Ingo Molnar <mi...@kernel.org> writes: > * Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > >> Vitaly Kuznetsov <vkuzn...@redhat.com> writes: >> >> > A hang on CPU0 onlining after a preceding offlining is observed. Trace >> > shows that CPU0 is stuck in check_tsc_sync_target() waiting for source >> > CPU to run check_tsc_sync_source() but this never happens. Source CPU, >> > in its turn, is stuck on synchronize_sched() which is called from >> > native_cpu_up() -> do_boot_cpu() -> unregister_nmi_handler(). >> > >> > Fix the issue by moving unregister_nmi_handler() from do_boot_cpu() to >> > native_cpu_up() after cpu onlining is done. > > Looks like a classic ABBA deadlock, due to the use of synchronize_sched() in > unregister_nmi_handler(), right? >
Exactly. >> > >> > Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> >> > --- >> > It's been awile since my v1 submission, no comments so far. Resending. >> >> Sorry, but >> >> ping? >> >> I haven't received a single comment on this since the initial submission >> on June, 26 - is it so bad? :-) > > So the fix looks good to me at first sight, but wanted to wait for Thomas to > ack > it - once he gets back from vacation. > Thanks! -- Vitaly
