From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yx1-f46.google.com (mail-yx1-f46.google.com [74.125.224.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5ECC7366806 for ; Wed, 6 May 2026 15:12:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778080350; cv=none; b=nfJ1PFn6vGlmR+zDMgHa2MKI3HC3Y5CSwUWux1Bsae1VOUJcdh8oix4YxdWdj8IaGCGQZxkty37lJoDpLpFem4NZMyObVuDQrUkGDnm57nBUxE3Z8+Ywc6zQypUs1A3CTGPG486t9KyEMG+uhJwaIXsdB9KCGtaqmZV6ltfwOBw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778080350; c=relaxed/simple; bh=+lxghuMS2F10wTtbYZBJmFhOnaYRcRlPjC5kAzDpVbs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MpRkt63Gctzk4Be/ZNPArN/zVwY6uAOZibU6X4CYk1rWGdyQ13m/5SUi1SUupz3gzQKjARdKtPjpwrR/PST65+27OJYipy4C+8OMi6FNCgrluM3lwEDti8lRuXnuAn7KlJuy9zK6kFLXvlYa3alt+Q4HyqaA51YRfAn8bsAWgGs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b=jHtrtK7A; arc=none smtp.client-ip=74.125.224.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=soleen.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b="jHtrtK7A" Received: by mail-yx1-f46.google.com with SMTP id 956f58d0204a3-651d692e833so6997570d50.3 for ; Wed, 06 May 2026 08:12:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1778080348; x=1778685148; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Su2p72OGhTa6hvAv10iYjEdJ5nUmIFzciV3ESYU7Ql4=; b=jHtrtK7A/lya2PE3FOkpSnE4/DirPiebKbsQjl5/tIFld8WAMPiR6xHgOXLly3Bec9 Ls8/1oMPyz/Jv2MbESR19ZAHC0RV4D9gI6ZluQ4Vujfp9+e4jYRUoyJCrTWqDVvqjkV+ OSfA+bmWFxL6SPyuioF3WRYBzjC9flwa15I/HHROKcTg8i34QNLCpfA8nkIbsFeLaXR5 l6WsPefekPRMAijcIHqX13x9bWdhd6QlhBcas2+uqFGVrizIp8JlbkfB3R7LrNIQgtu2 lOEf4YyFAfTQHA5TDbOUYO+qHQbWJ/HuqDE0Ti52/90S9WET+DcVF3Toa70Pa8Tj7+Kc R5+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778080348; x=1778685148; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Su2p72OGhTa6hvAv10iYjEdJ5nUmIFzciV3ESYU7Ql4=; b=ctN57GbVgGCHhb06W1m3Z1zq9c1BJ5saatX+7ca2Za/HAtTH8nicYEMGWkpqcPIIpM lJVE+tWHxlAdMyG5hfQc/bsEiyjbyc0EFeNSym0wZ/kLLrWJeGQdGH/W5gnWWSYCEXzo dOuZus90beUyZUCQz/4eM+84HUG1OexrYg777rpxpBJQ0jgpIqXGKJhrAI2ax1vP76os s5h4tllrSxnhQlpdC469qn4nTrKE+K/uVEU7r+AxWgikrz5wFqeXMZ3Mb2DgiXgcZonL mudW38r15GEceLF5RQfx7zj1G4EtKyPgTNg0GPub72hmv3fK3CFe0EvuTr/U6EsQQk2J B76w== X-Forwarded-Encrypted: i=1; AFNElJ/oNTmIl3BCOTlg035UhAonRwvcyLWltiP6N2pffk+OsMXcPTnV4q2Zoe9OpGWZreBuP4WtH/bkL0oxPkw=@vger.kernel.org X-Gm-Message-State: AOJu0YyZSFE07Lvf5WU2JhYsRtPVez6AMszQWZwpOUWS0ewafvQXoRLp 6vNKraKZhCEbxuYAdqV6E0CyWmyAzU111AxHtOjRPj+b4dWQb+xgolAB1dhaq0xbwr8= X-Gm-Gg: AeBDies9DYyr5vqsOwjd5+1JGl10g/zsIDjNvqvfk0VYiREF5W8Y9CgTsAkzlhp3jCj AkEN4TZ5aG2iV7M0NTZIeyf/t4tWK50HYsaoopIf1qooewSfvTnHVWDH3E+R+ipxexkR+zIO0Rl CeuvexVjrrJ4xlf48XfD/9ekPEhn1N4HPAnS8XTUu8tMblI+0JFoyYM9qZ6x8CT7GlJd8EtN12i aT7R33QUUcmgTy9ieuVHoov1/k94pfxdyeRJkGI6hny9BCGgiUTP9Es2tIIt8MKsUuYy0TMyOgK dpcboCeqncywOtORZdQPTqoxILvtQzh0n/kEYsbG3hffyQSrwSaEadRpX74gnxETfVL+XFwqMuy P7iSAmRSmpcaoHHiUfd0Pu6k1A4WXYMqyba4/+c5tn/06OKEps9r/8DH7rTuRfOF88sEqvAHrKm hf/rbdP5ypGE9DE63EOAKtZKMTFI6MOqvJTQSfWYgUznqnfgV079KzTDI+l4lHWRAq90aJyWzwH 0bdg6luZJhLzRCja2A9RzltJIVAhZq4SYxZQN+BTFxzO1btGVk= X-Received: by 2002:a05:690e:2497:b0:651:a928:4c90 with SMTP id 956f58d0204a3-65c799d8571mr3470884d50.43.1778080348335; Wed, 06 May 2026 08:12:28 -0700 (PDT) Received: from google.com (57.233.150.34.bc.googleusercontent.com. [34.150.233.57]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-65c7afc6b18sm1171087d50.14.2026.05.06.08.12.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 May 2026 08:12:27 -0700 (PDT) Date: Wed, 6 May 2026 11:12:26 -0400 From: Pasha Tatashin To: Pratyush Yadav Cc: Pasha Tatashin , rppt@kernel.org, sourabhjain@linux.ibm.com, jbouron@amazon.com, akpm@linux-foundation.org, bhe@redhat.com, linux-kernel@vger.kernel.org, dan.carpenter@linaro.org, liaoyuanhong@vivo.com, rafael.j.wysocki@intel.com, piliu@redhat.com, kexec@lists.infradead.org, graf@amazon.com, mario.limonciello@amd.com Subject: Re: [PATCH v1 1/3] liveupdate: skip serialization for context-preserving kexec Message-ID: References: <20260506043200.2025677-5-pasha.tatashin@soleen.com> <20260506043200.2025677-6-pasha.tatashin@soleen.com> <2vxz34050wi7.fsf@kernel.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <2vxz34050wi7.fsf@kernel.org> On 05-06 10:31, Pratyush Yadav wrote: > Hi Pasha, > > On Wed, May 06 2026, Pasha Tatashin wrote: > > > A preserve_context kexec returns to the current kernel, which > > is unrelated to live update where the state is passed to the next > > kernel. Skip liveupdate_reboot() in this case to avoid serialization > > and prevent sessions from being left in a frozen state upon return. > > Should we also stop KHO? Now it is stateless and always finalized. I am No. KHO preserves kernel internal memory; for context-preserved kexec, the 2nd kernel and the 1st kernel do not have overlapping memory. So, whatever the 1st kernel maintains in KHO is an internal detail of the 1st kernel. Once we return from the 2nd kernel to the 1st kernel, all KHO memory is going to stay as-is, and the 1st kernel can even perform a regular kexec or live update later. Pasha > not sure how these kexec jump images will interact with KHO data, but > seems like we shouldn't be handing over memory if the image will jump > back. > > Anyway, for this patch: > > Reviewed-by: Pratyush Yadav (Google) > > > > > Fixes: db8bed8082dc ("kexec: call liveupdate_reboot() before kexec") > > Reported-by: Oskar Gerlicz Kowalczuk > > Signed-off-by: Pasha Tatashin > [...] > > -- > Regards, > Pratyush Yadav