From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794218976; b=4OnK9T/2p0/iqc6R3yaat9UTFskrH0InVopn+Ix8ERkSTBrFAnD6koTNfNQGKvMJkqKf Y5ZrnsbeV3DDrRxDkE8HaKCdyICJqDpxhlXNM7kw6ZAlxkw214UV6b1XRSd0t4CA9QtRe rXJ5BRvESX1DhbypDHDWQhsmUwYNW+7g6u04k9mzli1wI5r8SoHoPORJc8xEO/l8fIrUM dDGfA5KC+PfxNEzP4qJCFcR6836bGT6/CYhToH/5wR1gUeYwA9xqlACmzSix4DdmkEUiJ 8T7aWcSH1ljwO2Kv5TnLdgM9n9YOwQP4yCPyfolbY8qyQ1q43X6H7L8SIZ4EY+ZGPcA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794218976; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=cVDZpxqqtGXanXSa85zXaSGNSgk4+pujulEU5rVUYrI=; b=veqMXMNZCpS4Ywa1Y2FRN+jPnD8RCjs2T+iduT+e1D9ARa/sT0G3NZcIOTm4rfJ4VGDV 9G+wI659VZibNyi5AjGxv+lzMdcgGtQoOttGUTJYBH2WmEfxKP9rFUsy4CgrRkHR06Gq2 7251KcRd+0hNxArXuzc9VhaIbsKzlYIweaZWBORBd+0PxC/rz11opf71kBtUiLlAUMRdK kQpu815hURABeOg4owrnLH/ykugKtwhM40/Y/aZgPm4+PXm6saXG+m/PjKuRvpNBioFdR G4oX3OygJFlwBcrFb/Ejhke9y0GQXH5p1uH2jfmOMvctkV5BSU7/GqGNhSNoSqwcRKA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RkD0ZTkK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8794606A326 for ; Mon, 9 Nov 2026 10:09:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RkD0ZTkK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52AA01F0089F; Mon, 9 Nov 2026 10:09:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794218976; bh=cVDZpxqqtGXanXSa85zXaSGNSgk4+pujulEU5rVUYrI=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=RkD0ZTkK4UPON4c35h81yShsugX7KG37JtcxD2aUF6JUC30zWJqFhbDGyKqUah9ae fP2maAVrCgbTCNnhOWJVTJhjX79zLJ/0RE7a7icltlw54oqi2yDeZ2WhBVR4ulKCT2 swE1tBlCR8QmzwQs3Tm3msHIU6pou/hNuz26EdKD3d+L0lrIbcRdJcLxUFT0dGV7A2 T4+0CI8h+D2boYeyH/j/gl6VVoSMgqf/fas9k5ObVWEF/08LvOecImOd6GEnB+Vvv9 TKnxk59d9A/Keuth0/lDlaE1ixFwS/OTMmkPcerP53RJx8DGnJL0EkgK2mC53fElRk 2xZZqsrVZFqkw== Date: Mon, 9 Nov 2026 12:09:29 +0200 From: Mike Rapoport To: Chris Down Cc: pasha.tatashin@soleen.com, pratyush@kernel.org, graf@amazon.com, kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] kho: Don't release incoming bootmem areas when kho_init() fails Message-ID: References: X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi, On Sat, Nov 07, 2026 at 07:40:50PM -0800, Chris Down wrote: > kho_populate() adds the incoming bootmem areas without reserving > them. memblock_free_all() then hands the remainder to the buddy > allocator. This paragraph is confusing. It reads like kho_populate() should have reserved bootmem areas, but it didn't. > Unfortunately however, if kho_init() fails, err_free_bootmem > currently frees every area with free_reserved_area(). This can free > pages still backing early allocations or free buddy pages a second > time. Is this an issue you hit in practice or it was reported by a code analysis? > To fix this, let's only free the areas on a cold boot when > kho_reserve_bootmem() reserved them. > > Fixes: c609c144b0e8 ("kexec: add KHO parsing support") > Cc: > Signed-off-by: Chris Down > --- > kernel/liveupdate/kexec_handover.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c > index 6f1f55fe3181..a566ad6634d8 100644 > --- a/kernel/liveupdate/kexec_handover.c > +++ b/kernel/liveupdate/kexec_handover.c > @@ -1899,11 +1899,13 @@ static __init int kho_init(void) > kho_radix_destroy_tree(tree); > err_free_bootmem: > kho_out.fdt = NULL; > - for (int i = 0; i < kho_bootmem_cnt; i++) { > - void *start = __va(kho_bootmem[i].addr); > - void *end = start + kho_bootmem[i].size; > + if (!fdt) { I think using !is_kho_boot() makes this clearer. > + for (int i = 0; i < kho_bootmem_cnt; i++) { > + void *start = __va(kho_bootmem[i].addr); > + void *end = start + kho_bootmem[i].size; > > - free_reserved_area(start, end, -1, ""); > + free_reserved_area(start, end, -1, ""); > + } > } > kho_enable = false; > return err; > > base-commit: fa4ad798f6f681031775266044ba1b0cf3c670bd > -- > 2.54.0 > -- Sincerely yours, Mike.