Re: [syzbot] [usb?] KMSAN: kernel-usb-infoleak in usbtmc_write

[syzbot <syzbot+9d34f80f841e948c3fdb@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: kernel-usb-infoleak in usbtmc_write

=====================================================
BUG: KMSAN: kernel-usb-infoleak in usb_submit_urb+0x597/0x2350 drivers/usb/core/urb.c:430
 usb_submit_urb+0x597/0x2350 drivers/usb/core/urb.c:430
 usbtmc_write+0xc4f/0x1240 drivers/usb/class/usbtmc.c:1607
 vfs_write+0x493/0x1550 fs/read_write.c:588
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3998 [inline]
 slab_alloc_node mm/slub.c:4041 [inline]
 __kmalloc_cache_noprof+0x4f0/0xb00 mm/slub.c:4188
 kmalloc_noprof include/linux/slab.h:681 [inline]
 usbtmc_create_urb drivers/usb/class/usbtmc.c:757 [inline]
 usbtmc_write+0x3d3/0x1240 drivers/usb/class/usbtmc.c:1547
 vfs_write+0x493/0x1550 fs/read_write.c:588
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Byte 15 of 16 is uninitialized
Memory access of size 16 starts at ffff88810a6a0000

CPU: 0 UID: 0 PID: 6214 Comm: syz.3.81 Not tainted 6.11.0-rc6-syzkaller-00070-gc763c4339688-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
=====================================================


Tested on:

commit:         c763c433 Merge tag 'bcachefs-2024-09-04' of git://evil..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13324667980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=35c699864e165c51
dashboard link: https://syzkaller.appspot.com/bug?extid=9d34f80f841e948c3fdb
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15a7fd29980000