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 6CE74223DCE for ; Sat, 18 Jul 2026 10:49:27 +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=1784371768; cv=none; b=rfDhd798ZkflgFrk7tJjSHr7dwhqJXOrXYA2Qz3RmDfuUR+lULHU15IBKyGx3FhrsPNH5irP12l4eCq4yxdbDnwpHUz7xZ0OpkROgXdHRG2vB9+Wbvj0hLTQVODfbgxXpdHyUfitlNRiXdegEDOVVlYoWQskStqlAmSW+SD081w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784371768; c=relaxed/simple; bh=7BHKxFTHJuRmoC80MXXgm1Tdb9t7h5U+X19UFs5m24g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EoY8/ZRF/ya9GBLGPALvqNWrtj3mRXVFrsSFqejHwrN5mPKA5fb2rxdPgB0T+Bae2oWyHT2wBD6eO+ILRRV8s5JyV7UXSqvdGCNVR7EKHNuGaVPXnr90z89lCYmh/z58d1Rrsd1++RsJPV70l7SUZajJQ/Z4gaqjXHXFMq14ntU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bSisULYs; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bSisULYs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F16B1F000E9; Sat, 18 Jul 2026 10:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784371767; bh=Vqk+TTwBA0BAQzINyNQP7BgvRd3meLH2Js/umV4ohBg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bSisULYsLOn/RIwHZ2seWTgJldf9x7ukmTzzreF6gAbsILymCttWYom6Hu/btWb6E tJok3t24xn1w6Yt04xfpzF1LwaEsxyJNftWAx1gZXAReKt97z6wOms/zJMkRkwZwdO Tr1/e9VMbTJlzfXob44GXT8ROUOpZsbXFZPMG6p3m6/fOictlPAb2Xj/q5cuoPA+TC OxBuLfTRItORN7zEndcgqqGyuY8XZWTvftpYYp2oQjZVtPLhqpG4y2S0uHvSBWBKlZ W6DjNM3AQwc2gLvYO3Ncnrjx5dD3WC4iZC3JWuayvDHN82Rgy7A16VkN1UzGeTRfnR jx6lmcubMhUYA== Date: Sat, 18 Jul 2026 13:49:20 +0300 From: Mike Rapoport To: Brendan Jackman Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, brendan.jackman@linux.dev Subject: Re: [PATCH v2] mm/secretmem: don't allow highmem folios Message-ID: References: <20260717-secretmem-highmem-v2-1-1f1a961ca91e@google.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=us-ascii Content-Disposition: inline In-Reply-To: <20260717-secretmem-highmem-v2-1-1f1a961ca91e@google.com> On Fri, Jul 17, 2026 at 09:48:59AM +0000, Brendan Jackman wrote: > secretmem_fault() allocates a folio with GFP_HIGHUSER and then calls > set_direct_map_invalid_noflush() without checking folio_test_highmem(). > This causes a warning and process crash (vibe-coded reproducer in Link > below): ... > Link: https://github.com/bjackman/limmat-kernel-nix/commit/7b2acba2d3a5ef01400d493a155beb1d135b6bb5 > Suggested-by: Andrew Morton > Link: https://lore.kernel.org/all/20260704192603.40aa80cf9242b77aa75e8d8d@linux-foundation.org/ > Fixes: 1507f51255c9f ("mm: introduce memfd_secret system call to create "secret" memory areas") > Signed-off-by: Brendan Jackman Reviewed-by: Mike Rapoport (Microsoft) -- Sincerely yours, Mike.