kernel/linux.git/drivers/misc/fastrpc.c, branch v6.12.94

misc: fastrpc: Fix NULL pointer dereference in rpmsg callback

2026-06-19T11:42:32+00:00

commit 5401fb4fe10fac6134c308495df18ed74aebb9c4 upstream. A NULL pointer dereference was observed on Hawi at boot when the DSP sends a glink message before fastrpc_rpmsg_probe() has completed initialization: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000178 pc : _raw_spin_lock_irqsave+0x34/0x8c lr : fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] ... Call trace: _raw_spin_lock_irqsave+0x34/0x8c (P) fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] qcom_glink_native_rx+0x538/0x6a4 qcom_glink_smem_intr+0x14/0x24 [qcom_glink_smem] The faulting address 0x178 corresponds to the lock variable inside struct fastrpc_channel_ctx, confirming that cctx is NULL when fastrpc_rpmsg_callback() attempts to take the spinlock. There are two issues here. First, dev_set_drvdata() is called before spin_lock_init() and idr_init(), leaving a window where the callback can retrieve a valid cctx pointer but operate on an uninitialized spinlock. Second, the rpmsg channel becomes live as soon as the driver is bound, so fastrpc_rpmsg_callback() can fire before dev_set_drvdata() is called at all, resulting in dev_get_drvdata() returning NULL. Fix both issues by moving all cctx initialization ahead of dev_set_drvdata() so the structure is fully initialized before it becomes visible to the callback, and add a NULL check in fastrpc_rpmsg_callback() as a guard against any remaining window. Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model") Cc: stable@vger.kernel.org Signed-off-by: Mukesh Ojha Reviewed-by: Bjorn Andersson Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260530204528.116920-4-srini@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

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

2026-06-19T11:42:32+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 race in fastrpc_map_create

2026-06-19T11:42:32+00:00

commit 07ebe87915d8accdaba20c4f88c5ae430fe62fbb upstream. fastrpc_map_lookup returns a raw pointer after releasing fl->lock. The caller fastrpc_map_create then calls fastrpc_map_get (kref_get_unless_zero) on this unprotected pointer. A concurrent MEM_UNMAP can free the map between the lock release and the kref operation, resulting in a use-after-free on the freed slab object. Restore the take_ref parameter to fastrpc_map_lookup so the reference is acquired atomically under fl->lock before the pointer is exposed to the caller. Fixes: 10df039834f8 ("misc: fastrpc: Skip reference for DMA handles") Cc: stable@vger.kernel.org Signed-off-by: Zhenghang Xiao Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260530204528.116920-5-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

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

2026-06-19T11:42:32+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: check qcom_scm_assign_mem() return in rpmsg_probe

2026-04-18T08:41:56+00:00

[ Upstream commit 6a502776f4a4f80fb839b22f12aeaf0267fca344 ] In the SDSP probe path, qcom_scm_assign_mem() is used to assign the reserved memory to the configured VMIDs, but its return value was not checked. Fail the probe if the SCM call fails to avoid continuing with an unexpected/incorrect memory permission configuration. This issue was found by an in-house analysis workflow that extracts AST-based information and runs static checks, with LLM assistance for triage, and was confirmed by manual code review. No hardware testing was performed. Fixes: c3c0363bc72d4 ("misc: fastrpc: support complete DMA pool access to the DSP") Cc: stable@vger.kernel.org # 6.11-rc1 Signed-off-by: Xingjing Deng Reviewed-by: Dmitry Baryshkov Link: https://patch.msgid.link/20260131065539.2124047-1-xjdeng@buaa.edu.cn Signed-off-by: Greg Kroah-Hartman [ adapted qcom_scm_assign_mem() error check to use fdev_error label and rmem-based memory API ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: possible double-free of cctx->remote_heap

2026-04-11T12:24:49+00:00

commit ba2c83167b215da30fa2aae56b140198cf8d8408 upstream. fastrpc_init_create_static_process() may free cctx->remote_heap on the err_map path but does not clear the pointer. Later, fastrpc_rpmsg_remove() frees cctx->remote_heap again if it is non-NULL, which can lead to a double-free if the INIT_CREATE_STATIC ioctl hits the error path and the rpmsg device is subsequently removed/unbound. Clear cctx->remote_heap after freeing it in the error path to prevent the later cleanup from freeing it again. This issue was found by an in-house analysis workflow that extracts AST-based information and runs static checks, with LLM assistance for triage, and was confirmed by manual code review. No hardware testing was performed. Fixes: 0871561055e66 ("misc: fastrpc: Add support for audiopd") Cc: stable@vger.kernel.org # 6.2+ Signed-off-by: Xingjing Deng Reviewed-by: Dmitry Baryshkov Link: https://patch.msgid.link/20260129234140.410983-1-xjdeng@buaa.edu.cn Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Fix dma_buf object leak in fastrpc_map_lookup

2025-10-29T13:09:01+00:00

commit fff111bf45cbeeb659324316d68554e35d350092 upstream. In fastrpc_map_lookup, dma_buf_get is called to obtain a reference to the dma_buf for comparison purposes. However, this reference is never released when the function returns, leading to a dma_buf memory leak. Fix this by adding dma_buf_put before returning from the function, ensuring that the temporarily acquired reference is properly released regardless of whether a matching map is found. Fixes: 9031626ade38 ("misc: fastrpc: Fix fastrpc_map_lookup operation") Cc: stable@kernel.org Signed-off-by: Junhao Xie Tested-by: Xilin Wu Link: https://lore.kernel.org/stable/48B368FB4C7007A7%2B20251017083906.3259343-1-bigfoot%40radxa.com Link: https://patch.msgid.link/48B368FB4C7007A7+20251017083906.3259343-1-bigfoot@radxa.com Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Skip reference for DMA handles

2025-10-15T10:00:23+00:00

commit 10df039834f84a297c72ec962c0f9b7c8c5ca31a 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: 35a82b87135d ("misc: fastrpc: Add dma handle implementation") Cc: stable@kernel.org Co-developed-by: Ekansh Gupta Signed-off-by: Ekansh Gupta Signed-off-by: Ling Xu Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20250912131236.303102-5-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: fix possible map leak in fastrpc_put_args

2025-10-15T10:00:23+00:00

commit da1ba64176e0138f2bfa96f9e43e8c3640d01e1e upstream. copy_to_user() failure would cause an early return without cleaning up the fdlist, which has been updated by the DSP. This could lead to map leak. Fix this by redirecting to a cleanup path on failure, ensuring that all mapped buffers are properly released before returning. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable@kernel.org Co-developed-by: Ekansh Gupta Signed-off-by: Ekansh Gupta Signed-off-by: Ling Xu Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20250912131236.303102-4-srini@kernel.org Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Fix fastrpc_map_lookup operation

2025-10-15T10:00:23+00:00

commit 9031626ade38b092b72638dfe0c6ffce8d8acd43 upstream. Fastrpc driver creates maps for user allocated fd buffers. Before creating a new map, the map list is checked for any already existing maps using map fd. Checking with just map fd is not sufficient as the user can pass offsetted buffer with less size when the map is created and then a larger size the next time which could result in memory issues. Check for dma_buf object also when looking up for the map. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: stable@kernel.org Co-developed-by: Ekansh Gupta Signed-off-by: Ekansh Gupta Signed-off-by: Ling Xu Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20250912131236.303102-3-srini@kernel.org Signed-off-by: Greg Kroah-Hartman