From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 442F54A1E0D for ; Wed, 9 Sep 2026 09:58:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788947907; cv=none; b=jQJ6R/aMpq2aGH1sQbWzk7+CgGaKZdC8ewM5AF6Q4tnoQwmXBgY6GEnhfrTjazLIjUbA06v361t7znDNwHQkbhf29fPGjNNF3V4gP1QMdS1EgZjE9z2AgB5oQryQ6aA0fkeA04be6pWMdPQTqip6M6HYYlD/PW3bOimCaXVs5js= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788947907; c=relaxed/simple; bh=/QJhheoWSo+RsLQ0RSKHnxeSKvHMSvuCFYfUpQM6CQ4=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=TXwIyb9ARa1swzd/Jnz+x7tj5dL+qgbRqqQ5HFV9gUFFuV6hCz9NTa5clQrrPFizNFEmUoFWZ+vYc90/rO8WyvCydqfvIeS9rco2XLDhbw/gyCMg834wfYZnwD7u63TW1sn/koJzIZgPgF+dCglaF/yLtSU2XDgiy1ijA6/3eMg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qtZZ5DIk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qtZZ5DIk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13E711F00A3F; Wed, 9 Sep 2026 09:58:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788947900; bh=NlSfbi4b/vEV26RB6yJ4xzZIqHO6YcNujjBWxfO0KzE=; h=Subject:To:Cc:From:Date; b=qtZZ5DIkGbKqTgCsMRqHoMav5rA/IQEF9BfsUxoObckvFP9tDv2vaCCxycjiQOSOg j9E4COONPmxCc88wlClTpvOBD3mFyeUDJhb+tn9uPpXXH2kRXn9BScdYZJm7VjSg0S G5vU5PEy6Ym1cJOPN94EL5WwCyvUuCoRlOyhBDR0= Subject: FAILED: patch "[PATCH] powerpc/kexec_file: Prevent kexec range truncation" failed to apply to 5.15-stable tree To: ruanjinjie@huawei.com,maddy@linux.ibm.com,sourabhjain@linux.ibm.com Cc: From: Date: Wed, 09 Sep 2026 11:52:25 +0200 Message-ID: <2026090925-sliceable-cold-552f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x fa40f9dbdd4af53e7445d9135b5b207eb8adf372 # git commit -s git send-email --to '' --in-reply-to '2026090925-sliceable-cold-552f@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From fa40f9dbdd4af53e7445d9135b5b207eb8adf372 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 29 Jul 2026 09:29:48 +0800 Subject: [PATCH] powerpc/kexec_file: Prevent kexec range truncation Sashiko AI review pointed out the following issue. The __merge_memory_ranges() function incorrectly handles overlapping memory ranges when merging them. Although sort_memory_ranges() sorts all ranges by their start address in ascending order beforehand, the merge logic remains defective in two ways: 1. It compares the current range's start against the previous element (i-1) instead of the running target index (idx) 2. It unconditionally overwrites 'ranges[idx].end' with 'ranges[i].end'. This logic flaw leads to critical memory truncation when a larger memory range completely subsumes subsequent smaller ranges. For example, consider a sorted input array with three ranges: Range A (idx=0): [0x1000 - 0x9000] Range B (i=1): [0x2000 - 0x5000] (completely inside Range A) Range C (i=2): [0x6000 - 0x8000] (completely inside Range A) 1. When i=1 (Range B): ranges[1].start (0x2000) <= ranges[0].end + 1 (0x9001) is TRUE. The code executes: ranges[0].end = ranges[1].end, which erroneously shrinks Range A's end from 0x9000 down to 0x5000. 2. When i=2 (Range C): ranges[2].start (0x6000) <= ranges[1].end + 1 (0x5001) is FALSE. The code falls into the else block, creating a broken new range. As a result, valid memory fragments [0x5001 - 0x5fff] and [0x8001 - 0x9000] are completely lost from the kexec exclude lists, potentially allowing the crash kernel to overwrite active memory, causing data corruption or crashes. Fix this by ensuring the start of the current range is compared against the end of the active merged range (idx), and use max() to safely prevent the outer boundary from being truncated. Cc: stable@vger.kernel.org Fixes: 180adfc532a8 ("powerpc/kexec_file: Add helper functions for getting memory ranges") Signed-off-by: Jinjie Ruan Reviewed-by: Sourabh Jain Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260729012948.2797865-4-ruanjinjie@huawei.com diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c index 867135560e5c..eb45e89502ca 100644 --- a/arch/powerpc/kexec/ranges.c +++ b/arch/powerpc/kexec/ranges.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -105,19 +106,16 @@ static void __merge_memory_ranges(struct crash_mem *mem_rngs) struct range *ranges; int i, idx; - if (!mem_rngs) + if (!mem_rngs || mem_rngs->nr_ranges <= 1) return; idx = 0; - ranges = &(mem_rngs->ranges[0]); + ranges = mem_rngs->ranges; for (i = 1; i < mem_rngs->nr_ranges; i++) { - if (ranges[i].start <= (ranges[i-1].end + 1)) - ranges[idx].end = ranges[i].end; + if (ranges[i].start <= (ranges[idx].end + 1)) + ranges[idx].end = max(ranges[idx].end, ranges[i].end); else { idx++; - if (i == idx) - continue; - ranges[idx] = ranges[i]; } }