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Ryan Stone 86a6fcd4ff Fix a false positive in a buf_ring assert
buf_ring contains an assert that checks whether an item being
enqueued already exists on the ring.  There is a subtle bug in
this assert.  An item can be returned by a peek() function and
freed, and then the consumer thread can be preempted before
calling advance().  If this happens the item appears to still be
on the queue, but another thread may allocate the item from the
free pool and wind up trying to enqueue it again, causing the
assert to trigger incorrectly.

Fix this by skipping the head of the consumer's portion of the
ring, as this index is what will be returned by peek().

Sponsored by:	Dell EMC Isilon
MFC After:	1 week
Differential Revision:	https://reviews.freebsd.org/D8685
Reviewed by:	hselasky
2016-12-01 21:08:42 +00:00
bin style(9). 2016-11-28 07:21:09 +00:00
cddl MFV r308989: 6428 set canmount=off on unmounted filesystem tries to 2016-11-24 10:11:09 +00:00
contrib MFC r309362: 2016-12-01 15:46:26 +00:00
crypto MFV r308196: 2016-11-02 06:49:25 +00:00
etc Finish incomplete comments in prior revision. I was going to fix this 2016-12-01 05:16:27 +00:00
gnu Add WITH_LLD_AS_LD build knob 2016-11-25 13:15:28 +00:00
include Use the correct name for the GCC macro indicating max_align_t is defined. 2016-11-29 00:16:19 +00:00
kerberos5 DIRDEPS_BUILD: Update dependencies 2016-06-14 16:55:05 +00:00
lib libstand: dosfs cstyle cleanup for return keyword. 2016-12-01 19:19:20 +00:00
libexec Fix _mips_rtld_bind() to handle ELF filters. 2016-11-23 20:21:53 +00:00
release Revert r309314, which breaks installing ports. 2016-11-30 22:00:25 +00:00
rescue DIRDEPS_BUILD: Update dependencies. 2016-11-13 00:11:30 +00:00
sbin Simplify test. 2016-12-01 04:35:38 +00:00
secure Prefer ACFLAGS over CFLAGS for compiling aarch64 assembly files. 2016-10-26 20:12:30 +00:00
share Revert r309314, which breaks installing ports. 2016-11-30 22:00:25 +00:00
sys Fix a false positive in a buf_ring assert 2016-12-01 21:08:42 +00:00
targets Merge ^/head r308491 through r308841. 2016-11-19 16:05:55 +00:00
tests Add test case for >65535 segment coredumps 2016-11-01 19:18:16 +00:00
tools Trying to autodetect legacy setups lead to problems when people 2016-11-28 21:29:01 +00:00
usr.bin locale: enable more warnings; fix them 2016-12-01 17:36:31 +00:00
usr.sbin Speling fixes and fix line endings for err_msg output. 2016-12-01 09:14:58 +00:00
.arcconfig callsign isn't required anymore 2016-09-29 06:19:45 +00:00
.arclint phabricator related changes: 2015-04-20 20:33:22 +00:00
COPYRIGHT Bump copyright year. 2015-12-31 11:21:45 +00:00
LOCKS
MAINTAINERS Remove myself from kern_timeout.c yeah! 2016-07-27 20:37:32 +00:00
Makefile Add full softfloat and hardfloat support for RISC-V. 2016-11-16 15:21:32 +00:00
Makefile.inc1 Revert r309314, which breaks installing ports. 2016-11-30 22:00:25 +00:00
Makefile.libcompat Fix in-tree GCC builds after r304681. 2016-08-23 19:29:37 +00:00
ObsoleteFiles.inc The function vm_page_cache() no longer exists. Remove its man page. 2016-11-27 01:44:31 +00:00
README Import subversion-1.9.5. 2016-12-01 07:45:05 +00:00
UPDATING Add UPDATING entry for clang/llvm 3.9.0 import. 2016-11-24 22:18:55 +00:00

This is the top level of the FreeBSD source directory.  This file
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The Makefile in this directory supports a number of targets for
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Building a kernel is a somewhat more involved process.  See build(7), config(8),
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etc		Template files for /etc.

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