CVS commit: src/sys/kern

[Juergen Hannken-Illjes <hannken%netbsd.org@localhost>]

Module Name:    src
Committed By:   hannken
Date:           Wed Sep 24 08:19:19 UTC 2008

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

Log Message:
Resolve a race when physio_done signals completion before it tries to
free a buffer.  This will fail if the buffer owner has a chance to
modify the BC_DONTFREE flag before putphysbuf() examines it.

Fix by removing get/putphysbuf() and BC_DONTFREE.  Physio_done() now
has an explicit test for a buffer coming from the call of physio().

Observed by Lars Nordlund when writing a DVD with growisofs, see PR kern/39536.

Reviewed by: Jason Thorpe <thorpej%netbsd.org@localhost>


To generate a diff of this commit:
cvs rdiff -r1.87 -r1.88 src/sys/kern/kern_physio.c

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