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commit 9fea3a40f6b07de977a2783270c8c3bc82544d45 upstream.
This patch fixes a regression on setting up asynchronous commands to use
external trigger sources when board-specific routing information is
missing.
`ni_find_device_routes()` (called via `ni_assign_device_routes()`) finds
the table of register values for the device family and the set of valid
routes for the specific board. If both are found,
`tables->route_values` is set to point to the table of register values
for the device family and `tables->valid_routes` is set to point to the
list of valid routes for the specific board. If either is not found,
both `tables->route_values` and `tables->valid_routes` are left set at
their initial null values (initialized by `ni_assign_device_routes()`)
and the function returns `-ENODATA`.
Returning an error results in some routing functionality being disabled.
Unfortunately, leaving `table->route_values` set to `NULL` also breaks
the setting up of asynchronous commands that are configured to use
external trigger sources. Calls to `ni_check_trigger_arg()` or
`ni_check_trigger_arg_roffs()` while checking the asynchronous command
set-up would result in a null pointer dereference if
`table->route_values` is `NULL`. The null pointer dereference is fixed
in another patch, but it now results in failure to set up the
asynchronous command. That is a regression from the behavior prior to
commit 347e244884c3 ("staging: comedi: tio: implement global tio/ctr
routing") and commit 56d0b826d39f ("staging: comedi: ni_mio_common:
implement new routing for TRIG_EXT").
Change `ni_find_device_routes()` to set `tables->route_values` and/or
`tables->valid_routes` to valid information even if the other one can
only be set to `NULL` due to missing information. The function will
still return an error in that case. This should result in
`tables->valid_routes` being valid for all currently supported device
families even if the board-specific routing information is missing.
That should be enough to fix the regression on setting up asynchronous
commands to use external triggers for boards with missing routing
information.
Fixes: 347e244884c3 ("staging: comedi: tio: implement global tio/ctr routing")
Fixes: 56d0b826d39f ("staging: comedi: ni_mio_common: implement new routing for TRIG_EXT").
Cc: <stable@vger.kernel.org> # 4.20+
Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200114182532.132058-3-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 01e20b664f808a4f3048ca3f930911fd257209bd upstream.
In `ni_find_route_source()`, `tables->route_values` gets dereferenced.
However it is possible that `tables->route_values` is `NULL`, leading to
a null pointer dereference. `tables->route_values` will be `NULL` if
the call to `ni_assign_device_routes()` during board initialization
returned an error due to missing device family routing information or
missing board-specific routing information. For example, there is
currently no board-specific routing information provided for the
PCIe-6251 board and several other boards, so those are affected by this
bug.
The bug is triggered when `ni_find_route_source()` is called via
`ni_check_trigger_arg()` or `ni_check_trigger_arg_roffs()` when checking
the arguments for setting up asynchronous commands. Fix it by returning
`-EINVAL` if `tables->route_values` is `NULL`.
Even with this fix, setting up asynchronous commands to use external
trigger sources for boards with missing routing information will still
fail gracefully. Since `ni_find_route_source()` only depends on the
device family routing information, it would be better if that was made
available even if the board-specific routing information is missing.
That will be addressed by another patch.
Fixes: 4bb90c87abbe ("staging: comedi: add interface to ni routing table information")
Cc: <stable@vger.kernel.org> # 4.20+
Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200114182532.132058-2-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Adds interface and associated unittests for accessing/looking-up/validating
the new ni routing table information.
Signed-off-by: Spencer E. Olson <olsonse@umich.edu>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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