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* [PATCH AUTOSEL 5.15 001/146] dma-buf: WARN on dmabuf release with pending attachments
@ 2021-11-08 17:42 Sasha Levin
  2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 038/146] media: mt9p031: Fix corrupted frame after restarting stream Sasha Levin
                   ` (11 more replies)
  0 siblings, 12 replies; 16+ messages in thread
From: Sasha Levin @ 2021-11-08 17:42 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Charan Teja Reddy, Christian König, Sasha Levin,
	sumit.semwal, linux-media, dri-devel, linaro-mm-sig

From: Charan Teja Reddy <charante@codeaurora.org>

[ Upstream commit f492283b157053e9555787262f058ae33096f568 ]

It is expected from the clients to follow the below steps on an imported
dmabuf fd:
a) dmabuf = dma_buf_get(fd) // Get the dmabuf from fd
b) dma_buf_attach(dmabuf); // Clients attach to the dmabuf
   o Here the kernel does some slab allocations, say for
dma_buf_attachment and may be some other slab allocation in the
dmabuf->ops->attach().
c) Client may need to do dma_buf_map_attachment().
d) Accordingly dma_buf_unmap_attachment() should be called.
e) dma_buf_detach () // Clients detach to the dmabuf.
   o Here the slab allocations made in b) are freed.
f) dma_buf_put(dmabuf) // Can free the dmabuf if it is the last
reference.

Now say an erroneous client failed at step c) above thus it directly
called dma_buf_put(), step f) above. Considering that it may be the last
reference to the dmabuf, buffer will be freed with pending attachments
left to the dmabuf which can show up as the 'memory leak'. This should
at least be reported as the WARN().

Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1627043468-16381-1-git-send-email-charante@codeaurora.org
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma-buf/dma-buf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 63d32261b63ff..474de2d988ca7 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -82,6 +82,7 @@ static void dma_buf_release(struct dentry *dentry)
 	if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
 		dma_resv_fini(dmabuf->resv);
 
+	WARN_ON(!list_empty(&dmabuf->attachments));
 	module_put(dmabuf->owner);
 	kfree(dmabuf->name);
 	kfree(dmabuf);
-- 
2.33.0


^ permalink raw reply related	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2021-11-14 14:26 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-11-08 17:42 [PATCH AUTOSEL 5.15 001/146] dma-buf: WARN on dmabuf release with pending attachments Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 038/146] media: mt9p031: Fix corrupted frame after restarting stream Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 039/146] media: netup_unidvb: handle interrupt properly according to the firmware Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 040/146] media: atomisp: Fix error handling in probe Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 041/146] media: stm32: Potential NULL pointer dereference in dcmi_irq_thread() Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 042/146] media: uvcvideo: Set capability in s_param Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 043/146] media: uvcvideo: Return -EIO for control errors Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 044/146] media: uvcvideo: Set unique vdev name based in type Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 045/146] media: vidtv: Fix memory leak in remove Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 046/146] media: s5p-mfc: fix possible null-pointer dereference in s5p_mfc_probe() Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 047/146] media: s5p-mfc: Add checking to s5p_mfc_probe() Sasha Levin
2021-11-08 17:43 ` [PATCH AUTOSEL 5.15 048/146] media: videobuf2: rework vb2_mem_ops API Sasha Levin
2021-11-09  7:54 ` AUTOSEL series truncated was -- Re: [PATCH AUTOSEL 5.15 001/146] dma-buf: WARN on dmabuf release with pending attachments Pavel Machek
2021-11-09  8:07   ` Christian König
2021-11-09 16:05   ` Randy Dunlap
2021-11-14 14:25     ` Sasha Levin

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