From: Jérôme Glisse jglisse@redhat.com

The debugfs take reference on fence without dropping them. Also the rcu section are not well balance. Fix all that ...

Changed since v1: - moved fobj logic around to be rcu safe

Signed-off-by: Jérôme Glisse jglisse@redhat.com Cc: Christian König christian.koenig@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Sumit Semwal sumit.semwal@linaro.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: Stéphane Marchesin marcheu@chromium.org Cc: stable@vger.kernel.org --- drivers/dma-buf/dma-buf.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 13884474d158..9688d99894d6 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1048,27 +1048,38 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) while (true) { seq = read_seqcount_begin(&robj->seq); rcu_read_lock(); - fobj = rcu_dereference(robj->fence); - shared_count = fobj ? fobj->shared_count : 0; fence = rcu_dereference(robj->fence_excl); + fence = dma_fence_get_rcu(fence); if (!read_seqcount_retry(&robj->seq, seq)) break; rcu_read_unlock(); } - - if (fence) + if (fence) { seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); - for (i = 0; i < shared_count; i++) { + dma_fence_put(fence); + } + + rcu_read_lock(); + fobj = rcu_dereference(robj->fence); + shared_count = fobj ? fobj->shared_count : 0; + for (i = 0, fence = NULL; i < shared_count; i++) { fence = rcu_dereference(fobj->shared[i]); if (!dma_fence_get_rcu(fence)) continue; + rcu_read_unlock(); + seq_printf(s, "\tShared fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); + dma_fence_put(fence); + + rcu_read_lock(); + fobj = rcu_dereference(robj->fence); + shared_count = fobj ? fobj->shared_count : 0; } rcu_read_unlock();