video: sm501fb: Early initialization of mm_lock mutex.
Commit 537a1bf059fa312355696fa6db80726e655e7f17 (fbdev: add mutex for
fb_mmap locking) introduces a ->mm_lock mutex for protecting smem
assignments. Unfortunately in the case of sm501fb these happen quite
early in the initialization code, well before the mutex_init() that takes
place in register_framebuffer(), leading to:
Badness at kernel/mutex.c:207
Pid : 1, Comm: swapper
CPU : 0 Not tainted (2.6.31-rc1-00284-g529ba0d-dirty #2273)
PC is at __mutex_lock_slowpath+0x72/0x1bc
PR is at __mutex_lock_slowpath+0x66/0x1bc
...
matroxfb appears to have the same issue and has solved it with an early
mutex_init(), so we do the same for sm501fb.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/sm501fb.c b/drivers/video/sm501fb.c
index 98f24f0..16d4f4c 100644
--- a/drivers/video/sm501fb.c
+++ b/drivers/video/sm501fb.c
@@ -1624,6 +1624,8 @@
if (!fbi)
return 0;
+ mutex_init(&info->fb[head]->mm_lock);
+
ret = sm501fb_init_fb(info->fb[head], head, drvname);
if (ret) {
dev_err(info->dev, "cannot initialise fb %s\n", drvname);
