From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7C52D38B7D4; Tue, 25 Aug 2026 05:21:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787635293; cv=none; b=s42cyuhilsoZDz8qSWKjMt5CeikKPAI8dnGSlkRnI92SfNoeQeJ7gNoLaCUbk52Xy+kr7KNEbgVuc1ZiygtFG5ED7ziJ+O8W9CLaG0dYlLOqlX0ltttlV4W0Rsfgq1OF8G5SVbfp3516c0QXdWLahM1V/CxG9oiyADVEPEQW7JI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787635293; c=relaxed/simple; bh=x74r0oqsaq9tYSELP0l1x9/SUc0crA2uxMOnhcHAnpA=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=biq+PQ3S3i4RVh8oFwGeleGfJulbGHCdQBfjJXlQ8jtHrGZJR21jg24Q4lHMU7Of4oAfAWUta6hShIrNqgAoRJBvRgJKCy8XO3hbhVFfuOSEynkSafOY5x/+kk9cPZImuaB3j1VdqvlRK40LhdC+IFNqGL6dCsaQuO7SKZaCVuo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rtQ6WjJ8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rtQ6WjJ8" Received: by smtp.kernel.org (Postfix) with ESMTPS id 1EE4EC2BCB8; Tue, 25 Aug 2026 05:21:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1787635293; bh=x74r0oqsaq9tYSELP0l1x9/SUc0crA2uxMOnhcHAnpA=; h=From:Subject:Date:To:Cc:Reply-To:From; b=rtQ6WjJ8jx9oM1ZY1uPYNfVnfh8bzl6NAYepIun0iheRKDvQHcKzT7L8xvtX53se8 86Zm1uaTQtvn7YwelAnxI//45j9ShVVFsNKq2A3/dYeHKQxfPe+hflPOntxJkcRNYC ZnX9d7lOJqC0FFfrltJyh6CfXEdjdRHejMVqgzHLOMNS3MjrzPjcJAW3nsSxk7/HzV re+fENhpvslO6M+ajp/wb0oAFJsheuTLYviYtJ/9HTeXVBqLg4HsOk7FVuybkInIHE 3OkoWJwayJiJuOZ/1JM4nULIZFkxwKPx55plzL4DqQ4e9J8kfoRouJdY3t6qkG8wf4 DRZy9I8jFsbiQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AEA0C5DF9C; Tue, 25 Aug 2026 05:21:33 +0000 (UTC) From: Ivan Immanuel Shaji via B4 Relay Subject: [PATCH 0/2] tracing: Fix remote reader page swap failures Date: Tue, 25 Aug 2026 01:20:36 -0400 Message-Id: <20260825-kernel-patch-1-v1-0-e9349aa0b165@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/x3MQQqAIBBG4avErBtQI4muEi0k/2ooLDQikO6et PwW72VKiIJEfZUp4pYkRyjQdUXT6sICFl9MRhmrOtPyhhiw8+muaWXNvlMWjYfSrqUSnRGzPP9 wGN/3AxXYl1VgAAAA X-Change-ID: 20260825-kernel-patch-1-d806e3de01a5 To: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Vincent Donnefort Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, stable@vger.kernel.org, Ivan Immanuel Shaji X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787635292; l=1366; i=ivanimmanuel1234@gmail.com; s=20260825; h=from:subject:message-id; bh=x74r0oqsaq9tYSELP0l1x9/SUc0crA2uxMOnhcHAnpA=; b=ObxVAA6UI2ihrhJIU4/e9qvfLbnlcNFTBkhdrffzuyuU9mZ1EYkMCnplYc4UGI0p/FmqxQ8Rd jHQhX13kHVSDZda8WvuCSamRddJzrRXoxqKqSKhZRjixHXrI/RyE5yT X-Developer-Key: i=ivanimmanuel1234@gmail.com; a=ed25519; pk=Wx8O3UUs3XneDkbqbOJJnlNdWSpEf2tWbTAoE7/vnqE= X-Endpoint-Received: by B4 Relay for ivanimmanuel1234@gmail.com/20260825 with auth_id=975 X-Original-From: Ivan Immanuel Shaji Reply-To: ivanimmanuel1234@gmail.com The simple ring buffer's reader-page swap retry loop mishandles its last attempt. A success at that point is reported as an error, while a failure is allowed to continue into the pointer updates. The remote ring buffer consumer compounds callback failures by warning and continuing with stale reader metadata. Fix the retry result in the provider, then stop the remote consumer before it mutates its local page list when the swap fails. These paths are used by remote tracing, including arm64 nVHE EL2 tracing and CONFIG_TRACE_REMOTE_TEST. Testing: make C=2 W=1 kernel/trace/simple_ring_buffer.o kernel/trace/ring_buffer.o scripts/checkpatch.pl --no-tree (each formatted patch) No runtime reproducer was run. The two final-attempt outcomes follow from the retry counter's post-decrement semantics. An arm64 cross-compiler was not available. --- Ivan Immanuel Shaji (2): tracing: Fix retry exhaustion in simple ring buffer reader swap ring-buffer: Stop remote reader update when page swap fails kernel/trace/ring_buffer.c | 5 +++-- kernel/trace/simple_ring_buffer.c | 4 ++-- 2 files changed, 5 insertions(+), 4 deletions(-) --- base-commit: 66498c75b4f8017f62d720d9b59675bdf3abce91 change-id: 20260825-kernel-patch-1-d806e3de01a5 Best regards, -- Ivan Immanuel Shaji