[syzbot] [usb?] memory leak in try_get_usb_function_instance

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3dab139d4795 Merge tag 'rust-fixes-7.2-2' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=163a388e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=eaa106d192c9daf37f95
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111c11b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b5909e580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c49d395f8d0/disk-3dab139d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/deff2ace5e6a/vmlinux-3dab139d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c90a783f940/bzImage-3dab139d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eaa106...@syzkaller.appspotmail.com

2026/07/26 12:12:48 executed programs: 5
BUG: memory leak
unreferenced object 0xffff888112a69c00 (size 512):
comm "syz.0.19", pid 5954, jiffies 4294946869
hex dump (first 32 bytes):
08 9c a6 12 81 88 ff ff 65 70 2e 30 00 00 00 00 ........ep.0....
00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 ................
backtrace (crc 56e62c00):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4597 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
__kmalloc_cache_noprof+0x356/0x440 mm/slub.c:5485
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
f_midi2_ep_opts_create drivers/usb/gadget/function/f_midi2.c:2504 [inline]
f_midi2_alloc_inst+0xa0/0x250 drivers/usb/gadget/function/f_midi2.c:2666
try_get_usb_function_instance+0xb8/0x100 drivers/usb/gadget/functions.c:28
usb_get_function_instance+0x16/0x70 drivers/usb/gadget/functions.c:44
function_make+0xf5/0x240 drivers/usb/gadget/configfs.c:626
configfs_mkdir+0x2e9/0x6f0 fs/configfs/dir.c:1360
vfs_mkdir+0x16c/0x3a0 fs/namei.c:5276
filename_mkdirat+0x27c/0x300 fs/namei.c:5309
__do_sys_mkdirat fs/namei.c:5330 [inline]
__se_sys_mkdirat fs/namei.c:5327 [inline]
__x64_sys_mkdirat+0x39/0x60 fs/namei.c:5327
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff8881105a3f00 (size 256):
comm "syz.0.19", pid 5954, jiffies 4294946869
hex dump (first 32 bytes):
08 3f 5a 10 81 88 ff ff 62 6c 6f 63 6b 2e 30 00 .?Z.....block.0.
00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 ................
backtrace (crc f7f284e3):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4597 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
__kmalloc_cache_noprof+0x356/0x440 mm/slub.c:5485
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
f_midi2_block_opts_create+0x82/0x120 drivers/usb/gadget/function/f_midi2.c:2342
f_midi2_alloc_inst+0xe9/0x250 drivers/usb/gadget/function/f_midi2.c:2673
try_get_usb_function_instance+0xb8/0x100 drivers/usb/gadget/functions.c:28
usb_get_function_instance+0x16/0x70 drivers/usb/gadget/functions.c:44
function_make+0xf5/0x240 drivers/usb/gadget/configfs.c:626
configfs_mkdir+0x2e9/0x6f0 fs/configfs/dir.c:1360
vfs_mkdir+0x16c/0x3a0 fs/namei.c:5276
filename_mkdirat+0x27c/0x300 fs/namei.c:5309
__do_sys_mkdirat fs/namei.c:5330 [inline]
__se_sys_mkdirat fs/namei.c:5327 [inline]
__x64_sys_mkdirat+0x39/0x60 fs/namei.c:5327
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF


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Subject:
Author: joshua....@gmail.com

#syz test

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

drivers/usb/gadget/function/f_midi2.c:2643:57: error: 'struct usb_function_instance' has no member named 'groups'; did you mean 'group'?


Tested on:

commit: 11028ab6 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=eaa106d192c9daf37f95
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

patch: https://syzkaller.appspot.com/x/patch.diff?x=17dc25b9580000

[syzbot]

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+eaa106...@syzkaller.appspotmail.com
Tested-by: syzbot+eaa106...@syzkaller.appspotmail.com

Tested on:

commit: 11028ab6 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=16ad4aea580000

kernel config: https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=eaa106d192c9daf37f95
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

patch: https://syzkaller.appspot.com/x/patch.diff?x=137c25b9580000

Note: testing is done by a robot and is best-effort only.