On Thu, Nov 23, 2017 at 4:32 AM, Mahesh J Salgaonkar <mah...@linux.vnet.ibm.com> wrote: > From: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> > > Rebooting into a new kernel with kexec fails in trace_tlbie() which is > called from native_hpte_clear(). This happens if the running kernel has > CONFIG_LOCKDEP enabled. With lockdep enabled, the tracepoints always > execute few RCU checks regardless of whether tracing is on or off. > We are already in the last phase of kexec sequence in real mode with > HILE_BE set. At this point the RCU check ends up in RCU_LOCKDEP_WARN and > causes kexec to fail. >
Effectively we can't enter the trace point code after we've set HILE_BE. Do we need a fixes tag? Or is this a side-effect of a new generic change? I think the right thing in the longer run might be to do a TRACE_EVENT_CONDITION and have the condition do the right thing, but what you have for now is good. Balbir Singh.
