[PATCH] pstore: do not use message compression without lock

[Konstantin Khlebnikov <khlebnikov@yandex-team.ru>]

pstore_compress() uses static stream buffer for zlib-deflate which
easily crashes when several concurrent threads use one shared state.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 fs/pstore/platform.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index c4c9a10c5760..de525ec0b490 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -299,7 +299,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		bool compressed;
 		size_t total_len;
 
-		if (big_oops_buf) {
+		if (big_oops_buf && is_locked) {
 			dst = big_oops_buf;
 			hsize = sprintf(dst, "%s#%d Part%u\n", why,
 							oopscount, part);