From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57910 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752274AbcKRKga (ORCPT ); Fri, 18 Nov 2016 05:36:30 -0500 Subject: Patch "bpf: fix htab map destruction when extra reserve is in use" has been added to the 4.8-stable tree To: daniel@iogearbox.net, ast@kernel.org, davem@davemloft.net, dvyukov@google.com, gregkh@linuxfoundation.org Cc: , From: Date: Fri, 18 Nov 2016 11:36:34 +0100 Message-ID: <147946539488220@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled bpf: fix htab map destruction when extra reserve is in use to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-fix-htab-map-destruction-when-extra-reserve-is-in-use.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Fri Nov 18 11:35:46 CET 2016 From: Daniel Borkmann Date: Fri, 4 Nov 2016 00:01:19 +0100 Subject: bpf: fix htab map destruction when extra reserve is in use From: Daniel Borkmann [ Upstream commit 483bed2b0ddd12ec33fc9407e0c6e1088e77a97c ] Commit a6ed3ea65d98 ("bpf: restore behavior of bpf_map_update_elem") added an extra per-cpu reserve to the hash table map to restore old behaviour from pre prealloc times. When non-prealloc is in use for a map, then problem is that once a hash table extra element has been linked into the hash-table, and the hash table is destroyed due to refcount dropping to zero, then htab_map_free() -> delete_all_elements() will walk the whole hash table and drop all elements via htab_elem_free(). The problem is that the element from the extra reserve is first fed to the wrong backend allocator and eventually freed twice. Fixes: a6ed3ea65d98 ("bpf: restore behavior of bpf_map_update_elem") Reported-by: Dmitry Vyukov Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/hashtab.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -687,7 +687,8 @@ static void delete_all_elements(struct b hlist_for_each_entry_safe(l, n, head, hash_node) { hlist_del_rcu(&l->hash_node); - htab_elem_free(htab, l); + if (l->state != HTAB_EXTRA_ELEM_USED) + htab_elem_free(htab, l); } } } Patches currently in stable-queue which might be from daniel@iogearbox.net are queue-4.8/dctcp-avoid-bogus-doubling-of-cwnd-after-loss.patch queue-4.8/bpf-fix-htab-map-destruction-when-extra-reserve-is-in-use.patch