On Fri, Feb 24, 2017 at 11:04:39PM -0600, Josh Poimboeuf wrote: > On Thu, Feb 23, 2017 at 09:10:39PM +0100, Pavel Machek wrote: > > Hi! > > > > > > > > > > Somehow, startup_32_smp() is on the stack twice. The stack unwind > > > > > > led > > > > > > to the startup_32_smp() frame at 0xf50cdf9c rather than the one at > > > > > > 0xf50cdfa8 (which is where it should normally be). So the question > > > > > > is > > > > > > how startup_32_smp() got executed the second time, with the wrong > > > > > > stack > > > > > > offset. > > > > > > > > > > Not much idea... but this is stack dump, right? Just because some > > > > > value is on the stack does not mean it is a return address, no? > > > > > > > > Right, but the one at 0xf50cdfa8 is where the startup_32_smp() is > > > > *supposed* to be. If the unwinder had unwinded to that one, it wouldn't > > > > have complained. So it looks to me like the CPU somehow booted twice: > > > > the first time at the right stack address, and the second time it > > > > somehow ended up with a different stack address. > > > > > > > > > And .... startup_32_smp is kind of "interesting" function. Take a > > > > > look... > > > > > > > > Yes, it's used in bringing up the CPU. > > > > > > Can you share your .config? > > > > Here you go... > > What version of gcc are you using? > > Can you post a disassembly of the first 10 instructions of > start_secondary()?
Pavel, ping? I'd like to try to get to the bottom of this issue soon. I asked for the gcc version and the disassembly of start_secondary() because I suspect gcc may have done a funky stack alignment prologue which copies the return address on the stack a second time after aligning it. -- Josh