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Commit f50bf2b2f5e83b794e0bdb2f3f589f55ef0d52d0

Authored by Paul Mundt
Committed by Linus Torvalds
1 parent de481ba925
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 1 changed file with 2 additions and 0 deletions Side-by-side Diff

drivers/video/sm501fb.c
Diff comments   View file @ f50bf2b
... ... @@ -1624,6 +1624,8 @@
1624 1624 if (!fbi)
1625 1625 return 0;
1626 1626  
  1627 + mutex_init(&info->fb[head]->mm_lock);
  1628 +
1627 1629 ret = sm501fb_init_fb(info->fb[head], head, drvname);
1628 1630 if (ret) {
1629 1631 dev_err(info->dev, "cannot initialise fb %s\n", drvname);