Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH] clocksource: hyper-v: unexport __init-annotated hv_init_clocksource() | Date | Mon, 06 Jun 2022 08:59:48 +0200 |
| |
Masahiro Yamada <masahiroy@kernel.org> writes:
> EXPORT_SYMBOL and __init is a bad combination because the .init.text > section is freed up after the initialization. Hence, modules cannot > use symbols annotated __init. The access to a freed symbol may end up > with kernel panic. > > modpost used to detect it, but it has been broken for a decade. > > Recently, I fixed modpost so it started to warn it again, then this > showed up in linux-next builds. > > There are two ways to fix it: > > - Remove __init > - Remove EXPORT_SYMBOL > > I chose the latter for this case because the only in-tree call-site, > arch/x86/kernel/cpu/mshyperv.c is never compiled as modular. > (CONFIG_HYPERVISOR_GUEST is boolean) > > Fixes: dd2cb348613b ("clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic") > Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > drivers/clocksource/hyperv_timer.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c > index ff188ab68496..bb47610bbd1c 100644 > --- a/drivers/clocksource/hyperv_timer.c > +++ b/drivers/clocksource/hyperv_timer.c > @@ -565,4 +565,3 @@ void __init hv_init_clocksource(void) > hv_sched_clock_offset = hv_read_reference_counter(); > hv_setup_sched_clock(read_hv_sched_clock_msr); > } > -EXPORT_SYMBOL_GPL(hv_init_clocksource);
hv_init_clocksource() is not called from modules indeed,
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
-- Vitaly
| |