> -----Original Message----- > From: Dan Carpenter > Sent: Friday, August 29, 2014 17:50 PM > To: KY Srinivasan > Cc: Sitsofe Wheeler; Dexuan Cui; Greg Kroah-Hartman; Haiyang Zhang; > linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PANIC, hyperv] BUG: unable to handle kernel paging request at > ffff880077800004 (hv_ringbuffer_write) > > It's sort of weird that this is an alignment issue. The config that > was posted earlier was an x86_64 config and on that system then the > pointers from kmalloc() should already be aligned correctly at > sizeof(u64). > > Earlier I said I suspected the code is racy, so possibly changing from > kmalloc() to get_zeroed_page() just changes the timing enough so we > don't see the race condition. > > regards, > dan carpenter Hi Dan, Section 4.11.3 of Hypervisor Top Level Functional Specification(available at http://blogs.msdn.com/b/virtual_pc_guy/archive/2014/02/17/updated-hypervisor-top-level-functional-specification.aspx) says HV_STATUS_INVALID_ALIGNMENT can also be returned for a hypercall if "the specified input or output parameter lists spans pages." My understanding is: the input's memory range shouldn't cross a page boundary. Thanks, -- Dexuan _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
