If function_graph tracer is enabled during kexec, we see the below
exception in the simulator:
root@(none):/# kexec -e
kvm: exiting hardware virtualization
kexec_core: Starting new kernel
[ 19.262020070,5] OPAL: Switch to big-endian OS
kexec: Starting switchover sequence.
Interrupt to 0xC000000000004380 from 0xC000000000004380
** Execution stopped: Continuous Interrupt, Instruction caused
exception, **
Now that we have a more effective way to completely disable ftrace on
ppc64, let's also use that before switching to a new kernel during
kexec.
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
arch/powerpc/kernel/machine_kexec.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kernel/machine_kexec.c
b/arch/powerpc/kernel/machine_kexec.c
index 2694d078741d..936c7e2d421e 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -98,12 +98,14 @@ void machine_kexec(struct kimage *image)
int save_ftrace_enabled;
save_ftrace_enabled = __ftrace_enabled_save();
+ this_cpu_disable_ftrace();
if (ppc_md.machine_kexec)
ppc_md.machine_kexec(image);
else
default_machine_kexec(image);
+ this_cpu_enable_ftrace();
__ftrace_enabled_restore(save_ftrace_enabled);
/* Fall back to normal restart if we're still alive. */
--
2.16.2
