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 84DEFBA27; Fri, 18 Jul 2025 10:27:18 +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=1752834438; cv=none; b=TuWrMAg3zYReAxUtB0hFnWgrz0wcslUcUOTLcTWLU9Gy/FC5OpartMiGf2f9IgkC9h7gkjSzC13o8ftB5E6zDeYwav2K0J3harvZ7GbIpGUkGYJJ64FBt06EUbhwb0Pql29Rn597OTPPE+fp/ATbE7n7j2zmWhTy0XWAcSgX0wI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752834438; c=relaxed/simple; bh=RSLPZfhWxQYnSXaCJXfPgeIgZNT7vJZLbF48MWYtaNU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MTHPS0Oq8e+mHDLuuAzQ11N+WLTyi5N5dMZBYBtbh6AmGNBtiiuZOIlbRUR22ic0+Po341TJ2EKtz4H4xiunMFOQiB9wCNhGyYedkaCYkPDyXW2uXYShEFg1FTT87FEkxsoRNAgjCP9CscQRFZRyRTe1PVpPrQm70s9v2Vx+CmA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LDTUrCz5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LDTUrCz5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAE4FC4CEEB; Fri, 18 Jul 2025 10:27:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752834438; bh=RSLPZfhWxQYnSXaCJXfPgeIgZNT7vJZLbF48MWYtaNU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LDTUrCz5NxGOn4y5Ve3I/7yNBxscqW5Lgjiypa0IeUjDjyXq14HMmTry8p3Auu5E7 ZMeX0Lt/jCbdrN28fAj5RQcU+Ntwcku1HpPblnXgC8gC/wvGK6WjkwVc5Ljbx84+iv icW4Wr9FHXSEneCTD86/B69kZT4Zne8q03jdyu3g= Date: Fri, 18 Jul 2025 12:27:14 +0200 From: Greg KH To: Nam Cao Cc: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Gabriele Monaco , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] rv: Ensure containers are registered first Message-ID: <2025071835-enjoying-darn-f5d8@gregkh> References: <20250718091850.2057864-1-namcao@linutronix.de> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250718091850.2057864-1-namcao@linutronix.de> On Fri, Jul 18, 2025 at 11:18:50AM +0200, Nam Cao wrote: > If rv_register_monitor() is called with a non-NULL parent pointer (i.e. by > monitors inside a container), it is expected that the parent (a.k.a > container) is already registered. > > The containers seem to always be registered first. I suspect because of the > order in Makefile. But nothing guarantees this. Yes, linking order matters, and it does guarantee this. We rely on linking order in the kernel in many places. > If this registering order is changed, "strange" things happen. For example, > if the container is registered last, rv_is_container_monitor() incorrectly > says this is NOT a container. .enable() is then called, which is NULL for > container, thus we have a NULL pointer deref crash. > > Guarantee that containers are registered first. > > Fixes: cb85c660fcd4 ("rv: Add option for nested monitors and include sched") > Signed-off-by: Nam Cao > Cc: stable@vger.kernel.org > --- > include/linux/rv.h | 5 +++++ > kernel/trace/rv/monitors/pagefault/pagefault.c | 4 ++-- > kernel/trace/rv/monitors/rtapp/rtapp.c | 4 ++-- > kernel/trace/rv/monitors/sched/sched.c | 4 ++-- > kernel/trace/rv/monitors/sco/sco.c | 4 ++-- > kernel/trace/rv/monitors/scpd/scpd.c | 4 ++-- > kernel/trace/rv/monitors/sleep/sleep.c | 4 ++-- > kernel/trace/rv/monitors/sncid/sncid.c | 4 ++-- > kernel/trace/rv/monitors/snep/snep.c | 4 ++-- > kernel/trace/rv/monitors/snroc/snroc.c | 4 ++-- > kernel/trace/rv/monitors/tss/tss.c | 4 ++-- > kernel/trace/rv/monitors/wip/wip.c | 4 ++-- > kernel/trace/rv/monitors/wwnr/wwnr.c | 4 ++-- > tools/verification/rvgen/rvgen/templates/container/main.c | 4 ++-- > tools/verification/rvgen/rvgen/templates/dot2k/main.c | 4 ++-- > tools/verification/rvgen/rvgen/templates/ltl2k/main.c | 4 ++-- > 16 files changed, 35 insertions(+), 30 deletions(-) As there is no bug now, why is this a cc: stable patch? thanks, greg k-h