From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.9 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794466839; b=I93x6YBS7ITAuQWkXVqACTEsggMoSd24kbB0ixaAL2UdNmMDVn1tKJL54u4m2by1kaor FSXDnbjjWrJeHE0A1TX9i4tpY/dbRgdljZYUH4yz6WagWD1cDKxku1NRmDW2ai4T0yuRU x+DjNPhkNoS0I7ICDBcJHWymWW0YubM/2xi8CN9dxXNZBYHcquME/89KVMV9Wju5/6Qvc SMpBkxdcgER6LS+ucFY0CkrplTprsgKYTtOg26V4E5Gp7o2ZXcGtR1zZ7d/PsFHAUppJs QgnrGFxH0KFIesHOysbww1ZqvZUbCATiNff3wjFI5gLISra0GpqO21ecFKgf3Mam31g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794466839; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:Content-Language:From:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=J4xIggD0g8SlhhtdOwMFrAXrBVevW/MmjFyooXoSNeE=; b=18zXr9OUTRGyBbzNOHyHRgYImYP1D2C1JAzRjrG8W6PAM9uL5lD54PXE0O0GanLuw/sC fvhMprhlvTrrFDI7Nn5YqBimcmZdwxVH28MaSNjCM67odpnx/xDcu0wZ/VJCc2g6aWMZd V/sf6HmD67bzkBNAAzpp/6VVRpBsy96ebQxlfpaT7jro9WENSr0kXgoj6AH8JHEiB9OdT ULlb2+DzwqWL8twTmgyHNf0RPkzD1mvKcAGJIMiUpIRqzpbcFmMrLKb555OSBnTb4f/ha 0tZo/cTMyfm3dCK8xsijOzUzRmalSrg15N7lCvP+rDMaAT3LSaqPl7lzKGfLN9wjltg== 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=owLrm7cB; arc=none smtp.remote-ip=95.215.58.9 Received: from mta1.migadu.com (out-9.mta1.migadu.com [95.215.58.9]) (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 8D79A606A31C for ; Thu, 12 Nov 2026 07:00:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 8D79A606A31C 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=owLrm7cB X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=IWVkZhORY9imY5FneS+keJKgSYCeTxoJHysJ7YNaF+Y=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794466836; v=1; x=1795071636; b=owLrm7cBfzN1UV7R16E1C54SoQ6uEbb9iF8oE9Q5nwcgoWHQirDw5gp7jkGwGjeLafzaGCP1 Te46sEi7bhxP9cwDDRW2wHBKzqLnYx5iq1pmrfxW0YYJxKqEKpde6mzEEQo7PWPyTvt+znR0GhH xNDE2eDuB7safnAL4u5eo6JM= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 5f9d5e168c7f5611; Thu, 12 Nov 2026 07:00:23 +0000 X-Mizu-Trace-ID: 5f9d5e168c7f5611 X-Migadu-Flow: FLOW_OUT Message-ID: <4ad546a2-66c5-4b74-a221-d9e8c1006c73@linux.dev> Date: Thu, 12 Nov 2026 15:01:48 +0800 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 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 6/9] mm/vmalloc: only flush the cache after the vmap succeeded To: Suren Baghdasaryan Cc: Uladzislau Rezki , Dev Jain , Andrew Morton , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Dennis Zhou , Tejun Heo , Christoph Lameter , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Sashiko References: <20261110112546.261415-1-hao.ge@linux.dev> <20261110112546.261415-7-hao.ge@linux.dev> Content-Language: en-US From: Hao Ge In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 2026/11/12 08:30, Suren Baghdasaryan wrote: > On Tue, Nov 10, 2026 at 11:25 AM Hao Ge wrote: >> >> vmap_page_range() and __vmap_pages_range() call flush_cache_vmap() > > New vmap_pages_range_batched() function has the same issue, so needs fixing too. Ack. will do next version. > >> before they even look at the error code. A failed mapping is never >> used, so the flush is pointless at best. >> >> According to the Sashiko review it is worse than pointless on UML: >> flush_cache_vmap() there is flush_tlb_kernel_range(), which syncs the >> PTEs into the host OS. Flushing a half-installed mapping therefore >> leaves host mappings behind for a range that was just freed again. >> >> Only flush when the mapping, and for vmap_page_range() also the KMSAN >> metadata, is fully set up. >> >> Reported-by: Sashiko >> Signed-off-by: Hao Ge >> --- >> mm/vmalloc.c | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >> index 0565cbfe325c..3f98056f8c7e 100644 >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -369,10 +369,12 @@ int vmap_page_range(unsigned long addr, unsigned long end, >> >> err = vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot), >> ioremap_max_page_shift); >> - flush_cache_vmap(addr, end); >> if (!err) >> err = kmsan_ioremap_page_range(addr, end, phys_addr, prot, >> ioremap_max_page_shift); >> + if (!err) >> + flush_cache_vmap(addr, end); >> + >> return err; >> } >> >> @@ -758,7 +760,9 @@ static int __vmap_pages_range(unsigned long addr, unsigned long end, >> int err; >> >> err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift, gfp_mask); >> - flush_cache_vmap(addr, end); >> + if (!err) >> + flush_cache_vmap(addr, end); >> + >> return err; >> } >> >> -- >> 2.25.1 >>