On Tue, Mar 16, 2021 at 5:03 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Tue, Mar 16, 2021 at 4:51 PM Russell King - ARM Linux admin > <linux@xxxxxxxxxxxxxxx> wrote: > > On Tue, Mar 16, 2021 at 04:44:45PM +0100, Arnd Bergmann wrote: > > > On Tue, Mar 16, 2021 at 11:17 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > > > The compiler is gcc version 10.2.1 20210110 (Debian 10.2.1-6) > > > > > > Ok, building with Ubuntu 10.2.1-1ubuntu1 20201207 locally, that's > > > the closest I have installed, and I think the Debian and Ubuntu versions > > > are generally quite close in case of gcc since they are maintained by > > > the same packagers. > > > > ... which shouldn't be a problem - that's just over 1/4 of the stack > > space. Could it be the syzbot's gcc is doing something weird and > > inflating the stack frames? > > It's possible, I think that's really unlikely given that it's just Debian's > gcc, which is as close to mainline as the version I was using. > > Uwe's DEBUG_STACKOVERFLOW patch from a while ago might > help if this was the problem though: > https://lore.kernel.org/linux-arm-kernel/20200108082913.29710-1-u.kleine-koenig@xxxxxxxxxxxxxx/ > > My best guess is something going wrong in the interrupt > that triggered the preempt_schedule() which ended up calling > task_stack_end_corrupted() in schedule_debug(), as you suggested > earlier. FWIW I see slightly larger frames with the config: 073ab64 <ima_calc_field_array_hash_tfm>: 8073ab64: e1a0c00d mov ip, sp 8073ab68: e92ddff0 push {r4, r5, r6, r7, r8, r9, sl, fp, ip, lr, pc} 8073ab6c: e24cb004 sub fp, ip, #4 8073ab70: e24ddfa7 sub sp, sp, #668 ; 0x29c page_alloc can also do reclaim, I had the impression that reclaim can be quite heavy-weight in all respects.
