Messages in this thread Patch in this message | | | Date | Fri, 13 Jun 2008 17:12:18 -0700 | From | Greg KH <> | Subject | [patch 45/47] bttv: Fix a deadlock in the bttv driver |
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-stable review patch. If anyone has any objections, please let us know.
------------------ From: Arjan van de Ven <arjan@linux.intel.com>
commit 81b2dbcad86732ffc02bad87aa25c4651199fc77 in mainline.
vidiocgmbuf() does this: mutex_lock(&fh->cap.vb_lock); retval = videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize, V4L2_MEMORY_MMAP);
and videobuf_mmap_setup() then just does mutex_lock(&q->vb_lock); ret = __videobuf_mmap_setup(q, bcount, bsize, memory); mutex_unlock(&q->vb_lock);
which is an obvious double-take deadlock.
This patch fixes this by having vidiocgmbuf() just call the __videobuf_mmap_setup function instead.
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org> Reported-by: Koos Vriezen <koos.vriezen@gmail.com> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/media/video/bt8xx/bttv-driver.c | 2 +- drivers/media/video/videobuf-core.c | 3 ++- include/media/videobuf-core.h | 3 +++ 3 files changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/media/video/bt8xx/bttv-driver.c +++ b/drivers/media/video/bt8xx/bttv-driver.c @@ -2613,7 +2613,7 @@ static int vidiocgmbuf(struct file *file struct bttv_fh *fh = priv; mutex_lock(&fh->cap.vb_lock); - retval = videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize, + retval = __videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize, V4L2_MEMORY_MMAP); if (retval < 0) { mutex_unlock(&fh->cap.vb_lock); --- a/drivers/media/video/videobuf-core.c +++ b/drivers/media/video/videobuf-core.c @@ -335,7 +335,7 @@ int videobuf_mmap_free(struct videobuf_q } /* Locking: Caller holds q->vb_lock */ -static int __videobuf_mmap_setup(struct videobuf_queue *q, +int __videobuf_mmap_setup(struct videobuf_queue *q, unsigned int bcount, unsigned int bsize, enum v4l2_memory memory) { @@ -1093,6 +1093,7 @@ EXPORT_SYMBOL_GPL(videobuf_read_stream); EXPORT_SYMBOL_GPL(videobuf_read_one); EXPORT_SYMBOL_GPL(videobuf_poll_stream); +EXPORT_SYMBOL_GPL(__videobuf_mmap_setup); EXPORT_SYMBOL_GPL(videobuf_mmap_setup); EXPORT_SYMBOL_GPL(videobuf_mmap_free); EXPORT_SYMBOL_GPL(videobuf_mmap_mapper); --- a/include/media/videobuf-core.h +++ b/include/media/videobuf-core.h @@ -227,6 +227,9 @@ unsigned int videobuf_poll_stream(struct int videobuf_mmap_setup(struct videobuf_queue *q, unsigned int bcount, unsigned int bsize, enum v4l2_memory memory); +int __videobuf_mmap_setup(struct videobuf_queue *q, + unsigned int bcount, unsigned int bsize, + enum v4l2_memory memory); int videobuf_mmap_free(struct videobuf_queue *q); int videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma); --
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