From 81b2dbcad86732ffc02bad87aa25c4651199fc77 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Tue, 20 May 2008 09:53:52 -0700 Subject: [PATCH] Fix a deadlock in the bttv driver 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 Reported-by: Koos Vriezen Signed-off-by: Arjan van de Ven Signed-off-by: Linus Torvalds --- 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(-) diff --git a/drivers/media/video/bt8xx/bttv-driver.c b/drivers/media/video/bt8xx/bttv-driver.c index 2ca3e9cfb2b..0165aac533b 100644 --- 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, void *priv, struct video_mbuf *mbuf) 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); diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c index 982f4463896..0a88c44ace0 100644 --- a/drivers/media/video/videobuf-core.c +++ b/drivers/media/video/videobuf-core.c @@ -331,7 +331,7 @@ int videobuf_mmap_free(struct videobuf_queue *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) { @@ -1129,6 +1129,7 @@ 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); diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h index 5b39a22533f..874f1340d04 100644 --- a/include/media/videobuf-core.h +++ b/include/media/videobuf-core.h @@ -237,6 +237,9 @@ unsigned int videobuf_poll_stream(struct file *file, 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); -- 2.41.0