Hi Russell, On Wed, 9 Mar 2022 at 20:37, Russell King (Oracle) <linux@xxxxxxxxxxxxxxx> wrote: > > On Wed, Mar 09, 2022 at 03:57:32PM +0100, Ard Biesheuvel wrote: > > On Wed, 9 Mar 2022 at 15:44, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote: > > > <trim> > Well, we unwound until: > > __irq_svc from migrate_disable+0x0/0x70 > > and then crashed - and the key thing there is that we're at the start > of migrate_disable() when we took an interrupt. > > For some reason, this triggers an access to address 0x10, which faults. > We then try unwinding again, and successfully unwind all the way back > to the same point (the line above) which then causes the unwinder to > again access address 0x10, and the cycle repeats with the stack > growing bigger and bigger. > > I'd suggest also testing without the revert but with my patch. I have tested your patch on top of linux next-20220309 and still see kernel crash as below [1]. build link [2]. [ 26.812060] 8<--- cut here --- [ 26.813459] Unhandled fault: page domain fault (0x01b) at 0xb6a3ab70 [ 26.816139] [b6a3ab70] *pgd=fb28a835 [ 26.817770] Internal error: : 1b [#1] SMP ARM [ 26.819636] Modules linked in: [ 26.820956] CPU: 0 PID: 211 Comm: haveged Not tainted 5.17.0-rc7-next-20220309 #1 [ 26.824519] Hardware name: Generic DT based system [ 26.827148] PC is at __read_once_word_nocheck+0x0/0x8 [ 26.829856] LR is at unwind_frame+0x7dc/0xab4 - Naresh [1] https://lkft.validation.linaro.org/scheduler/job/4688599#L596 [2] https://builds.tuxbuild.com/269gYLGuAdmltuLhIUDAjS2fg1Q/
