misc: fastrpc: Skip reference for DMA handles

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commit 10df039834 upstream.

If multiple dma handles are passed with same fd over a remote call
the kernel driver takes a reference and expects that put for the
map will be called as many times to free the map. But DSP only
updates the fd one time in the fd list when the DSP refcount
goes to zero and hence kernel make put call only once for the
fd. This can cause SMMU fault issue as the same fd can be used
in future for some other call.

Fixes: 35a82b8713 ("misc: fastrpc: Add dma handle implementation")
Cc: stable@kernel.org
Co-developed-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Signed-off-by: Ling Xu <quic_lxu5@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://lore.kernel.org/r/20250912131236.303102-5-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Ling Xu 2025-09-12 14:12:36 +01:00 • committed by Greg Kroah-Hartman

parent c000f65f0a

commit f3f59bab68

1 changed files with 27 additions and 18 deletions

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drivers/misc/fastrpc.c

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