From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 1D745372050 for ; Thu, 30 Jul 2026 02:40:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785379241; cv=none; b=LQbaXnv3HXSl71Nj1wWvbeAIYozK3SRUM5dqNWOA3DghapKaKAQyGWlsPARYRI7j4ZsGYL6IcnMX1lKRNuF3DRkJAPcwc2TuN/lgrl7tCt7XXmhGeemEJWpO/5OhldGiym0JAGKtSmFxnsUpJPmKtrr/yRVYhFvh6l+ys4m/cPU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785379241; c=relaxed/simple; bh=6G4Xma+nHyY7H4SK8n91Do8E6lFjpiFxFrum0hOvvVo=; h=Mime-Version:Content-Type:Date:Message-Id:To:Cc:Subject:From: References:In-Reply-To; b=k/yprW4QUX830pP6iqDwlkmILUCeKR5FhPlKu1+nKUed5cZDKE5WN7xXSGOvbaUYa+ixXik0u5KBNBEd+v2H1LDSD166PmUqFqOXks28se+E3FZOBY6pxksm3kXcp7FFjU6M17oAbrwFdR75YAtk6yz2MncxMqhevRdYWbSkw0E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=VAV1Wozj; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="VAV1Wozj" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785379227; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5B2ge7eLjQjPjb19+CHal8Uxkv+UmEOOCeLjm8fv4Ac=; b=VAV1Wozjjbctt9UIbsrw6lWTDArWr2lROWoB6yGPbEY3OAPKi7jY3Hm4QDpoj0ezssOa9b x8y4w5g4hv4fGXvuuY7dIe1+gRNg9C+PePCodCFtDN4YtlA2D9SPeQFhy1LF1jOP5/7H5H y4Gf2OblrZcF+GSyPNTIt5j11WHC2SU= Content-Type: multipart/signed; boundary=554137b98fdb9fb3d0fba56055422f9db991cf28966e80a0180e40cc316f; micalg=pgp-sha512; protocol="application/pgp-signature" Date: Wed, 29 Jul 2026 19:40:19 -0700 Message-Id: To: "Troy Mitchell" , "Paul Walmsley" , "Palmer Dabbelt" , "Albert Ou" , "Alexandre Ghiti" Cc: , , , "Troy Mitchell" , "Aurelien Jarno" Subject: Re: [PATCH v3] riscv: disable local interrupts and stop other CPUs before reboot/shutdown X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Troy Mitchell" References: <20260330-v7-0-rc1-rv-dis-int-before-restart-v3-1-5a0577fcd136@linux.spacemit.com> In-Reply-To: <20260330-v7-0-rc1-rv-dis-int-before-restart-v3-1-5a0577fcd136@linux.spacemit.com> X-Migadu-Flow: FLOW_OUT --554137b98fdb9fb3d0fba56055422f9db991cf28966e80a0180e40cc316f Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 On Mon Mar 30, 2026 at 2:58 AM PDT, Troy Mitchell wrote: > From: Troy Mitchell > > Currently, the RISC-V implementation of machine_restart(), machine_halt()= , > and machine_power_off() invokes the kernel teardown chains (e.g., > do_kernel_restart()) with local interrupts enabled and other CPUs still > running. > > This implementation fails to provide a deterministic execution environmen= t > for registered handlers in the restart or power-off notifier chains. Thes= e > chains are intended to be executed in a strict atomic and single-threaded > context. > > Specifically, under CONFIG_PREEMPT_RCU, rcu_read_lock() does not incremen= t > the preempt_count. If local interrupts remain enabled, the environment > is not guaranteed to be atomic. This can lead to a context misidentificat= ion > within generic kernel teardown code, causing it to incorrectly enter > non-atomic paths (such as attempting to acquire sleeping locks), which > results in fatal "scheduling while atomic" splats or system hangs. > > Additionally, stopping other CPUs ensures the primary CPU has exclusive > access to the hardware state during the final teardown phase, preventing > unpredictable interference from other active cores. > > Align RISC-V with other major architectures by disabling local interrupts > and stopping other CPUs at the beginning of the shutdown sequences. This > guarantees the architectural expectations of the kernel's restart and > power-off handlers are met. > > Signed-off-by: Troy Mitchell > Tested-by: Aurelien Jarno Hi Paul, A gentle ping on this patch. When you have a chance, could you please take a look and let me know whether this approach looks reasonable? - Troy --554137b98fdb9fb3d0fba56055422f9db991cf28966e80a0180e40cc316f Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJcEABYKAD8WIQSL4Ay2cExaPXAQcU2YCe+A+TM0LwUCamq5kyEcdHJveS5taXRj aGVsbEBsaW51eC5zcGFjZW1pdC5jb20ACgkQmAnvgPkzNC/WUAEAo/Ayg3TKHBDa h9ruUla/m+yRTaS8PyNF80vaN+vWPBsA/3qm/T+HOqlqDGPdwk5MY23wPc7amVyX g6ursIB/U4kO =1YnG -----END PGP SIGNATURE----- --554137b98fdb9fb3d0fba56055422f9db991cf28966e80a0180e40cc316f--