[src/jmcneill-usbmp]: src/sys/dev/usb - noticed a concurrency issue with bus-...

[mrg <mrg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9bca0966cd2e
branches:  jmcneill-usbmp
changeset: 771815:9bca0966cd2e
user:      mrg <mrg%NetBSD.org@localhost>
date:      Sat Feb 25 12:57:32 2012 +0000

description:
- noticed a concurrency issue with bus->intr_context member.  sometimes
  the host controller interrupt lock is held, sometimes the USB thread
  lock is held, and i've seen at least two cases where the non-hard or
  non-soft interrupt handler triggered this test in a code path that
  could not have raised it itself.  note that this needs attention.
- update some lists.

diffstat:

 sys/dev/usb/TODO.usbmp |  34 +++++++++++++++++++++++++++++++++-
 1 files changed, 33 insertions(+), 1 deletions(-)

diffs (51 lines):

diff -r e98a2b3f810f -r 9bca0966cd2e sys/dev/usb/TODO.usbmp
--- a/sys/dev/usb/TODO.usbmp    Sat Feb 25 12:53:34 2012 +0000
+++ b/sys/dev/usb/TODO.usbmp    Sat Feb 25 12:57:32 2012 +0000
@@ -1,4 +1,4 @@
-$NetBSD: TODO.usbmp,v 1.1.2.2 2012/02/25 10:26:23 mrg Exp $
+$NetBSD: TODO.usbmp,v 1.1.2.3 2012/02/25 12:57:32 mrg Exp $
 
 
 the majority of the USB MP device interface is documented in usbdivar.h.
@@ -17,9 +17,41 @@
 add lots of asserts
 
 
+bus->intr_context issues:
+  - intr_context is raised when the USB lock is dropped to call the call back
+    for usb_transfer_complete(), then some other cpu can run, take the lock
+    and end up triggering an "intr_context != 0" condition.
+  - usb_transfer_complete() is sometimes called with host intr lock held,
+    sometimes with usb lock
+  - hardware interrupt takes host intr lock to protect intr_context, but
+    software interrupt takes USB lock.
+  - need to re-consider soft_intr() API
+
+
 wakeup removal core:
   - usb_detach_wait/wakeup() -> add a usb_detach_cvwait/broadcast() that
     take a mutex
+  - drivers:
+      if_aue.c
+      if_axe.c
+      if_udav.c
+      if_url.c
+      ubt.c
+      ucom.c
+      ucycom.c
+      ugen.c
+      uhid.c           - done, untested
+      uhso.c
+      uirda.c
+      ulpt.c
+      umass.c          - done, untested
+      urio.c
+      usbdi_util.c
+      usbdi_util.h
+      uscanner.c
+      usscanner.c
+      ustir.c
+      utoppy.c
 
 
 convert uhidev users to MPSAFE: