From 7c1e7e99ab8fac65222cfc0a2cc35f3678086cfa Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Mon, 4 Feb 2013 09:49:42 +0000 Subject: [PATCH] gianfar: dont conditionally alloc Rx/Err irq structs Commit ee873fda3bec7c668407b837fc5519eb961fcd37 "gianfar: Pack struct gfar_priv_grp into three cachelines" causes the following null dereference at driver init on sbc8548: libphy: Freescale PowerQUICC MII Bus: probed Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc01d6a38 Oops: Kernel access of bad area, sig: 11 [#1] [...] NIP [c01d6a38] gfar_parse_group+0x228/0x280 LR [c01d6a34] gfar_parse_group+0x224/0x280 Call Trace: [ef82dd60] [c01d6a34] gfar_parse_group+0x224/0x280 (unreliable) [ef82dd90] [c01d73a4] gfar_probe+0x284/0xfe0 The reason is that the commit also changed the allocation of the Rx and error handling irq structs to be skipped for !MQ_MG_MODE. In the !MQ_MG_MODE case, only the Tx irq struct is allocated. Digging further, we see that MQ_MG_MODE is set only if we find the OF compatible string "fsl,etsec2". A quick grep in the dts directory shows lots of boards that support Rx/Tx/Err, but without this specific compat string. And hence they go after the unallocated Rx/Error structs and cause the above oops. Hence such a change can not be deployed until all the dts files are updated and sufficiently deployed. Further, the optimization is of limited value, since the kmalloc'd struct in question has only a single unsigned int, and an (IFNAMSIZ + 6) sized string. Note that no changes to the freeing code are needed here, as it already did an unconditional free of Rx/Tx/Error gfar_irqinfo. Cc: Claudiu Manoil Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/gianfar.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c index 19c54a0acb56..75734bfed10f 100644 --- a/drivers/net/ethernet/freescale/gianfar.c +++ b/drivers/net/ethernet/freescale/gianfar.c @@ -580,19 +580,11 @@ static int gfar_parse_group(struct device_node *np, u32 *queue_mask; int i; - if (priv->mode == MQ_MG_MODE) { - for (i = 0; i < GFAR_NUM_IRQS; i++) { - grp->irqinfo[i] = kzalloc(sizeof(struct gfar_irqinfo), - GFP_KERNEL); - if (!grp->irqinfo[i]) - return -ENOMEM; - } - } else { - grp->irqinfo[GFAR_TX] = kzalloc(sizeof(struct gfar_irqinfo), - GFP_KERNEL); - if (!grp->irqinfo[GFAR_TX]) + for (i = 0; i < GFAR_NUM_IRQS; i++) { + grp->irqinfo[i] = kzalloc(sizeof(struct gfar_irqinfo), + GFP_KERNEL); + if (!grp->irqinfo[i]) return -ENOMEM; - grp->irqinfo[GFAR_RX] = grp->irqinfo[GFAR_ER] = NULL; } grp->regs = of_iomap(np, 0); -- 2.20.1