/simple; bh=gvcFFIkWg9CWIprxOfykdQwEUnY/h51XEUS1jb8JIaI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CRTUO7QDJC9tFBzCl/pJxppaZvaYX0x/Rkn5xg6yS9rK4apgKAb7t9lGVnew6yoN8L6GzwjRBOKjo7DwlRAkgpOwIQcFgJ7gWUt8SNdutARibv20zXuXfTtmdZMsXZxXcM2bCZNq7DBwu4Y+FhL9QDnKSz93SKkFIYA4zxO1bIc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AvlSBP8X; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AvlSBP8X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DEE71F00A3A; Fri, 7 Aug 2026 15:39:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786117143; bh=O0OR7nghDZLxKSgX61U9qIBr4PmoaEt7ef9QmjESgxc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AvlSBP8XqVLh47Q6Zt8Y8NkOoHXxHTQKGniRu1YGBWVnSFX9gpj9DC8iz7Ar2jwe/ NUD0O/tAAdHct6MNuzNdlRorSmuYzGNzabXpzqxgYBlINN9dWDoJJ+E9nEow8u9mOz /aDlCzWMGA79WrICaME/aofwZTBX4Hsqn/dfBa6M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vincent Donnefort , Keir Fraser , Steven Rostedt , Sasha Levin Subject: [PATCH 7.1 171/438] ring-buffer: Fix reader page read offset for remote buffers Date: Fri, 7 Aug 2026 16:36:07 +0200 Message-ID: <20260807143431.678040540@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143428.008222056@linuxfoundation.org> References: <20260807143428.008222056@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vincent Donnefort [ Upstream commit 78cd56c2a9d2e8da763cea3b06b636266ca66911 ] A page swapped in by __rb_get_reader_page_from_remote() retains its stale read offset, causing subsequent reads to skip events or read past valid data. Fix it. Link: https://patch.msgid.link/20260729133609.4022734-1-vdonnefort@google.com Fixes: fbd1743ecba1 ("ring-buffer: Add non-consuming read for ring-buffer remotes") Signed-off-by: Vincent Donnefort Reviewed-by: Keir Fraser Tested-by: Keir Fraser Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index da9339466bddd..d896fb25de702 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -5624,6 +5624,7 @@ __rb_get_reader_page_from_remote(struct ring_buffer_per_cpu *cpu_buffer) cpu_buffer->head_page = new_head; cpu_buffer->reader_page = new_reader; + cpu_buffer->reader_page->read = 0; cpu_buffer->pages = &new_head->list; cpu_buffer->read_stamp = new_reader->page->time_stamp; cpu_buffer->lost_events = cpu_buffer->meta_page->reader.lost_events; -- 2.53.0