Chunwei Chen a3c1eb7772 mutex: force serialization on mutex_exit() to fix races ... It is known that mutexes in Linux are not safe when using them to synchronize the freeing of object in which the mutex is embedded: http://lwn.net/Articles/575477/ The known places in ZFS which are suspected to suffer from the race condition are zio->io_lock and dbuf->db_mtx. * zio uses zio->io_lock and zio->io_cv to synchronize freeing between zio_wait() and zio_done(). * dbuf uses dbuf->db_mtx to protect reference counting. This patch fixes this kind of race by forcing serialization on mutex_exit() with a spin lock, making the mutex safe by sacrificing a bit of performance and memory overhead. This issue most commonly manifests itself as a deadlock in the zio pipeline caused by a process spinning on the damaged mutex. Similar deadlocks have been reported for the dbuf->db_mtx mutex. And it can also cause a NULL dereference or bad paging request under the right circumstances. This issue any many like it are linked off the zfsonlinux/zfs#2523 issue. Specifically this fix resolves at least the following outstanding issues: zfsonlinux/zfs#401 zfsonlinux/zfs#2523 zfsonlinux/zfs#2679 zfsonlinux/zfs#2684 zfsonlinux/zfs#2704 zfsonlinux/zfs#2708 zfsonlinux/zfs#2517 zfsonlinux/zfs#2827 zfsonlinux/zfs#2850 zfsonlinux/zfs#2891 zfsonlinux/zfs#2897 zfsonlinux/zfs#2247 zfsonlinux/zfs#2939 Signed-off-by: Chunwei Chen <tuxoko@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Richard Yao <ryao@gentoo.org> Closes #421		2014-12-19 10:18:47 -08:00
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fm	Kernel header installation should respect --prefix	2014-10-28 09:31:48 -07:00
fs	Kernel header installation should respect --prefix	2014-10-28 09:31:48 -07:00
sysevent	Kernel header installation should respect --prefix	2014-10-28 09:31:48 -07:00
acl_impl.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
acl.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
atomic.h	Remove atomic64_xchg() wrappers	2014-10-17 15:11:50 -07:00
attr.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
bitmap.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
bootconf.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
bootprops.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
buf.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
byteorder.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
callb.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
callo.h	Emulate illumos interface cv_timedwait_hires()	2013-11-04 09:49:24 -08:00
cmn_err.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
compress.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
condvar.h	Emulate illumos interface cv_timedwait_hires()	2013-11-04 09:49:24 -08:00
conf.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
console.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
cpupart.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
cpuvar.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
crc32.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
cred.h	Remove credential configure checks.	2014-10-17 15:11:51 -07:00
ctype.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
ddi.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
debug.h	Retire legacy debugging infrastructure	2014-11-19 10:35:07 -08:00
dirent.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
disp.h	Add kpreempt() compatibility macro	2013-10-09 13:52:55 -07:00
dkio.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
dklabel.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
dnlc.h	Remove shrink_{i,d}node_cache() wrappers	2014-10-17 15:11:51 -07:00
dumphdr.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
efi_partition.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
errno.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
extdirent.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
fcntl.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
file.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
idmap.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
int_limits.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
int_types.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
inttypes.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
isa_defs.h	Add support for aarch64 (ARMv8)	2014-04-25 15:25:32 -07:00
kidmap.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
kmem.h	Retire legacy debugging infrastructure	2014-11-19 10:35:07 -08:00
kobj.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
kstat.h	3537 add kstat_waitq_enter and friends	2013-10-25 13:41:52 -07:00
list.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
Makefile.am	Kernel header installation should respect --prefix	2014-10-28 09:31:48 -07:00
mkdev.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
mntent.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
modctl.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
mode.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
mount.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
mutex.h	mutex: force serialization on mutex_exit() to fix races	2014-12-19 10:18:47 -08:00
note.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
open.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
param.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
pathname.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
policy.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
pool.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
priv_impl.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
proc.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
processor.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
pset.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
random.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
refstr.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
resource.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
rwlock.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
sdt.h	Define SET_ERROR()	2013-10-09 14:20:46 -07:00
sid.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
signal.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
stat.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
stropts.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
sunddi.h	Update code to use misc_register()/misc_deregister()	2014-10-17 15:07:28 -07:00
sunldi.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
sysdc.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
sysevent.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
sysmacros.h	Map highbit64() to fls64()	2014-10-17 15:11:50 -07:00
systeminfo.h	Simplify hostid logic	2014-04-14 09:04:41 -07:00
systm.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
t_lock.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
taskq.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
thread.h	De-inline spl_kthread_create().	2014-04-09 19:17:12 -07:00
time.h	Simplify the time compatibility wrappers	2014-10-17 15:11:50 -07:00
timer.h	Add ddi_time_after and friends	2014-04-14 09:32:01 -07:00
tsd.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
types32.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
types.h	Remove compat includes from sys/types.h	2014-11-19 10:35:12 -08:00
u8_textprep.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
uio.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
unistd.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
va_list.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
varargs.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
vfs_opreg.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
vfs.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
vmsystm.h	Remove global memory variables	2014-10-17 15:11:51 -07:00
vnode.h	Cleanup vn_rename() and vn_remove()	2014-08-13 16:25:44 -07:00
zmod.h	Refresh links to web site	2013-03-04 19:09:34 -08:00
zone.h	Refresh links to web site	2013-03-04 19:09:34 -08:00