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Message-Id: <1434839566-31704-1-git-send-email-alex.popov@linux.com>
Date: Sun, 21 Jun 2015 01:32:46 +0300
From: Alexander Popov <alex.popov@...ux.com>
To: Pantelis Antoniou <pantelis.antoniou@...il.com>,
Vitaly Bordug <vbordug@...mvista.com>,
Leroy Christophe <christophe.leroy@....fr>,
David Miller <davem@...emloft.net>,
Alexander Popov <alex.popov@...ux.com>,
linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/1] net: fs_enet: Fix NETIF_F_SG feature for Freescale MPC5121
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 <EE,ME,IR,DR,RI> 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 <alex.popov@...ux.com>
---
.../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
--
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