linux-next.git/drivers/usb/gadget/function/f_midi2.c, branch master

usb: gadget: f_midi2: fix use-after-free in string attribute show path

2026-09-01T14:41:17+00:00

f_midi2_opts_str_show() takes the string lock internally, but its callers dereference the opts->info. pointer before calling it, outside the lock. This races with f_midi2_opts_str_store(), which frees the old string under opts->lock when the attribute is written concurrently, the show path can read a pointer that gets freed before the lock inside str_show() is even taken. Change f_midi2_opts_str_show() to take a pointer to the string field, matching the existing pattern in f_midi2_opts_str_store(), and dereference it only after the lock is held. Update all three callers (iface_name, block name, and the EP string option macro) accordingly. Reported-by: syzbot+2280f1cca5e6b0c353e4@syzkaller.appspotmail.com Cc: stable Closes: https://syzkaller.appspot.com/bug?extid=2280f1cca5e6b0c353e4 Signed-off-by: Ivy Lopez Reviewed-by: Takashi Iwai Link: https://patch.msgid.link/20260816005434.34018-1-skunkolee@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: midi2: Fix null-pointer dereference in f_midi2_free_ep_reqs

2026-09-01T14:40:41+00:00

A null-pointer dereference occurs in f_midi2_free_ep_reqs() when attempting to clean up an endpoint that was never initialized. When configuring the MIDI 2.0 gadget via configfs and setting the block direction to SNDRV_UMP_DIR_INPUT, the initialization of the midi1_ep_out endpoint is explicitly skipped during the gadget bind phase (f_midi2_bind()). As a result, the usb_ep->card field remains NULL. Later, when the host sets the alternate setting, f_midi2_set_alt() unconditionally stops both the IN and OUT endpoints by calling f_midi2_stop_eps(), which in turn calls f_midi2_free_ep_reqs() for both endpoints. When f_midi2_free_ep_reqs() is called for the uninitialized midi1_ep_out, it attempts to dereference usb_ep->card to determine the number of requests to free, leading to a crash. Fix this by using usb_ep->num_reqs instead of usb_ep->card->info.num_reqs in f_midi2_free_ep_reqs(). usb_ep->num_reqs is correctly set during f_midi2_init_ep() and remains 0 if the endpoint was never initialized, safely avoiding the loop. For consistency, apply the same change to f_midi2_alloc_ep_reqs(). Oops: general protection fault, probably for non-canonical address 0xdffffc00000000ee: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000770-0x0000000000000777] ... RIP: 0010:f_midi2_free_ep_reqs drivers/usb/gadget/function/f_midi2.c:1166 [inline] RIP: 0010:f_midi2_stop_eps+0x28e/0x4d0 drivers/usb/gadget/function/f_midi2.c:1246 ... Call Trace: f_midi2_set_alt+0x11c/0xf00 drivers/usb/gadget/function/f_midi2.c:1296 composite_setup+0x1ffd/0x3480 drivers/usb/gadget/composite.c:1933 configfs_composite_setup+0xbd/0x100 drivers/usb/gadget/configfs.c:1877 Fixes: 8b645922b223 ("usb: gadget: Add support for USB MIDI 2.0 function driver") Cc: stable Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+bbb6dad313f4aaa8da6b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bbb6dad313f4aaa8da6b Link: https://syzkaller.appspot.com/ai_job?id=8ce30b1a-8cf7-4e38-bcf7-1f69e6f6313f Signed-off-by: Aleksandr Nogikh Reviewed-by: Takashi Iwai Closes: https://syzkaller.appspot.com/bug?extid=01a17afb30637396955e Link: https://patch.msgid.link/cafe65f4-e1bb-46a3-901d-732814b861b2@mail.kernel.org Signed-off-by: Greg Kroah-Hartman

usb: gadget: midi2: remove default configfs groups on teardown

2026-08-14T01:48:13+00:00

f_midi2_alloc_inst() creates default configfs child groups for the default endpoint and default block using configfs_add_default_group(), setting their internal refcount to 1. However, during function teardown in f_midi2_free_inst() or EP cleanup in f_midi2_ep_opts_release(), configfs_remove_default_groups() is never called, therefore never dropping the refcount and leaking struct f_midi2_ep_opts and f_midi2_block_opts. Add the missing configfs_remove_default_groups() in the afformentioned functions to free the structs properly. Fixes: 8b645922b223 ("usb: gadget: Add support for USB MIDI 2.0 function driver") Cc: stable@vger.kernel.org Reported-by: syzbot+eaa106d192c9daf37f95@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=eaa106d192c9daf37f95 Tested-by: syzbot+eaa106d192c9daf37f95@syzkaller.appspotmail.com Signed-off-by: Joshua Crofts Link: https://patch.msgid.link/20260730135811.1498-1-joshua.crofts1@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: functionfs: Use safer strscpy() instead of strcpy()

2026-03-11T14:39:04+00:00

Use a safer function strscpy() instead of strcpy() for copying to arrays. Only idiomatic code replacement, and no functional changes. Signed-off-by: Ai Chao Link: https://patch.msgid.link/20260310094434.3639602-4-aichao@kylinos.cn Signed-off-by: Greg Kroah-Hartman

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

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

usb: gadget: Constify struct configfs_item_operations and configfs_group_operations

2025-12-23T14:31:01+00:00

'struct configfs_item_operations' and 'configfs_group_operations' are not modified in these drivers. Constifying these structures moves some data to a read-only section, so increases overall security, especially when the structure holds some function pointers. On a x86_64, with allmodconfig, as an example: Before: ====== text data bss dec hex filename 65061 20968 256 86285 1510d drivers/usb/gadget/configfs.o After: ===== text data bss dec hex filename 66181 19848 256 86285 1510d drivers/usb/gadget/configfs.o Signed-off-by: Christophe JAILLET Link: https://patch.msgid.link/49cec1cb84425f854de80b6d69b53a5a3cda8189.1766164523.git.christophe.jaillet@wanadoo.fr Signed-off-by: Greg Kroah-Hartman

usb: gadget: midi2: Fix MIDI2 IN EP max packet size

2025-09-06T13:30:47+00:00

The EP-IN of MIDI2 (altset 1) wasn't initialized in f_midi2_create_usb_configs() as it's an INT EP unlike others BULK EPs. But this leaves rather the max packet size unchanged no matter which speed is used, resulting in the very slow access. And the wMaxPacketSize values set there look legit for INT EPs, so let's initialize the MIDI2 EP-IN there for achieving the equivalent speed as well. Fixes: 8b645922b223 ("usb: gadget: Add support for USB MIDI 2.0 function driver") Cc: stable Signed-off-by: Takashi Iwai Link: https://lore.kernel.org/r/20250905133240.20966-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman