kernel/linux.git/drivers/misc/fastrpc.c, branch linux-7.1.y

misc: fastrpc: fix use-after-free race in fastrpc_map_create

2026-06-05T15:20:51+00:00

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 NULL pointer dereference in rpmsg callback

2026-06-05T15:20:51+00:00

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

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

2026-06-05T15:20:50+00:00

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

2026-06-05T15:20:50+00:00

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

2026-04-02T12:42:19+00:00

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

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

2026-04-02T12:42:03+00:00

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

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

misc: fastrpc: Update dma_bits for CDSP support on Kaanapali SoC

2025-12-29T11:17:19+00:00

DSP currently supports 32-bit IOVA (32-bit PA + 4-bit SID) for both Q6 and user DMA (uDMA) access. This is being upgraded to 34-bit PA + 4-bit SID due to a hardware revision in CDSP for Kaanapali SoC, which expands the DMA addressable range. Update DMA bits configuration in the driver to support CDSP on Kaanapali SoC. Set the default `dma_bits` to 32-bit and update it to 34-bit based on CDSP and OF matching on the fastrpc node. Signed-off-by: Kumari Pallavi Reviewed-by: Dmitry Baryshkov Link: https://patch.msgid.link/20251226070534.602021-5-kumari.pallavi@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman