Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755525AbbFTWdU (ORCPT ); Sat, 20 Jun 2015 18:33:20 -0400 Received: from mail-lb0-f171.google.com ([209.85.217.171]:33038 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752234AbbFTWdL (ORCPT ); Sat, 20 Jun 2015 18:33:11 -0400 From: Alexander Popov To: Pantelis Antoniou , Vitaly Bordug , Leroy Christophe , David Miller , Alexander Popov , linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/1] net: fs_enet: Fix NETIF_F_SG feature for Freescale MPC5121 Date: Sun, 21 Jun 2015 01:32:46 +0300 Message-Id: <1434839566-31704-1-git-send-email-alex.popov@linux.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4770 Lines: 132 Commit 4fc9b87bae25 ("net: fs_enet: Implement NETIF_F_SG feature") brings a trouble to Freescale MPC512x: a kernel oops happens during sending non-linear sk_buff with .data not aligned by 4. Log quotation: Unable to handle kernel paging request for data at address 0xe467c000 Faulting instruction address: 0xc000cd44 Oops: Kernel access of bad area, sig: 11 [#1] MPC512x generic Modules linked in: CPU: 0 PID: 984 Comm: kworker/0:1H Not tainted 4.1.0-rc8-00024-gbb16140 #2 Workqueue: rpciod rpc_async_schedule task: cf364a50 ti: cf362000 task.ti: cf362000 NIP: c000cd44 LR: c000c720 CTR: 00000206 REGS: cf363ac0 TRAP: 0300 Not tainted (4.1.0-rc8-00024-gbb16140) MSR: 00009032 CR: 42004082 XER: 00000000 DAR: e467c000 DSISR: 20000000 GPR00: c0279e24 cf363b70 cf364a50 e467c000 00000206 0000001f 00000001 00000001 GPR08: 00000000 e467c000 e46800be 000139a6 82002082 00000000 c002e46c cf3c3680 GPR16: c044cb30 c04b0000 cf363c48 00000000 00000001 fde0315c 00000000 0000000b GPR24: 0000002c 000040be cf339aa0 0000000b 00000001 cf873210 00282f85 00000000 NIP [c000cd44] clean_dcache_range+0x1c/0x30 LR [c000c720] dma_direct_map_page+0x40/0x94 Call Trace: [cf363b70] [cf339b60] 0xcf339b60 (unreliable) [cf363b90] [c0279e24] fs_enet_start_xmit+0x1c8/0x42c [cf363bd0] [c02ff710] dev_hard_start_xmit+0x2dc/0x3d4 [cf363c40] [c0319c60] sch_direct_xmit+0xcc/0x1cc [cf363c70] [c02ff9c0] __dev_queue_xmit+0x1b8/0x47c [cf363ca0] [c032a3e8] ip_finish_output+0x1fc/0x9a8 [cf363ce0] [c032c31c] ip_send_skb+0x1c/0xa4 [cf363cf0] [c035112c] udp_send_skb+0xe4/0x2e8 [cf363d10] [c0351368] udp_push_pending_frames+0x38/0x84 [cf363d20] [c03537b8] udp_sendpage+0x134/0x174 [cf363d70] [c0384fd4] xs_sendpages+0x21c/0x250 [cf363db0] [c03852bc] xs_udp_send_request+0x50/0xf8 [cf363de0] [c0382f08] xprt_transmit+0x64/0x280 [cf363e20] [c038017c] call_transmit+0x168/0x234 [cf363e40] [c0387918] __rpc_execute+0x88/0x2b0 [cf363e80] [c00296f8] process_one_work+0x124/0x2fc [cf363ea0] [c0029a00] worker_thread+0x130/0x480 [cf363ef0] [c002e528] kthread+0xbc/0xd0 [cf363f40] [c000e4a8] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 7c70faa6 60630800 7c70fba6 4c00012c 4e800020 38a0001f 7c632878 7c832050 7c842a14 5484d97f 4d820020 7c8903a6 <7c00186c> 38630020 4200fff8 7c0004ac ---[ end trace c846c1eceb513c85 ]--- The reason: MPC5121 FEC requires 4-byte alignment for TX data buffer and calls tx_skb_align_workaround() for copying sk_buff with not aligned .data to a new sk_buff with aligned one. But tx_skb_align_workaround() uses skb_copy_from_linear_data() which doesn't work for non-linear sk_buff: a new sk_buff has non-zero nr_frags and zero .data_len. So improve the condition of calling tx_skb_align_workaround() and use skb_linearize() in it. Signed-off-by: Alexander Popov --- .../net/ethernet/freescale/fs_enet/fs_enet-main.c | 26 +++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c index 9b3639e..d92802b 100644 --- a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c +++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c @@ -490,6 +490,9 @@ static struct sk_buff *tx_skb_align_workaround(struct net_device *dev, { struct sk_buff *new_skb; + if (skb_linearize(skb)) + return NULL; + /* Alloc new skb */ new_skb = netdev_alloc_skb(dev, skb->len + 4); if (!new_skb) @@ -515,12 +518,27 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev) cbd_t __iomem *bdp; int curidx; u16 sc; - int nr_frags = skb_shinfo(skb)->nr_frags; + int nr_frags; skb_frag_t *frag; int len; - #ifdef CONFIG_FS_ENET_MPC5121_FEC - if (((unsigned long)skb->data) & 0x3) { + int is_aligned = 1; + int i; + + if (!IS_ALIGNED((unsigned long)skb->data, 4)) { + is_aligned = 0; + } else { + nr_frags = skb_shinfo(skb)->nr_frags; + frag = skb_shinfo(skb)->frags; + for (i = 0; i < nr_frags; i++, frag++) { + if (!IS_ALIGNED(frag->page_offset, 4)) { + is_aligned = 0; + break; + } + } + } + + if (!is_aligned) { skb = tx_skb_align_workaround(dev, skb); if (!skb) { /* @@ -532,6 +550,7 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev) } } #endif + spin_lock(&fep->tx_lock); /* @@ -539,6 +558,7 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev) */ bdp = fep->cur_tx; + nr_frags = skb_shinfo(skb)->nr_frags; if (fep->tx_free <= nr_frags || (CBDR_SC(bdp) & BD_ENET_TX_READY)) { netif_stop_queue(dev); spin_unlock(&fep->tx_lock); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/