linux-stable.git/drivers/misc, branch linux-5.15.y

misc: fastrpc: Remove buffer from list prior to unmap operation

2026-08-27T12:28:19+00:00

[ Upstream commit 6102ceb4eab845743ee57acd3863fbd06e93c927 ]

fastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is
getting removed from the list after it is unmapped from DSP. This can
create potential race conditions if multiple threads invoke unmap
concurrently, where one thread may remove the entry from the list while
another thread's unmap operation is still ongoing.

Fix this by removing the buffer entry from the list before calling the
unmap operation. If the unmap fails, the entry is re-added to the list
so that userspace can retry the unmap, or alternatively, the buffer
will be cleaned up during device release when the DSP process is torn
down and all DSP-side mappings are freed along with remaining buffers
in the list.

Fixes: 2419e55e532de ("misc: fastrpc: add mmap/unmap support")
Cc: stable@kernel.org
Reviewed-by: Dmitry Baryshkov 
Signed-off-by: Ekansh Gupta 
Signed-off-by: Jianping Li 
Signed-off-by: Srinivas Kandagatla 
Link: https://patch.msgid.link/20260724223342.629168-3-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Rework fastrpc_req_munmap

2026-08-27T12:28:19+00:00

[ Upstream commit 72fa6f7820c4cf96c5f7aabc4e54bdf52d1e2ac2 ]

Move the lookup of the munmap request to the fastrpc_req_munmap and pass
on only the buf to the lower level fastrpc_req_munmap_impl. That way
we can use the lower level fastrpc_req_munmap_impl on error path in
fastrpc_req_mmap to free the buf without searching for the munmap
request it belongs to.

Co-developed-by: Srinivas Kandagatla 
Signed-off-by: Abel Vesa 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20221125071405.148786-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 6102ceb4eab8 ("misc: fastrpc: Remove buffer from list prior to unmap operation")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: separate fastrpc device from channel context

2026-08-27T12:28:19+00:00

[ Upstream commit 965602eabb57d086466ad749e81941e3dd66b595 ]

Currently fastrpc misc device instance is within channel context struct
with a kref. So we have 2 structs with refcount, both of them managing the
same channel context structure.

Separate fastrpc device from channel context and by adding a dedicated
fastrpc_device structure, this should clean the structures a bit and also help
when adding secure device node support.

Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20220214161002.6831-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 6102ceb4eab8 ("misc: fastrpc: Remove buffer from list prior to unmap operation")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: fix memory leak in fastrpc_channel_ctx_free

2026-08-19T15:14:16+00:00

commit 2fae94ee14f7fea11d3f95e10383a87c01d21518 upstream.

The 'ctx_idr' is initialized but never destroyed when
the channel context is freed, leading to a memory leak.
Add idr_destroy() to properly clean up the IDR resources.

Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model")
Cc: stable@vger.kernel.org
Signed-off-by: Eddie Lin 
Reviewed-by: Ekansh Gupta 
Signed-off-by: Srinivas Kandagatla 
Link: https://patch.msgid.link/20260724223342.629168-6-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: fix channel ctx ref leak when session alloc fails

2026-08-19T15:14:16+00:00

commit 310f7868399668c6d99d88acc9c4cf3462e69d5b upstream.

fastrpc_channel_ctx_get() is called in fastrpc_device_open() before
fastrpc_session_alloc(). If session alloc fails, the error path
returns -EBUSY without calling fastrpc_channel_ctx_put(), leaking
the reference. Fix by adding the missing put.

Fixes: 278d56f970ae ("misc: fastrpc: Reference count channel context")
Cc: stable@kernel.org
Signed-off-by: Anandu Krishnan E 
Reviewed-by: Dmitry Baryshkov 
Signed-off-by: Srinivas Kandagatla 
Link: https://patch.msgid.link/20260724223342.629168-5-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Fix NULL pointer dereference in rpmsg callback

2026-07-04T11:39:40+00:00

[ Upstream commit 5401fb4fe10fac6134c308495df18ed74aebb9c4 ]

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: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

misc: fastrpc: Add dma_mask to fastrpc_channel_ctx

2026-07-04T11:39:40+00:00

[ Upstream commit 9bde43a0e2f469961e18d0a3496a9a74379c22bf ]

dma_set_mask_and_coherent only updates the mask to which the device
dma_mask pointer points to. Add a dma_mask to the channel ctx and set
the device dma_mask to point to that, otherwise the dma_set_mask will
return an error and the dma_set_coherent_mask will be skipped too.

Co-developed-by: Srinivas Kandagatla 
Signed-off-by: Abel Vesa 
Signed-off-by: Srinivas Kandagatla 
Link: https://lore.kernel.org/r/20221125071405.148786-11-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 5401fb4fe10f ("misc: fastrpc: Fix NULL pointer dereference in rpmsg callback")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

use less confusing names for iov_iter direction initializers

2026-06-19T11:33:46+00:00

[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ]

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro 
Stable-dep-of: a4f0b001782b ("vsock/virtio: reset connection on receiving queue overflow")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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