Pull rpmsg update from Bjorn Andersson:

 - Fix use-after-free in rpmsg-char driver

* tag 'rpmsg-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux:
  rpmsg: char: Fix use-after-free on probe error path

rpmsg_chrdev_probe() stores the newly allocated eptdev in the default
endpoint's priv pointer before calling rpmsg_chrdev_eptdev_add(). If
rpmsg_chrdev_eptdev_add() then fails, its error path frees eptdev while
the default endpoint may still dispatch callbacks with the stale priv
pointer.

Avoid publishing eptdev through the default endpoint until
rpmsg_chrdev_eptdev_add() succeeds. Messages received before the priv
pointer is published should be ignored by rpmsg_ept_cb(). Flow-control
updates can hit rpmsg_ept_flow_cb() in the same window, so make both
callbacks return success when priv is NULL.

Fixes: bc69d1066569 ("rpmsg: char: Introduce the "rpmsg-raw" channel")
Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20260601183247.1962010-1-dbgh9129@gmail.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.

Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.

Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]

Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1]
Reported-by: Gui-Dong Han <hanguidong02@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789
Fixes: e95060478244 ("rpmsg: Introduce a driver override mechanism")
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260505133935.3772495-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

The rpmsg_send(), rpmsg_sendto() and other variants of sending
interfaces should only send the passed data, without modifying its
contents, so mark pointer 'data' as pointer to const.  All users of this
interface already follow this approach, so only the function
declarations have to be updated.

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260317-rpmsg-send-const-v3-3-4d7fd27f037f@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

The class_destroy() function documents that:

  Note, the pointer to be destroyed must have been created with a call
  to class_create().

However, class_create() is deprecated. rpmsg already uses
class_register() but the class_destroy() calls should also be replaced
with class_unregister().

Link: https://lore.kernel.org/all/2023040244-duffel-pushpin-f738@gregkh/
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20260308140850.1138376-1-jkoolstra@xs4all.nl
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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 <kees@kernel.org>

The driver_override_show function reads the driver_override string
without holding the device_lock. However, the store function modifies
and frees the string while holding the device_lock. This creates a race
condition where the string can be freed by the store function while
being read by the show function, leading to a use-after-free.

To fix this, replace the rpmsg_string_attr macro with explicit show and
store functions. The new driver_override_store uses the standard
driver_set_override helper. Since the introduction of
driver_set_override, the comments in include/linux/rpmsg.h have stated
that this helper must be used to set or clear driver_override, but the
implementation was not updated until now.

Because driver_set_override modifies and frees the string while holding
the device_lock, the new driver_override_show now correctly holds the
device_lock during the read operation to prevent the race.

Additionally, since rpmsg_string_attr has only ever been used for
driver_override, removing the macro simplifies the code.

Fixes: 39e47767ec9b ("rpmsg: Add driver_override device attribute for rpmsg_device")
Cc: stable@vger.kernel.org
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://lore.kernel.org/r/20251202174948.12693-1-hanguidong02@gmail.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Previously, polling an rpmsg endpoint (e.g. /dev/ttyRPMSGx) would
generate EPOLLIN events but no EPOLLOUT events.

Unfortunately, poll support means that we can no longer disable
tx-complete interrupts as there is no way to know whether a poller is
waiting in sendq, so we always need notifications.

Signed-off-by: Patrick Oppenlander <patrick.oppenlander@gmail.com>
Link: https://lore.kernel.org/r/20251022032817.320378-1-patrick.oppenlander@gmail.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

rpmsg device remove code is duplicated in at-least 2-3 places, add a
helper function to remove this duplicated code.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250822100043.2604794-3-srinivas.kandagatla@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>