Messages in this thread | | | Subject | Re: [PATCH] [RESEND] [v3] xen: remove pre-xen3 fallback handlers | From | Juergen Gross <> | Date | Tue, 5 Mar 2019 12:28:01 +0100 |
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On 04/03/2019 21:52, Arnd Bergmann wrote: > The legacy hypercall handlers were originally added with > a comment explaining that "copying the argument structures in > HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local > variable is sufficiently safe" and only made sure to not write > past the end of the argument structure, the checks in linux/string.h > disagree with that, when link-time optimizations are used: > > In function 'memcpy', > inlined from 'pirq_query_unmask' at drivers/xen/fallback.c:53:2, > inlined from '__startup_pirq' at drivers/xen/events/events_base.c:529:2, > inlined from 'restore_pirqs' at drivers/xen/events/events_base.c:1439:3, > inlined from 'xen_irq_resume' at drivers/xen/events/events_base.c:1581:2: > include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter > __read_overflow2(); > ^ > > Further research turned out that only Xen 3.0.2 or earlier required the > fallback at all, while all versions in use today don't need it. > As far as I can tell, it is not even possible to run a mainline kernel > on those old Xen releases, at the time when they were in use, only > a patched kernel was supported anyway. > > Fixes: cf47a83fb06e ("xen/hypercall: fix hypercall fallback code for very old hypervisors") > Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Cc: Jan Beulich <JBeulich@suse.com> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pushed to xen/tip.git for-linus-5.1a
Juergen
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