CVS commit: src/sys/kern

["Kengo NAKAHARA" <knakahara%netbsd.org@localhost>]

Module Name:    src
Committed By:   knakahara
Date:           Thu Dec 24 02:27:14 UTC 2015

Modified Files:
        src/sys/kern: kern_softint.c

Log Message:
fix the following softint parallel operation problem.

(0) softint handler "handler A" is established
(1) CPU#X does softint_schedule() for "handler A"
    - the softhand_t is set SOFTINT_PENDING flag
    - the softhand_t is NOT set SOFTINT_ACTIVE flag yet
(2) CPU#X begins other H/W interrupt processing
(3) CPU#Y does softint_disestablish() for "handler A"
    - waits until softhand_t's SOFTINT_ACTIVE of all CPUs is clear
    - the softhand_t is set not SOFTINT_ACTIVE but SOFTINT_PENDING,
      so CPU#Y does not wait
    - unset the function of "handler A"
(4) CPU#X does softint_execute()
    - the function of "handler A" is already clear, so panic


To generate a diff of this commit:
cvs rdiff -u -r1.41 -r1.42 src/sys/kern/kern_softint.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.