From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 C17E125333F for ; Wed, 10 Jun 2026 12:13:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781093626; cv=none; b=LqwKUozcxb0U+CnP4LiBXgbl0Z4MqEu5/clPWrg4azPrlUzgaYMChFKC3tS2y8jKWRappOHe2oWng9qeu6+gkjeQZXfA8q57ul2iqxqCMheOiTwX2CiRVksGO74pViMsFS33eB/7pw7uo6GwxH+JEpPL6AYQhyLrDDHjcWApnGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781093626; c=relaxed/simple; bh=3tOm4nsDKVLlgjuHeDHdJzT1QrjLiA2mSDCmk2v/7rk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=pSDu9uqtQ0bk4DpaGeIp++5FkVPUH+I5Fb5FNab2dw8D9I9fH5O/vYCbiznS3DjmPND4H00D6VQypvheTmvuSQUGe+09vS+2bfp6OWkuXYmgQsSwB4pZUOfOdBJ4lzRO2Xtl2gvJDaOcx/109pUb6Viyi8FmMcKB2wFg77hMgUU= 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=kHZon/L9; arc=none smtp.client-ip=95.215.58.173 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="kHZon/L9" 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=1781093622; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Pwj8jdIsbpLPyXeeuKlvHP7KUJNAfbD2TmuqoyWPWCs=; b=kHZon/L9Rk/OuUATUmtFgYllI2r2VhkBLqmv89mnUttaPtOwahpgGto4qvMwY+P5M8q+Sc bOh4wFR3Pb39+NVgs12G8vkD7YnjH6QtsLeH+v8duM5y05J2iPXUhWJ0ARLdQeKQl4GwXZ LyF/A2b9YFG/Dl/fKi3rESfZcTfxukc= From: Lance Yang To: baolin.wang@linux.alibaba.com Cc: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, hughd@google.com, willy@infradead.org, ziy@nvidia.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 04/11] mm: khugepaged: add shmem mTHP collapse support Date: Wed, 10 Jun 2026 20:13:31 +0800 Message-Id: <20260610121331.83926-1-lance.yang@linux.dev> In-Reply-To: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> References: <3895c09794739bbfae99d9e021ffacf8a51fb8e2.1781083630.git.baolin.wang@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Wed, Jun 10, 2026 at 06:29:12PM +0800, Baolin Wang wrote: [...] >@@ -2808,7 +2875,7 @@ static enum scan_result collapse_single_pmd(unsigned long addr, > mmap_read_unlock(mm); > *lock_dropped = true; > retry: >- result = collapse_scan_file(mm, addr, file, pgoff, cc); >+ result = collapse_scan_file(mm, vma, addr, file, pgoff, cc); Looks unsafe to pass "vma" down here, since we have already dropped mmap_read_unlock(mm) ... A racing munmap() could leave it stale before collapse_scan_file() use it, no? Cheers, Lance