udmabuf: fix memory leak on last export_udmabuf() error path

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[ Upstream commit f49856f525 ]

In export_udmabuf(), if dma_buf_fd() fails because the FD table is full, a
dma_buf owning the udmabuf has already been created; but the error handling
in udmabuf_create() will tear down the udmabuf without doing anything about
the containing dma_buf.

This leaves a dma_buf in memory that contains a dangling pointer; though
that doesn't seem to lead to anything bad except a memory leak.

Fix it by moving the dma_buf_fd() call out of export_udmabuf() so that we
can give it different error handling.

Note that the shape of this code changed a lot in commit 5e72b2b41a
("udmabuf: convert udmabuf driver to use folios"); but the memory leak
seems to have existed since the introduction of udmabuf.

Fixes: fbb0de7950 ("Add udmabuf misc device")
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241204-udmabuf-fixes-v2-3-23887289de1c@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Jann Horn 2024-12-04 17:26:21 +01:00 • committed by Greg Kroah-Hartman

parent 8e86e9909a

commit c9fc8428d4

1 changed files with 17 additions and 11 deletions

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drivers/dma-buf/udmabuf.c

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