From patchwork Mon Sep 26 08:31:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 12988376 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B167FC07E9D for ; Mon, 26 Sep 2022 08:32:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234376AbiIZIcq (ORCPT ); Mon, 26 Sep 2022 04:32:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234353AbiIZIcn (ORCPT ); Mon, 26 Sep 2022 04:32:43 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FCA736862; Mon, 26 Sep 2022 01:32:41 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ocjXL-00030q-0S; Mon, 26 Sep 2022 10:32:23 +0200 From: Florian Westphal To: Cc: tgraf@suug.ch, urezki@gmail.com, Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Florian Westphal , Martin Zaharinov , Michal Hocko , Paolo Bonzini , kvm@vger.kernel.org Subject: [PATCH net] rhashtable: fix crash due to mm api change Date: Mon, 26 Sep 2022 10:31:39 +0200 Message-Id: <20220926083139.48069-1-fw@strlen.de> X-Mailer: git-send-email 2.37.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Martin Zaharinov reports BUG() in mm land for 5.19.10 kernel: kernel BUG at mm/vmalloc.c:2437! invalid opcode: 0000 [#1] SMP CPU: 28 PID: 0 Comm: swapper/28 Tainted: G W O 5.19.9 #1 [..] RIP: 0010:__get_vm_area_node+0x120/0x130 __vmalloc_node_range+0x96/0x1e0 kvmalloc_node+0x92/0xb0 bucket_table_alloc.isra.0+0x47/0x140 rhashtable_try_insert+0x3a4/0x440 rhashtable_insert_slow+0x1b/0x30 [..] bucket_table_alloc uses kvzalloc(GPF_ATOMIC). If kmalloc fails, this now falls through to vmalloc and hits code paths that assume GFP_KERNEL. I sent a patch to restore GFP_ATOMIC support in kvmalloc but mm maintainers rejected it. This patch is partial revert of commit 93f976b5190d ("lib/rhashtable: simplify bucket_table_alloc()"), to avoid kvmalloc for ATOMIC case. As kvmalloc doesn't warn when used with ATOMIC, kernel will only crash once vmalloc fallback occurs, so we may see more crashes in other areas in the future. Most other callers seem ok but kvm_mmu_topup_memory_cache looks like it might be affected by the same breakage, so Cc kvm@. Reported-by: Martin Zaharinov Fixes: a421ef303008 ("mm: allow !GFP_KERNEL allocations for kvmalloc") Link: https://lore.kernel.org/linux-mm/Yy3MS2uhSgjF47dy@pc636/T/#t Cc: Michal Hocko Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Signed-off-by: Florian Westphal --- lib/rhashtable.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index e12bbfb240b8..9451f411bc71 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -181,7 +181,13 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, int i; static struct lock_class_key __key; - tbl = kvzalloc(struct_size(tbl, buckets, nbuckets), gfp); + size = struct_size(tbl, buckets, nbuckets); + + /* kvmalloc API does not support GFP_KERNEL anymore */ + if ((gfp & GFP_KERNEL) != GFP_KERNEL) + tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY); + else + tbl = kvzalloc(size, gfp); size = nbuckets;