Am Dienstag, 3. Mai 2011, 00:52:14 schrieb David Miller: > From: tom.leiming@xxxxxxxxx > Date: Fri, 29 Apr 2011 16:37:09 +0800 > > > From: Ming Lei <tom.leiming@xxxxxxxxx> > > > > This patch makes use of the EVENT_DEV_OPEN flag introduced recently to > > fix one out of memory issue, which can be reproduced on omap3/4 based > > pandaboard/beagle XM easily with steps below: > ... > > Oliver please review this patch. Thanks! > > > - enable runtime pm > > echo auto > /sys/devices/platform/usbhs-omap.0/ehci-omap.0/usb1/1-1/1-1.1/power/control > > > > - ifconfig eth0 up > > > > - then out of memroy happened, see [1] for kernel message. > > > > Follows my analysis: > > - 'ifconfig eth0 up' brings eth0 out of suspend, and usbnet_resume > > is called to schedule dev->bh, then rx urbs are submited to prepare for > > recieving data; > > > > - some usbnet devices will produce garbage rx packets flood if > > info->reset is not called in usbnet_open. > > > > - so there is no enough chances for usbnet_bh to handle and release > > recieved skb buffers since many rx interrupts consumes cpu, so out of memory > > for atomic allocation in rx_submit happened. > > > > This patch fixes the issue by simply not allowing schedule of usbnet_bh until device > > is opened. Do the devices in question use cdc_ether? The problem I see with this patch is that cdc_ether uses .reset_resume = usbnet_resume Therefore the device will not have been reset from the viewpoint of the device, yet the device may be open, so the bug would strike again. It seems to me that this patch is not wrong as such, but incomplete. Regards Oliver -- - - - SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg) Maxfeldstraße 5 90409 Nürnberg Germany - - - -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
