From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 751562590 for ; Sun, 22 Jan 2023 15:22:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDAC8C433EF; Sun, 22 Jan 2023 15:22:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1674400928; bh=M+4GISfvltC10De0Z9HQpos6L7S/uXmgMLDdAvSbSE8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VO7wU+MQ+2WQ/dMOT+eLOLB32i8s4gGFRHNk1i+L32F71y6FRzZYdoKJsoI/ZlNri /plR8tFKYLDiH5HraS6HBHRO1QiP4WFKlrkuk1jX+W/5xwAyCrLSNOH6uihN6+DSWl fWnQjt/FSW/zoZaMgWp5ax/d1U8XGgYOuaZIu80A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zach OKeefe , Hugh Dickins , David Hildenbrand , Yang Shi , Andrew Morton Subject: [PATCH 6.1 045/193] mm/shmem: restore SHMEM_HUGE_DENY precedence over MADV_COLLAPSE Date: Sun, 22 Jan 2023 16:02:54 +0100 Message-Id: <20230122150248.456581237@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230122150246.321043584@linuxfoundation.org> References: <20230122150246.321043584@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Zach O'Keefe commit 3de0c269adc6c2fac0bb1fb11965f0de699dc32b upstream. SHMEM_HUGE_DENY is for emergency use by the admin, to disable allocation of shmem huge pages if, for example, a dangerous bug is found in their usage: see "deny" in Documentation/mm/transhuge.rst. An app using madvise(,,MADV_COLLAPSE) should not be allowed to override it: restore its precedence over shmem_huge_force. Restore SHMEM_HUGE_DENY precedence over MADV_COLLAPSE. Link: https://lkml.kernel.org/r/20221224082035.3197140-2-zokeefe@google.com Fixes: 7c6c6cc4d3a2 ("mm/shmem: add flag to enforce shmem THP in hugepage_vma_check()") Signed-off-by: Zach O'Keefe Suggested-by: Hugh Dickins Acked-by: David Hildenbrand Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/shmem.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/mm/shmem.c +++ b/mm/shmem.c @@ -472,12 +472,10 @@ bool shmem_is_huge(struct vm_area_struct if (vma && ((vma->vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))) return false; - if (shmem_huge_force) - return true; - if (shmem_huge == SHMEM_HUGE_FORCE) - return true; if (shmem_huge == SHMEM_HUGE_DENY) return false; + if (shmem_huge_force || shmem_huge == SHMEM_HUGE_FORCE) + return true; switch (SHMEM_SB(inode->i_sb)->huge) { case SHMEM_HUGE_ALWAYS: