---
- branch: MAIN
  date: Sun Mar  6 09:03:42 UTC 2022
  files:
  - new: '1.199'
    old: '1.198'
    path: src/sys/dev/usb/usb.c
    pathrev: src/sys/dev/usb/usb.c@1.199
    type: modified
  id: 20220306T090342Z.029417aab104fa3c17143fe555311f6fc464bed9
  log: |
    usb(4): Use atomics for usb_async_proc.

    This is written under proc_lock and read without it in usb_add_event,
    so using atomics pacifies the sanitizer.  No memory ordering needed
    because the value isn't actually used until the softint runs, using
    it under proc_lock.  Kind of a micro-optimization, but let's avoid
    contention on proc_lock in the common case of no usb_async_proc set
    up (why is this a system global, anyway? and why is there a softint
    if usb_add_event always runs at IPL_NONE?).

    Reported-by: syzbot+1b2fa68535e5b0f3dcaa@syzkaller.appspotmail.com
  module: src
  subject: 'CVS commit: src/sys/dev/usb'
  unixtime: '1646557422'
  user: riastradh