On Thu, Dec 01, 2016 at 12:05:34PM +0300, Andrey Ryabinin wrote: > > > On 12/01/2016 02:10 AM, Josh Poimboeuf wrote: > > Resuming from a suspend operation is showing a KASAN false positive > > warning: > > > > > KASAN instrumentation poisons the stack when entering a function and > > unpoisons it when exiting the function. However, in the suspend path, > > some functions never return, so their stack never gets unpoisoned, > > resulting in stale KASAN shadow data which can cause false positive > > warnings like the one above. > > > > Reported-by: Scott Bauer <scott.ba...@intel.com> > > Tested-by: Scott Bauer <scott.ba...@intel.com> > > Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> > > --- > > arch/x86/kernel/acpi/sleep.c | 3 +++ > > include/linux/kasan.h | 7 +++++++ > > 2 files changed, 10 insertions(+) > > > > diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c > > index 4858733..62bd046 100644 > > --- a/arch/x86/kernel/acpi/sleep.c > > +++ b/arch/x86/kernel/acpi/sleep.c > > @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) > > pause_graph_tracing(); > > do_suspend_lowlevel(); > > unpause_graph_tracing(); > > + > > + kasan_unpoison_stack_below_sp(); > > + > > I think this might be too late. We may hit stale poison in the first C > function called > after resume (restore_processor_state()). Thus the shadow must be unpoisoned > prior such call, > i.e. somewhere in do_suspend_lowlevel() after .Lresume_point.
Yeah, I think you're right. Will spin a v2. -- Josh
