From: Paul Gortmaker Date: Mon, 4 Feb 2013 09:49:42 +0000 (+0000) Subject: gianfar: dont conditionally alloc Rx/Err irq structs X-Git-Tag: v3.9-rc1~139^2~167 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c1e7e99ab8fac65222cfc0a2cc35f3678086cfa;p=pandora-kernel.git 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 --- Reading git-diff-tree failed