]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
dma-buf: fix UAF in dma_buf_put() tracepoint
authorAndi Shyti <andi.shyti@kernel.org>
Wed, 8 Apr 2026 12:39:15 +0000 (14:39 +0200)
committerChristian König <christian.koenig@amd.com>
Mon, 13 Apr 2026 13:59:22 +0000 (15:59 +0200)
commit2d76319c4cbb19eccfca71fa05d40a6b4ce7fc3d
treea1d3e1b417133b779b71b820017b69af88228450
parenteecdd4bd6e47bf0c8ff1e049771fa5bab7074c7c
dma-buf: fix UAF in dma_buf_put() tracepoint

dma_buf_put() may drop the final file reference via fput(), which
can free the dma-buf. The new tracepoint invocation was added
after fput(), and DMA_BUF_TRACE() dereferences dmabuf and takes
dmabuf->name_lock.

This leads to a use-after-free on the final put, visible for
example as a spinlock bad magic fault on a poisoned 0x6b6b6b...
lock.

Move the dma_buf_put tracepoint before fput().

Reported-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Fixes: 281a22631423 ("dma-buf: add some tracepoints to debug.")
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260408123916.2604101-1-andi.shyti@kernel.org
drivers/dma-buf/dma-buf.c