powerpc/pseries: Initialise nvram_pstore_info's buf_lock

nvram_pstore_info's buf_lock is not initialized before registering,
which is clearly incorrect.

It causes some strange behavior when trying to obtain the lock during
kdump process.

On a UP configuration, the console stopped for a couple of seconds, then
"lockup suspected" warning printed out, but then it continued to run.

So try lock fails, and lockup reported, but then arch_spin_lock()
passes.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
[mpe: Edited changelog]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index 11a3b617ef5d..054a0ed5c7ee 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -715,6 +715,8 @@ static int nvram_pstore_init(void)
         nvram_pstore_info.buf = oops_data;
         nvram_pstore_info.bufsize = oops_data_sz;
 
+        spin_lock_init(&nvram_pstore_info.buf_lock);
+
         rc = pstore_register(&nvram_pstore_info);
         if (rc != 0)
                 pr_err("nvram: pstore_register() failed, defaults to "