Mahesh J Salgaonkar <mah...@linux.vnet.ibm.com> writes: > From: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> > > machine_check_early() gets called in real mode. The very first time when > add_taint() is called, it prints a warning which ends up calling opal > call (that uses OPAL_CALL wrapper) for writing it to console. If we get a > very first machine check while we are in opal we are doomed. OPAL_CALL > overwrites the PACASAVEDMSR in r13 and in this case when we are done with > MCE handling the original opal call will use this new MSR on it's way > back to opal_return. This usually leads unexpected behaviour or kernel > to panic. Instead use the add_taint_no_warn() that does not call printk. > > This is broken with current FW level. We got lucky so far for not getting > very first MCE hit while in OPAL. But easily reproducible on Mambo. > This should go to stable as well alongwith patch 1/2.
This is not a good way to fix a bug that needs to go back to stable. Changing generic code means I need to sync up with the right maintainer, get acks, etc. And then convince people that it should go to stable also. So you can please fix this a different way for stable? Can we just do the tainting later, once we're in virtual mode? cheers > Fixes: 27ea2c420cad powerpc: Set the correct kernel taint on machine check > errors. > Signed-off-by: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/traps.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > index 62b587f..4a048dc 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -306,7 +306,7 @@ long machine_check_early(struct pt_regs *regs) > > __this_cpu_inc(irq_stat.mce_exceptions); > > - add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); > + add_taint_no_warn(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); > > /* > * See if platform is capable of handling machine check. (e.g. PowerNV
