From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (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 CB1243D5C32 for ; Fri, 17 Jul 2026 07:03:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784271806; cv=none; b=QqKRH09f/YisKDQCbghO0/QX6bA/AWEs8PeL7NGCkTqNIQ5nyYX42mx0RpmNP25JB148ziTbkLsoKgR1cJi60bwt1O+da0z2BA+uarN5vgulgpYYPyN7N15LLT98BRFMi+/tiSoGFx9Hszcm60/Kd/ZJRu5Wa8HgsQATgUO/ag0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784271806; c=relaxed/simple; bh=bk8S0aq67C4/1YG1nYalFFib8wYN9jCAvj9WGRVobwk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=PzyQgGw6qdBwRKJjCFjFrYHFoimzg/XcCBYGP/dcP+VCRJeO3k/4QDcUK+6qNx7yHjGmPWM/3ZO3cXgL/kjyKUwuHmIj6vIILcuWSOhZ+pEvU6gDZ7es66CIeZL/qZ6UzZ3juNyIFIr/hINIAlPdrNJGYOrqLw53RtUKdWD4IJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=LFWcRMMZ; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="LFWcRMMZ" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784271801; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=z8nty2Cb7mt9YgTiJdrfdlvIVrvucL4Q1GJIZGhzmKI=; b=LFWcRMMZC3ARLQWT4SjdxAGcKL8fbEaE50vua4PcsSiuQVzWqpj2o2VTZ8d32o/Y5iltB0 JrY3G0HQcQStbJEORWi0tLNNlPdaH5+xYCUxADZmgw/AF9tB9nfQ4Vk82qS9+jJHfX7NAg MJ9UJQB3AFFY+k2/7NvkzZ6JMf8ZPNg= From: Hongfu Li To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, hongfu.li@linux.dev, Hongfu Li Subject: [PATCH] selftests/mm: Fix BUG_ON checking wrong variable in mremap_dontunmap Date: Fri, 17 Jul 2026 15:02:51 +0800 Message-ID: <20260717070251.73212-1-hongfu.li@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Hongfu Li In mremap_dontunmap_partial_mapping_overwrite(), mremap() stores its returned remapped address into remapped_mapping, while the BUG_ON incorrectly checks dest_mapping instead. If mremap() fails, dest_mapping still holds a valid pointer obtained from the prior mmap() call, making this BUG_ON never trigger at all. Correct the check to validate the actual mremap() return value stored in remapped_mapping. Signed-off-by: Hongfu Li --- tools/testing/selftests/mm/mremap_dontunmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/mremap_dontunmap.c b/tools/testing/selftests/mm/mremap_dontunmap.c index a4f75d836733..96ba537facf7 100644 --- a/tools/testing/selftests/mm/mremap_dontunmap.c +++ b/tools/testing/selftests/mm/mremap_dontunmap.c @@ -313,7 +313,7 @@ static void mremap_dontunmap_partial_mapping_overwrite(void) mremap(source_mapping, 5 * page_size, 5 * page_size, MREMAP_DONTUNMAP | MREMAP_MAYMOVE | MREMAP_FIXED, dest_mapping); - BUG_ON(dest_mapping == MAP_FAILED, "mremap"); + BUG_ON(remapped_mapping == MAP_FAILED, "mremap"); BUG_ON(dest_mapping != remapped_mapping, "expected to remap to dest_mapping"); BUG_ON(check_region_contains_byte(source_mapping, 5 * page_size, 0) != -- 2.54.0