kernel/linux.git/drivers/misc/fastrpc.c, branch v5.15.210

misc: fastrpc: fix DMA address corruption due to find_vma misuse

2026-06-19T11:33:38+00:00

commit 464c6ad2aa16e1e1df9d559289199356493d1e00 upstream. fastrpc_get_args() uses find_vma() to look up the VMA for a user-provided pointer and compute a DMA address offset. When the address falls in a gap before the returned VMA, (ptr & PAGE_MASK) - vma->vm_start underflows, corrupting the DMA address sent to the DSP. Replace find_vma() with vma_lookup(), which returns NULL when the address is not contained within any VMA. Cc: stable@vger.kernel.org Fixes: 80f3afd72bd4 ("misc: fastrpc: consider address offset before sending to DSP") Reported-by: Yuhao Jiang Signed-off-by: Junrui Luo Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260530204528.116920-3-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context

2026-06-19T11:33:38+00:00

commit e85eb5feca8e254905ffa6c57a3c99c89a674a0f upstream. There is a race between fastrpc_device_release() and the workqueue that processes DSP responses. When the user closes the file descriptor, fastrpc_device_release() frees the fastrpc_user structure. Concurrently, an in-flight DSP invocation can complete and fastrpc_rpmsg_callback() schedules context cleanup via schedule_work(&ctx->put_work). If the workqueue runs fastrpc_context_free() in parallel with or after fastrpc_device_release() has freed the user structure, it dereferences the freed fastrpc_user. Depending on the state of the context at the time of the race, any one of the following accesses can be hit: 1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...) to strip the SID bits from the stored IOVA before passing the physical address to dma_free_coherent(). 2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to reconstruct the source permission bitmask needed for the qcom_scm_assign_mem() call that returns memory from the DSP VM back to HLOS. 3. fastrpc_free_map() acquires map->fl->lock to safely remove the map node from the fl->maps list. The resulting use-after-free manifests as: pc : fastrpc_buf_free+0x38/0x80 [fastrpc] lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_put_wq+0x78/0xa0 [fastrpc] process_one_work+0x180/0x450 worker_thread+0x26c/0x388 Add kref-based reference counting to fastrpc_user. Have each invoke context take a reference on the user at allocation time and release it when the context is freed. Release the initial reference in fastrpc_device_release() at file close. Move the teardown of the user structure — freeing pending contexts, maps, mmaps, and the channel context reference — into the kref release callback fastrpc_user_free(), so that it runs only when the last reference is dropped, regardless of whether that happens at device close or after the final in-flight context completes. Fixes: 6cffd79504ce ("misc: fastrpc: Add support for dmabuf exporter") Cc: stable@kernel.org Signed-off-by: Anandu Krishnan E Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260530204528.116920-2-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Fix registered buffer page address

2025-03-13T11:50:33+00:00

commit 6ca4ea1f88a06a04ed7b2c9c6bf9f00833b68214 upstream. For registered buffers, fastrpc driver sends the buffer information to remote subsystem. There is a problem with current implementation where the page address is being sent with an offset leading to improper buffer address on DSP. This is leads to functional failures as DSP expects base address in page information and extracts offset information from remote arguments. Mask the offset and pass the base page address to DSP. This issue is observed is a corner case when some buffer which is registered with fastrpc framework is passed with some offset by user and then the DSP implementation tried to read the data. As DSP expects base address and takes care of offsetting with remote arguments, passing an offsetted address will result in some unexpected data read in DSP. All generic usecases usually pass the buffer as it is hence is problem is not usually observed. If someone tries to pass offsetted buffer and then tries to compare data at HLOS and DSP end, then the ambiguity will be observed. Fixes: 80f3afd72bd4 ("misc: fastrpc: consider address offset before sending to DSP") Cc: stable@kernel.org Signed-off-by: Ekansh Gupta Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20250110134239.123603-3-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Mark all sessions as invalid in cb_remove

2024-02-23T07:55:06+00:00

commit a4e61de63e34860c36a71d1a364edba16fb6203b upstream. In remoteproc shutdown sequence, rpmsg_remove will get called which would depopulate all the child nodes that have been created during rpmsg_probe. This would result in cb_remove call for all the context banks for the remoteproc. In cb_remove function, session 0 is getting skipped which is not correct as session 0 will never become available again. Add changes to mark session 0 also as invalid. Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model") Cc: stable Signed-off-by: Ekansh Gupta Link: https://lore.kernel.org/r/20240108114833.20480-1-quic_ekangupt@quicinc.com Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Clean buffers on remote invocation failures

2023-11-08T16:26:41+00:00

commit 1c8093591d1e372d700fe65423e7315a8ecf721b upstream. With current design, buffers and dma handles are not freed in case of remote invocation failures returned from DSP. This could result in buffer leakings and dma handle pointing to wrong memory in the fastrpc kernel. Adding changes to clean buffers and dma handles even when remote invocation to DSP returns failures. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable Signed-off-by: Ekansh Gupta Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231013122007.174464-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Create fastrpc scalar with correct buffer count

2023-07-23T11:47:47+00:00

commit 0b4e32df3e09406b835d8230b9331273f2805058 upstream. A process can spawn a PD on DSP with some attributes that can be associated with the PD during spawn and run. The invocation corresponding to the create request with attributes has total 4 buffers at the DSP side implementation. If this number is not correct, the invocation is expected to fail on DSP. Added change to use correct number of buffer count for creating fastrpc scalar. Fixes: d73f71c7c6ee ("misc: fastrpc: Add support for create remote init process") Cc: stable Tested-by: Ekansh Gupta Signed-off-by: Ekansh Gupta Message-ID: <1686743685-21715-1-git-send-email-quic_ekangupt@quicinc.com> Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: reject new invocations during device removal

2023-06-09T08:32:29+00:00

commit 46248400d81e2aa0b65cd659d6f40188192a58b6 upstream. The channel's rpmsg object allows new invocations to be made. After old invocations are already interrupted, the driver shouldn't try to invoke anymore. Invalidating the rpmsg at the end of the driver removal function makes it easy to cause a race condition in userspace. Even closing a file descriptor before the driver finishes its cleanup can cause an invocation via fastrpc_release_current_dsp_process() and subsequent timeout. Invalidate the channel before the invocations are interrupted to make sure that no invocations can be created to hang after the device closes. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable Signed-off-by: Richard Acayan Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20230523152550.438363-5-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: return -EPIPE to invocations on device removal

2023-06-09T08:32:29+00:00

commit b6a062853ddf6b4f653af2d8b75ba45bb9a036ad upstream. The return value is initialized as -1, or -EPERM. The completion of an invocation implies that the return value is set appropriately, but "Permission denied" does not accurately describe the outcome of the invocation. Set the invocation's return value to a more appropriate "Broken pipe", as the cleanup breaks the driver's connection with rpmsg. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable Signed-off-by: Richard Acayan Reviewed-by: Srinivas Kandagatla Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20230523152550.438363-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Fix use-after-free race condition for maps

2023-01-24T06:22:45+00:00

commit 96b328d119eca7563c1edcc4e1039a62e6370ecb upstream. It is possible that in between calling fastrpc_map_get() until map->fl->lock is taken in fastrpc_free_map(), another thread can call fastrpc_map_lookup() and get a reference to a map that is about to be deleted. Rewrite fastrpc_map_get() to only increase the reference count of a map if it's non-zero. Propagate this to callers so they can know if a map is about to be deleted. Fixes this warning: refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 10100 at lib/refcount.c:25 refcount_warn_saturate ... Call trace: refcount_warn_saturate [fastrpc_map_get inlined] [fastrpc_map_lookup inlined] fastrpc_map_create fastrpc_internal_invoke fastrpc_device_ioctl __arm64_sys_ioctl invoke_syscall Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20221124174941.418450-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Don't remove map on creater_process and device_release

2023-01-24T06:22:45+00:00

commit 5bb96c8f9268e2fdb0e5321cbc358ee5941efc15 upstream. Do not remove the map from the list on error path in fastrpc_init_create_process, instead call fastrpc_map_put, to avoid use-after-free. Do not remove it on fastrpc_device_release either, call fastrpc_map_put instead. The fastrpc_free_map is the only proper place to remove the map. This is called only after the reference count is 0. Fixes: b49f6d83e290 ("misc: fastrpc: Fix a possible double free") Cc: stable Co-developed-by: Ola Jeppsson Signed-off-by: Ola Jeppsson Signed-off-by: Abel Vesa Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20221124174941.418450-3-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman