A malicious USB device with the TASCAM US-144MKII device id can have a
configuration containing bInterfaceNumber=1 but no interface 0.  USB
configuration descriptors are not required to assign interface numbers
sequentially, so usb_ifnum_to_if(dev, 0) returns will NULL, which will
then be dereferenced directly.

Fix this up by checking the return value properly.

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Fixes: dee1bcf28a3d ("ALSA: usb-audio: Add initial driver for TASCAM US-144MKII")
Cc: stable <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2026040955-fall-gaining-e338@gregkh
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Similarly, USB core holds a reference to all interfaces in the active
configuration so there is no need for a driver to take a reference to a
sibling interface only to release it at disconnect either.

Drop the redundant references to reduce cargo culting, make it easier to
spot drivers where extra references are needed, and reduce the risk of
memory leaks when drivers fail to release them.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260305111810.18688-1-johan@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

We don't process this driver code for kernel-doc, and the "/**" marker
leads to warnings with W=1 builds.  Drop the superfluous markers, and
also fix the invalid mark up, too.

Link: https://patch.msgid.link/20260226155456.1092186-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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 <torvalds@linux-foundation.org>

This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.

As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.

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

We used to have a variable declaration with __free() initialized with
NULL.  This was to keep the old coding style rule, but recently it's
relaxed and rather recommends to follow the new rule to declare in
place of use for __free() -- which avoids potential deadlocks or UAFs
with nested cleanups.

Although the current code has no bug, per se, let's follow the new
standard and move the declaration to the place of assignment (or
directly assign the allocated result) instead of NULL initializations.

Fixes: 67afec157fe6 ("ALSA: usb-audio: us144mkii: Add MIDI support and mixer controlsj")
Fixes: a2a2210f2c2e ("ALSA: usb-audio: us144mkii: Implement audio playback and feedback")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20251216140634.171890-11-tiwai@suse.de

Replace the manual mutex lock/unlock pairs with guard() for code
simplification.

Only code refactoring, and no behavior change.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250829150724.6886-4-tiwai@suse.de

Add a handshake value of 0x32, which is required when the device
was previously used by another OS with the official drivers.

Correct the last byte of the MIDI output protocol to 0xe0.

Also, remove the unused DRIVER_VERSION macro.

Signed-off-by: Šerif Rami <ramiserifpersia@gmail.com>
Link: https://patch.msgid.link/20250825072557.7670-1-ramiserifpersia@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>