From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.201 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792994976; b=Q2cDHHeDVfV7NU65H18svkYkKtEDhkyU9QeLizgjGNwZQVsB/SLivvWf5DBbytVgoM3/ kby0d24KhEYbJ/lcxiggUfETXkRBcsskT8VZVQxKxxJKNvkv79YNhzj26RyUdxpt4VmjY ZaSEcBrkbzCdPr/InO3mQoIcKJmYjfEn4p+XPJobO2AXHtp8xUmGRLwAhq9JuZW9qfMIY OdQzmEO8fvJZXu/M51i5+9YiPxqxpL8YG1VBbwFu1GejwovIXSkkZeyW/n2ll0zX6WD5C SLLf5hPrEZe/AsVDAFrSMPIbx6WoBFeF8lw2WFAulhzmGQdIBS2etJqFuUSS7Xh10kw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792994976; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:Date:Subject:MIME-Version: Content-Type:Content-Transfer-Encoding:Message-Id:References: In-Reply-To:To:Cc:X-Mailer; bh=LRO5qjnwALlrQa/AL5APisjMR4z2O+zqds9mzHpxSAU=; b=m4DNZiG9ZbnHz7uoobEYM5kaYFdEmZrdowlNDMTGeSfyv4Ts6Yi9hdrCqcAcaw87DdvY Ndvb1Lt4o8Oc8GGY8alamGmdsKjheDe3kerimra5O18eYONbWHtL/5eZEpjI8V9GM76sk RMR1EPzN7ENEE0hG81sBRd8eyA2yP8j3OK8mpvM/znjxv37aWyQZNhQj3v8SCEoKrfPSX OUzUDdAoBB6ukf78ojMIIMX7+gXcGYF7EUJCvCn0aH8R7Qh1uWNUsyko9hKf2Df0iaSu1 5MsFIbI4meeAJ9P/fgu+DWODDzFe57QJ31YPb4qq/oVZ+YA4aBDF9XIsrEtY52ObMxA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b="nOLT5lV/"; arc=none smtp.remote-ip=95.215.58.201 Received: from mta1.migadu.com (out-201.mta1.migadu.com [95.215.58.201]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 56DC0606A31F for ; Mon, 26 Oct 2026 06:09:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 56DC0606A31F 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, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=nOLT5lV/ X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=uaY+B1fHFP1ahLgB0T3Rk+kqqo7Xd5Z1Iz1h35K6LdY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792994973; v=1; x=1793599773; b=nOLT5lV/D9H6z5XSR8y/VBJHt9xb7rxn1Z396Z4ctj1Qx+3WlSkuu7qB7kprGEaCjpVxG5O0 g63D+Y6IXTEQ0m6kpw/R4QsWnvFKeGTU1ZKVac/bkMOpFYTxgfPtfVEFNtAjMfxHkBSF8+hJDIN tXteDGLbnNHuSJNOb7pJxah0= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 530052733c7de91c; Mon, 26 Oct 2026 06:09:33 +0000 X-Mizu-Trace-ID: 530052733c7de91c X-Migadu-Flow: FLOW_OUT From: Ye Liu Date: Mon, 26 Oct 2026 14:09:23 +0800 Subject: [PATCH 1/2] mm/vmalloc: drop VM_DMA_COHERENT from remap_vmalloc_range_partial 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: 7bit Message-Id: <20261026-vmalloc_remap-v1-1-b7a907814e90@linux.dev> References: <20261026-vmalloc_remap-v1-0-b7a907814e90@linux.dev> In-Reply-To: <20261026-vmalloc_remap-v1-0-b7a907814e90@linux.dev> To: Andrew Morton , Uladzislau Rezki Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ye Liu X-Mailer: b4 0.17-dev-39d60 From: Ye Liu No caller maps a VM_DMA_COHERENT area through this path: such areas come from dma_alloc_coherent() internals and are freed via vunmap(), never through remap_vmalloc_range[_partial](); all 13 callers pass vmalloc_user()/vmalloc()-backed addresses. The flag was added in commit fe9041c245196 ("vmalloc: lift the arm flag for coherent mappings to common code") as a mechanical translation of ARM's VM_ARM_DMA_CONSISTENT. It is also unsafe to keep since commit 5ea8ec74c57c0 ("mm/vmalloc: free unused pages on vrealloc() shrink"), which frees tail pages of non-VM_USERMAP areas (VM_DMA_COHERENT is not in that skip-list): a shrunk-then-mapped area would hit vmalloc_to_page()==NULL and vm_insert_page() would dereference it unchecked. Drop it so DMA-coherent areas can never enter the path. Signed-off-by: Ye Liu --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index db669103dc66..a888eca016a8 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4894,7 +4894,7 @@ int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr, if (!area) return -EINVAL; - if (!(area->flags & (VM_USERMAP | VM_DMA_COHERENT))) + if (!(area->flags & VM_USERMAP)) return -EINVAL; if (check_add_overflow(size, off, &end_index) || -- 2.43.0