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Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xPLxA-009NnJ-1J; Fri, 06 Nov 2026 15:34:08 +0000 Date: Fri, 6 Nov 2026 07:34:02 -0800 From: Breno Leitao To: Usama Arif Cc: Andrew Morton , baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, jbohac@suse.cz, david@kernel.org, hbathini@linux.ibm.com, kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kas@kernel.org, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, kernel-team@meta.com Subject: Re: [PATCH] crash: keep crashkernel CMA pages reserved if activation fails Message-ID: References: <20261104145600.3708886-1-usama.arif@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261104145600.3708886-1-usama.arif@linux.dev> X-Debian-User: leitao X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C8D60140005 X-Stat-Signature: q4rf8dddgg1ghywkujcneo5q63g6xmxn X-Rspam-User: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1793979260-783625 X-HE-Meta: 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 4K3HzaxV BZpb9S5Uw5YMd+4Xzpm4N7rwtm7lD4kq5B5M7u7gUumr5bAjvakk3lP5sgxh0yx1W+P49y1nlEw0gx5ngvHxHl6f2OHOvM2EUVTc0mmtQjm+t4J8/5WpRKiCgMf8Ta6Y5zNRphXYzJuz2UaEtOzsnJt6lho87/1M3yXMpXr5dYT1MZCCwHCdBCJTTd/nXkHot0MNO3y2xm3kJvPtB4QzXzLsnB6+v6VTLJ9CZoR9iMZEUZTFUep1g4k1SM6M5K5EncfvYvSfXlsZthiV2Imxzma2R/g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Nov 04, 2026 at 06:56:00AM -0800, 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 Tested-by: Breno Leitao