On Thu, Jan 11, 2018 at 02:00:27PM -0500, Vince Weaver wrote: > On Wed, 10 Jan 2018, Josh Poimboeuf wrote: > > > For the crash, you might try enabling CONFIG_DEBUG_ENTRY and seeing if > > that gives you any output. > > I did enable that, didn't seem to help on the haswell machien at least. > > > > > > WARNING: can't dereference iret registers at 000000000783fea8 for ip > > > > > paranoid_entry+0x2e/0x90 > > > > > WARNING: can't dereference registers at 00000000f0698d17 for ip > > > > > paranoid_entry+0x4c/0x90 > > > > > WARNING: stack going in the wrong direction? > > > > > ip=native_sched_clock+0x9/0x90 > > > > This all looks very weird. The stack pointers -- 000000000783fea8 and > > 00000000f0698d17 -- are obviously very wrong. I will try to recreate > > locally. > > On a related note, on a core2 machine with the perf_fuzzer I got this too: > > Jan 11 13:44:01 core2 kernel: [ 1078.931403] WARNING: stack recursion on > stack type 4 > Jan 11 13:44:01 core2 kernel: [ 1078.931411] WARNING: can't dereference > registers at 000000002c6beb99 for ip > swapgs_restore_regs_and_return_to_usermode+0x2b/0x7c
Yuck. This time it was stack recursion on the entry stack. In the previous error, recursion was detected on the IRQ stack. Otherwise they look quite similar. Was that also with nopti? I haven't had a chance to try it yet, any idea if these would be recreatable in a VM? -- Josh
