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20e4afbfbb
freebsd-nq/sys
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Konstantin Belousov 20e4afbfbb On munlock(), unwire correct page. 
It is possible, for complex fork()/collapse situations, to have
sibling address spaces to partially share shadow chains. If one
sibling performs wiring, it can happen that a transient page, invalid
and busy, is installed into a shadow object which is visible to other
sibling for the duration of vm_fault_hold().  When the backing object
contains the valid page, and the wiring is performed on read-only
entry, the transient page is eventually removed.

But the sibling which observed the transient page might perform the
unwire, executing vm_object_unwire().  There, the first page found in
the shadow chain is considered as the page that was wired for the
mapping.  It is really the page below it which is wired.  So we unwire
the wrong page, either triggering the asserts of breaking the page'
wire counter.

As the fix, wait for the busy state to finish if we find such page
during unwire, and restart the shadow chain walk after the sleep.

Reported and tested by:	pho
Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D14184
2018-02-05 12:49:20 +00:00
..
amd64 When switching IBRS on, also enable STIBP (Single Thread Indirect 2018-01-31 16:56:02 +00:00
arm Implement mitigation for Spectre version 2 attacks on ARMv7. 2018-01-27 11:19:41 +00:00
arm64 Only promote userspace mappings to superpages. This was dropped in r328510, 2018-02-01 14:26:26 +00:00
bsm sys: further adoption of SPDX licensing ID tags. 2017-11-20 19:43:44 +00:00
cam Do the book-keeping on release before we release the reference. The 2018-01-29 18:07:14 +00:00
cddl ZFS ARC: restore illumos uses of 'needfree' that were removed in r325851 2018-02-02 12:57:33 +00:00
compat Add kern.ipc.{msqids,semsegs,sema} sysctls for FreeBSD32. 2018-02-02 18:03:12 +00:00
conf After r328426, g_label depends on UFS (option FFS) code to read UFS 2018-02-03 09:15:13 +00:00
contrib MFV r328490: Update libfdt to github:f1879e1 2018-01-27 21:25:45 +00:00
crypto ccp(4): Store IV in output buffer in GCM software fallback when requested 2018-01-27 07:41:31 +00:00
ddb Implement 'domainset', a cpuset based NUMA policy mechanism. This allows 2018-01-12 22:48:23 +00:00
dev [arswitch] Enable ATU dump support for the AR9340. 2018-02-05 07:05:28 +00:00
dts Add a skeleton Clock Manager for RPi2/3, and use that from pwm 2018-01-22 07:10:30 +00:00
fs Fix mistake in case of zeroed inode check. 2018-01-29 22:15:46 +00:00
gdb sys/gdb: further adoption of SPDX licensing ID tags. 2017-11-27 15:16:59 +00:00
geom geom: don't write stack garbage in disk labels 2018-02-04 14:49:55 +00:00
gnu Revert r327828, r327949, r327953, r328016-r328026, r328041: 2018-01-21 15:42:36 +00:00
i386 IBRS support, AKA Spectre hardware mitigation. 2018-01-31 14:36:27 +00:00
isa Add ISA PNP tables to ISA drivers. Fix a few incidental comments. 2018-01-29 00:22:30 +00:00
kern Add kern.ipc.{msqids,semsegs,sema} sysctls for FreeBSD32. 2018-02-02 18:03:12 +00:00
kgssapi sys/kgssapi: general adoption of SPDX licensing ID tags. 2017-11-27 15:49:00 +00:00
libkern SPDX: fix wrong license ID tag in libkern. 2017-12-28 01:20:30 +00:00
mips [ar71xx] Fix DB120 AHB device hints in the new world order. 2018-02-05 04:48:41 +00:00
modules Correct MD patch in linux64 module Makefile 2018-01-29 01:59:04 +00:00
net BPF: Switch to 32 bit compatible mode only when thread is 32 bit 2018-01-25 12:13:41 +00:00
net80211 net80211: sanitize input for ieee80211_output() 2017-12-30 00:40:34 +00:00
netgraph Revert r327828, r327949, r327953, r328016-r328026, r328041: 2018-01-21 15:42:36 +00:00
netinet Export tcp_always_keepalive for use by the Chelsio TOM module. 2018-01-30 23:01:37 +00:00
netinet6 Modify ip6_get_prevhdr() to be able use it safely. 2018-02-05 09:22:07 +00:00
netipsec Adopt revision 1.76 and 1.77 from NetBSD: 2018-01-24 19:48:25 +00:00
netpfil pf: Avoid warning without INVARIANTS 2018-02-01 07:52:06 +00:00
netsmb Unsign some values related to allocation. 2018-01-22 02:08:10 +00:00
nfs Do pass removing some write-only variables from the kernel. 2017-12-25 04:48:39 +00:00
nfsclient style: Remove remaining deprecated MALLOC/FREE macros 2018-01-25 22:25:13 +00:00
nfsserver sys: general adoption of SPDX licensing ID tags. 2017-11-27 15:23:17 +00:00
nlm Do pass removing some write-only variables from the kernel. 2017-12-25 04:48:39 +00:00
ofed sys: general adoption of SPDX licensing ID tags. 2017-11-27 15:23:17 +00:00
opencrypto Move per-operation data out of the csession structure. 2018-01-26 23:21:50 +00:00
powerpc Only look for L2 cache controllers for mpc85xx_cache 2018-02-04 20:07:08 +00:00
riscv Remove SFBUF_OPTIONAL_DIRECT_MAP and such hacks, replacing them across the 2018-01-19 17:46:31 +00:00
rpc Do pass removing some write-only variables from the kernel. 2017-12-25 04:48:39 +00:00
security Do pass removing some write-only variables from the kernel. 2017-12-25 04:48:39 +00:00
sparc64 Add ISA PNP tables to ISA drivers. Fix a few incidental comments. 2018-01-29 00:22:30 +00:00
sys psm(4): Add support for HP EliteBook 1040 ForcePads. 2018-01-31 21:14:59 +00:00
teken sys: general adoption of SPDX licensing ID tags. 2017-11-27 15:23:17 +00:00
tests
tools Avoid using \$. It's an unknown escape sequence. Some awks warn about 2018-01-28 05:13:08 +00:00
ufs When reading a cylinder group, break out reporting of check hash errors 2018-01-31 23:13:37 +00:00
vm On munlock(), unwire correct page. 2018-02-05 12:49:20 +00:00
x86 Expand IBRS TLA in sysctl help lines. 2018-01-31 16:54:05 +00:00
xdr sys: general adoption of SPDX licensing ID tags. 2017-11-27 15:23:17 +00:00
xen sys: general adoption of SPDX licensing ID tags. 2017-11-27 15:23:17 +00:00
Makefile Move sys/boot to stand. Fix all references to new location 2017-11-14 23:02:19 +00:00