diff options
| author | Andrea Righi <righi.andrea@gmail.com> | 2009-02-04 15:12:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-02-05 12:56:46 -0800 |
| commit | 1f5e31d7e55ac7fbd4ec5e5b20c8868b0e4564c9 (patch) | |
| tree | 713d0ace63c95da9b989aafce8ec84ebb1d1cbc3 /drivers/video/fbcmap.c | |
| parent | afd8d0f940ba5078f38e435440089117ac7d9eb4 (diff) | |
fbmem: don't call copy_from/to_user() with mutex held
Avoid calling copy_from/to_user() with fb_info->lock mutex held in fbmem
ioctl().
fb_mmap() is called under mm->mmap_sem (A) held, that also acquires
fb_info->lock (B); fb_ioctl() takes fb_info->lock (B) and does
copy_from/to_user() that might acquire mm->mmap_sem (A), causing a
deadlock.
NOTE: it doesn't push down the fb_info->lock in each own driver's
fb_ioctl(), so there are still potential deadlocks elsewhere.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Johannes Weiner <hannes@saeurebad.de>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/fbcmap.c')
| -rw-r--r-- | drivers/video/fbcmap.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/drivers/video/fbcmap.c b/drivers/video/fbcmap.c index 91b78e691505..f53b9f1d6aba 100644 --- a/drivers/video/fbcmap.c +++ b/drivers/video/fbcmap.c @@ -250,10 +250,6 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info) int rc, size = cmap->len * sizeof(u16); struct fb_cmap umap; - if (cmap->start < 0 || (!info->fbops->fb_setcolreg && - !info->fbops->fb_setcmap)) - return -EINVAL; - memset(&umap, 0, sizeof(struct fb_cmap)); rc = fb_alloc_cmap(&umap, cmap->len, cmap->transp != NULL); if (rc) @@ -262,11 +258,23 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info) copy_from_user(umap.green, cmap->green, size) || copy_from_user(umap.blue, cmap->blue, size) || (cmap->transp && copy_from_user(umap.transp, cmap->transp, size))) { - fb_dealloc_cmap(&umap); - return -EFAULT; + rc = -EFAULT; + goto out; } umap.start = cmap->start; + if (!lock_fb_info(info)) { + rc = -ENODEV; + goto out; + } + if (cmap->start < 0 || (!info->fbops->fb_setcolreg && + !info->fbops->fb_setcmap)) { + rc = -EINVAL; + goto out1; + } rc = fb_set_cmap(&umap, info); +out1: + unlock_fb_info(info); +out: fb_dealloc_cmap(&umap); return rc; } |