Messages in this thread | | | Date | Fri, 10 Nov 2017 13:56:32 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v5 2/3] x86/topology: Avoid wasting 128k for package id array |
| |
On Fri, 10 Nov 2017, Thomas Gleixner wrote:
> On Fri, 10 Nov 2017, Prarit Bhargava wrote: > > On 11/09/2017 07:43 PM, Thomas Gleixner wrote: > > > On Sun, 5 Nov 2017, Prarit Bhargava wrote: > > >> [v5]: Change kmalloc to GFP_ATOMIC to fix "sleeping function" warning on > > >> virtual machines. > > > > > > What has this to do with virtual machines? The very same issue is on > > > physcial hardware because this is called from the early CPU bringup code > > > with interrupts and preemption disabled. > > > > There was a Intel test bot report of a failure during boot on virtual systems > > with Andi's patch. > > Sure, but the problem has nothing to do with virtual machines at all.
The same is true for the KASAN report of out of bound access:
new = logical_packages++; - if (new != pkg) { - pr_info("CPU %u Converting physical %u to logical package %u\n", - cpu, pkg, new); + + /* Allocate and copy a new array */ + ltp_pkg_map_new = kmalloc(logical_packages * sizeof(u16), GFP_KERNEL); + BUG_ON(!ltp_pkg_map_new); + if (logical_to_physical_pkg_map) { + memcpy(ltp_pkg_map_new, logical_to_physical_pkg_map, + logical_packages * sizeof(u16));
That's caused by incrementing logical_packages _before_ the memcpy(), but the old array is one u16 shorter than the newly allocated.
That's reported on a VM as well, but is a genuine code bug.
Thanks,
tglx
| |