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 1101120E334; Mon, 23 Feb 2026 07:39:05 +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=1771832346; cv=none; b=Bobfpxrouf8mQZTLbSVEHIpIuOMYBm0aQQa6idkAIyrJ1c8R6BWlDy4IqB6TONaJ4go7JEZAcmCgqMG/8xWnntrJp0HssRW049ru1MJvJmwpFhh/Zt2c9kLXpr3ZRck/Hskvn1p+jNOTYvcgzHPThZ4ACgxsG/ew5jrDnSoUUfg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771832346; c=relaxed/simple; bh=xon9tZeAZO1aMXvaknMSEDPCNVUho772GHePKcQGCOM=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=NMMcIhEh5gDFV/2PoFTU8PblkUu1hoD7fCURk5AJuX2/pmw2q1UnVzzxjrH7ubot77yHFTT6NtOZ+8sKpcfdtR8qFrEdl1P2ekpKPZ334+Trl9ti9ZWSPKxrGzZz1aVLe1F8UhxYSlwQN1VZDf4LazglYYrWpf4FiPvV0gMdenY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HlTSnKRU; 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="HlTSnKRU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00639C116C6; Mon, 23 Feb 2026 07:39:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771832345; bh=xon9tZeAZO1aMXvaknMSEDPCNVUho772GHePKcQGCOM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HlTSnKRU666PMSdlcxON6nx/YPLyvi++6Csn+hg72b/uWdWyu8j4T1GdOUy0CuCxv D6tESCjpfPD6x6Pg0rTrlS7ZJVNysmNkWWCP/pE59aaWNDkBCOLPgeOAVNLPk4rwcC zLZrwGQUsyFV1n6zLUHxfafQK5zhU6SRu/r/kjvDAo0JZWdv9gH336Y0lm7oSzQUMx C/X95Pb/0+fBsYLxPBzRDvmfoGXHfspiOW7Zb5weQHBromSuyaYTn1mT9jdHIMLTk/ HX/umBYY/YiVozA7wH7hez4p/cJIaXl5RU3mDxlSnKgyUXRehxBd86i6tykWcNusxE hmtaPs3jJRy9g== Date: Mon, 23 Feb 2026 16:39:01 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v2 3/4] ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer Message-Id: <20260223163901.f37e03241282ac4f94d0f033@kernel.org> In-Reply-To: <20260220145656.7dd289f5@gandalf.local.home> References: <177140965047.1537493.15501794841217306382.stgit@mhiramat.tok.corp.google.com> <177140967567.1537493.7265236420134382381.stgit@mhiramat.tok.corp.google.com> <20260220145656.7dd289f5@gandalf.local.home> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 20 Feb 2026 14:56:56 -0500 Steven Rostedt wrote: > On Wed, 18 Feb 2026 19:14:35 +0900 > "Masami Hiramatsu (Google)" wrote: > > > From: Masami Hiramatsu (Google) > > > > Skip invalid sub-buffers when validating the persistent ring buffer > > instead of invalidate all ring buffers. > > instead of discarding the entire ring buffer. > > > > > > If the cache data in memory fails to be synchronized during a reboot, > > the persistent ring buffer may become partially corrupted, but other > > sub-buffers may still contain readable event data, allowing usersto > > recover data from the corrupted ring buffer. > > ... contain readable event data. Only discard the > subbuffers that are found to be corrupted. > > > > > Signed-off-by: Masami Hiramatsu (Google) > > --- > > kernel/trace/ring_buffer.c | 22 ++++++++++++---------- > > 1 file changed, 12 insertions(+), 10 deletions(-) > > > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > > index d2b69221a94c..0ae2a5ad8c3e 100644 > > --- a/kernel/trace/ring_buffer.c > > +++ b/kernel/trace/ring_buffer.c > > @@ -2045,17 +2045,19 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) > > if (ret < 0) { > > pr_info("Ring buffer meta [%d] invalid buffer page\n", > > cpu_buffer->cpu); > > - goto invalid; > > - } > > - > > - /* If the buffer has content, update pages_touched */ > > - if (ret) > > - local_inc(&cpu_buffer->pages_touched); > > - > > - entries += ret; > > - entry_bytes += local_read(&head_page->page->commit); > > - local_set(&cpu_buffer->head_page->entries, ret); > > + /* Instead of invalidate whole ring buffer, just clear this subbuffer. */ > > + local_set(&head_page->entries, 0); > > + local_set(&head_page->page->commit, 0); > > + /* TODO: commit an event to mark this is broken. */ > > Here's how to fix the TODO: > > local_set(&head_page->page->commit, RB_MISSED_EVENTS); Ah, that's a nice flag! Thanks! > > -- Steve > > > > + } else { > > + /* If the buffer has content, update pages_touched */ > > + if (ret) > > + local_inc(&cpu_buffer->pages_touched); > > > > + entries += ret; > > + entry_bytes += local_read(&head_page->page->commit); > > + local_set(&cpu_buffer->head_page->entries, ret); > > + } > > if (head_page == cpu_buffer->commit_page) > > break; > > } > > -- Masami Hiramatsu (Google)