Re: powernv: Avoid calling trace tlbie in kexec path.

On Wed, 2017-11-22 at 17:32:07 UTC, Mahesh J Salgaonkar wrote:

From: Mahesh Salgaonkar <redacted>

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.

Fix this by not calling trace_tlbie() from native_hpte_clear().

Signed-off-by: Mahesh Salgaonkar <redacted>
Reported-by: Aneesh Kumar K.V <redacted>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Naveen N. Rao <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/a3961f824cdbe7eb431254dc7d8f6f

cheers