From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) (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 09D7B280A29; Fri, 30 Jan 2026 00:33:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769733238; cv=none; b=TbLu/xBkIFcyVfwJ8AP107MNQHreopTfxqx3EzUW5MBGFgK2Y0qWcgZTD0KNKjL171tV8aL6ZT8KTg0MLQXK7StnCoUw+EuSChSser1QmdIY/22J/+fZDhefLG3D4cY7UIEBZHpLJ/Wv/VR6R0gRi67KGl08z6HdIllM10oHxq0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769733238; c=relaxed/simple; bh=d6IMeyNM4unHSukipAFZgIfHBD3mlNa9hzhm/Sgtiz0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Lv6Lj1IhwBsiucqhKPATtt+Ftrm2gc0GGCVdO3HNlvMNVCQdhZAtr08fXVbsURLNWhfHIY3Ll0Cw94Sz7Z4jQDkBddx/TqcgYSvpvd9yavX/XirG9omMFP1qpzMK9gq0eQvktqAyGngwgsAjQk1t0jAoyQUzmHkmvtGRFxgXCww= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 06F52C17B8; Fri, 30 Jan 2026 00:33:48 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf09.hostedemail.com (Postfix) with ESMTPA id DA42720028; Fri, 30 Jan 2026 00:33:46 +0000 (UTC) Date: Thu, 29 Jan 2026 19:33:59 -0500 From: Steven Rostedt To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Sebastian Andrzej Siewior , Alexei Starovoitov Subject: Re: [PATCH v6 0/3] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast Message-ID: <20260129193359.08230ac0@gandalf.local.home> In-Reply-To: <581f0711-9115-44e8-a616-06cd13563f8c@paulmck-laptop> References: <20260126231145.728172709@kernel.org> <20260126213922.0a91bfac@robin> <581f0711-9115-44e8-a616-06cd13563f8c@paulmck-laptop> X-Mailer: Claws Mail 3.20.0git84 (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 X-Stat-Signature: 7kqirdwd8d89xo84hp4c5wzx6wzwro91 X-Rspamd-Server: rspamout02 X-Rspamd-Queue-Id: DA42720028 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+FsuGFyUUlC2dJYOoKWqKPfYMAAxZKTqM= X-HE-Tag: 1769733226-202996 X-HE-Meta: U2FsdGVkX1/VqSkVw2yT/Pyuj+9KTmxqYLJwn/LMBdsPU+U4+g2+xJ+cdBU0by0A18XTqUjxyiwl1y8rx2b98K8+1HOKhRKtlKX9/N1KuL/Xy3Bit1z8CYSWpzLQslaoE+mgisznbGFE6/VWjuXgIfk3G1nNiuwlvawAdHVeIBIxtw8s7L2ytuuAi7W/YWQJaVngylLuivA41PeU7bN3V95X6zN0OIWPNht1294aEgaRlM4ig+ENiDUC+5oyXy4N+PCU1EfFMYloHBGyLHUmMuAaB618DLQR+q2osf8c07C9hfjRb3PDMyVWkYbDYfhVZdkSUduwAGuAVUWCanEKYwa9ObOPA6xUFNR3CYvuuv9ZxJety0ouSS95OJB6Aade1kUdy6LkXZnrtVNXhv4N6Q== On Tue, 27 Jan 2026 15:18:05 -0800 "Paul E. McKenney" wrote: > Ah, I get it. I think. NMIs, right? > > In your source tree, line 792 of kernel/rcu/srcutree.c is this line of > code, correct? > > WARN_ON_ONCE((read_flavor != SRCU_READ_FLAVOR_NMI) && in_nmi()); > > If so, could you please try this test with the patch shown at the end > of this email? > > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index c469c708fdd6a..66ba6a2f83d3a 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -789,7 +789,8 @@ void __srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor) > struct srcu_data *sdp; > > /* NMI-unsafe use in NMI is a bad sign, as is multi-bit read_flavor values. */ > - WARN_ON_ONCE((read_flavor != SRCU_READ_FLAVOR_NMI) && in_nmi()); > + WARN_ON_ONCE(read_flavor != SRCU_READ_FLAVOR_NMI && > + read_flavor != SRCU_READ_FLAVOR_FAST && in_nmi()); > WARN_ON_ONCE(read_flavor & (read_flavor - 1)); > > sdp = raw_cpu_ptr(ssp->sda); It appears to fix the issue. Tested-by: Steven Rostedt (Google) Care to send a formal patch, and I'll add it before the patch that causes issues. Thanks, -- Steve