From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: [PATCH] autofs4: fix 32-bit userspace vs 64-bit kernel communications Date: Wed, 11 Jun 2008 13:54:00 +0400 Message-ID: <484FA0B8.2000002@openvz.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Ian Kent Cc: autofs mailing list , Linux Kernel Mailing List , Konstantin Khlebnikov From: Konstantin Khlebnikov The struct autofs_v5_packet has only one difference between 32-bit and 64-bit versions - on 64-bit gcc aligns its size and it is 4 bytes larger that it is on 32-bit kernel. This confuses 32-bit user-space daemon, when talking to 64-bit kernel. This is very critical for containerized setups, when containers with -bit tolls are used. Signed-off-by: Konstantin Khlebnikov Acked-by: Pavel Emelyanov --- diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c index 1e4a539..9855b6e 100644 --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -132,6 +132,14 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi, struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet; pktsz = sizeof(*packet); +#if defined(CONFIG_X86_64) && defined(CONFIG_IA32_EMULATION) + /* + * On x86_64 autofs_v5_packet struct is padded with 4 bytes + * which breaks 32-bit autofs daemon. + */ + if (test_thread_flag(TIF_IA32)) + pktsz -= 4; +#endif packet->wait_queue_token = wq->wait_queue_token; packet->len = wq->len;