From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=5.75.144.95 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793819846; b=P8oQjbKHiUBhOKht9XVqpolQemhHHfETuT/AqfXml5s9Uet6n8Gl4X5yD2t1iEkHKUS8 BPhV7vgLKlJwjlf+t9mnzwhN+bHte1QLL6417E9vuxXBldlywTI9R/GAYlGOzbKBBHPIa 3dClz1wqGdM4XnLfNzMvqGmKny2W3pO5WEjvOJXNiOfUPKeoLrjx/sQOYD2CHVt2KOCKO t8a/9J1YLXKcKppaPnOb/OkY1rw9JWzN305ZVpzMdBkqIBXB9TlRmU5eHi4L6nb1fKeMn LrrMzBTRL37Yt07Xn6Okhvyi47fkGERwXmd7sE0MrWr3GItGR4Zh1er0QbCI+VQ+4Bw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793819846; h=DMARC-Filter:DKIM-Signature:DKIM-Signature:Date:From:To:CC:Subject: In-Reply-To:Message-ID:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=q9RBWwFn63CofyiYGd/4lZu+7oEXCckEZxKnFr8wcCE=; b=Xhuj90e0GV3Y/Equzcdpn49N/Xbq2DzKP0hV8AjimhauHKDJwKgAFlcp0ug6fXeEpr9F sshd87enOHCr//hr1H/FtQPInuLfPrh/mBnLDSd5s8kiBrTY/Pa2wyKioH8wH25iS2cF1 5P4aFBqrXqXy9RJqZz1UV9q7NiSk24uAFaqPtDfyle7HRn5SC3BYaNpClYs5EyF5KR3Ro aKCdEK+K/bGsiKgvDGFnQkakIT1I7W4foZ33yU6Aq/Ev2koqpsMcxj5aIcm4h9YTJjVbF QcHEaESIEInGitYTr4Tci/ROBYyor6K81FE0lOF0DtaRJarCZGbNKC8opPKQBfGIdaw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=mainlining.org; spf=pass smtp.mailfrom=mainlining.org; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=rsa-sha256 header.s=202507r header.b=gzTXmkeW; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=ed25519-sha256 header.s=202507e header.b=vj1HCCKS; arc=none smtp.remote-ip=5.75.144.95 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (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 51079608362D for ; Wed, 4 Nov 2026 19:17:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 51079608362D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mainlining.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=mainlining.org header.i=@mainlining.org header.a=rsa-sha256 header.s=202507r header.b=gzTXmkeW; dkim=pass header.d=mainlining.org header.i=@mainlining.org header.a=ed25519-sha256 header.s=202507e header.b=vj1HCCKS DKIM-Signature: v=1; a=rsa-sha256; s=202507r; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Subject:To:From:Date; t=1793819801; bh=q9RBWwFn63CofyiYGd/4lZu +7oEXCckEZxKnFr8wcCE=; b=gzTXmkeWedj7jRMbeoQJEsmjhBNYW0Lz0whmZZ73mqb7xJZGUK Pe3GeqEi0YHA8IMGoQjJ6VQ9UKvEL4/euRcCjSWuqeS/jTZ7JIhiFfebuUdX9Un2iagtAm68SZt g7ZhuBIynlrhXulbo9J3JRKsx9wxWsYU2x2BPzgdTE7MCCK6YCDWhgQ920TUXS6NRsOiNvdButH WgYg8ppX9lCVITHtxFrJ1HqUx3Dpy4To8lAiVPJ3qLIb++DPgaNIj2jhB8RUpLAl2tl2RpRTkbK 8rDrIqoPH2r4wAGVZ7MjTghGFhAfoGgFd9BVRTBklEbCN2TikRBZ6m/m/dTgkHFODqA==; DKIM-Signature: v=1; a=ed25519-sha256; s=202507e; d=mainlining.org; c=relaxed/relaxed; h=Message-ID:Subject:To:From:Date; t=1793819801; bh=q9RBWwFn63CofyiYGd/4lZu +7oEXCckEZxKnFr8wcCE=; b=vj1HCCKSlnZcl02DJs+dAIAwPBQk/jfbwXDewIbV+HhF7idwxm 6+RapBxR5/PdGjgGbwAAC8XvAfJkeOLtMbBA==; Date: Wed, 04 Nov 2026 19:16:42 +0000 From: Bradley Morgan To: usama.arif@linux.dev CC: akpm@linux-foundation.org, baoquan.he@linux.dev, david@kernel.org, hannes@cmpxchg.org, hbathini@linux.ibm.com, jbohac@suse.cz, kas@kernel.org, kernel-team@meta.com, kexec@lists.infradead.org, leitao@debian.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pasha.tatashin@soleen.com, pratyush@kernel.org, riel@surriel.com, rppt@kernel.org, ruirui.yang@linux.dev, shakeel.butt@linux.dev Subject: =?US-ASCII?Q?Re=3A_=5BPATCH=5D_crash=3A_keep_crashkernel_C?= =?US-ASCII?Q?MA_pages_reserved_if_activation_fails?= In-Reply-To: <20261104145600.3708886-1-usama.arif@linux.dev> Message-ID: <661AFDEC-B8DF-4A5B-8C58-1D39F518F068@mainlining.org> 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=utf-8 Content-Transfer-Encoding: 8bit On 4 November 2026 14:56:00 GMT, Usama Arif wrote: >reserve_crashkernel_cma() adds each crashkernel CMA area to >crashk_cma_ranges[] as soon as it is declared. If the area later fails >activation, e.g. because movablecore= put the ZONE_MOVABLE boundary >inside it, cma_activate_area() releases the pages to the buddy allocator >as ordinary memory. The range is still handed to the crash kernel and >excluded from the vmcore, so kernel data that lands there is overwritten >by the crash kernel and missing from the dump. > >Mark the areas with cma_reserve_pages_on_error(), so that a failed >activation leaves the pages reserved: lost to the first kernel, but safe >for the crash kernel to use. > >Fixes: ab475510e042 ("kdump: implement reserve_crashkernel_cma") >Signed-off-by: Usama Arif >--- > kernel/crash_reserve.c | 1 + > 1 file changed, 1 insertion(+) > >diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c >index a03f0a4305a4e..a4b616ed49482 100644 >--- a/kernel/crash_reserve.c >+++ b/kernel/crash_reserve.c >@@ -498,6 +498,7 @@ void __init reserve_crashkernel_cma(unsigned long long cma_size) > continue; > } > >+ cma_reserve_pages_on_error(res); You do know that this will activate under every bitmap_zalloc() failure, right? Is that accounted for? > crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res); > crashk_cma_ranges[crashk_cma_cnt].end = > crashk_cma_ranges[crashk_cma_cnt].start + > --- Thanks!