MTRR rendezvous sequence using stop_one_cpu_nowait() can potentially
happen in parallel with another system wide rendezvous using
stop_machine(). This can lead to deadlock (The order in which
works are queued can be different on different cpu's. Some cpu's
will be running the first rendezvous handler and others will be running
the second rendezvous handler. Each set waiting for the other set to join
for the system wide rendezvous, leading to a deadlock).
MTRR rendezvous sequence is not implemented using stop_machine() as this
gets called both from the process context aswell as the cpu online paths
(where the cpu has not come online and the interrupts are disabled etc).
stop_machine() works with only online cpus.
For now, take the stop_machine mutex in the MTRR rendezvous sequence that
gets called from an online cpu (here we are in the process context
and can potentially sleep while taking the mutex). And the MTRR rendezvous
that gets triggered during cpu online doesn't need to take this stop_machine
lock (as the stop_machine() already ensures that there is no cpu hotplug
going on in parallel by doing get_online_cpus())
TBD: Pursue a cleaner solution of extending the stop_machine()
infrastructure to handle the case where the calling cpu is
still not online and use this for MTRR rendezvous sequence.
fixes: https://bugzilla.novell.com/show_bug.cgi?id=672008
Reported-by: Vadim Kotelnikov <vadimuzzz@inbox.ru>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/20110623182056.807230326@sbsiddha-MOBL3.sc.intel.com
Cc: stable@kernel.org # 2.6.35+, backport a week or two after this gets more testing in mainline
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: prevent bogus assert when trying to remove non-existent attribute
xfs: clear XFS_IDIRTY_RELEASE on truncate down
xfs: reset inode per-lifetime state when recycling it
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
HID: hid-multitouch: add support for a new Lumio dual-touch panel
HID: hid-multitouch: correct VID for Stantum panels
HID: hid-multitouch: ensure slots are initialized
* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
[S390] allow setting of upper 32 bit in smp_ctl_set_bit
[S390] hwsampler: Set a sane default sampling rate
[S390] s390: enforce HW limits for the initial sampling rate
[S390] kvm-s390: fix kconfig dependencies
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
cifs: propagate errors from cifs_get_root() to mount(2)
cifs: tidy cifs_do_mount() up a bit
cifs: more breakage on mount failures
cifs: close sget() races
cifs: pull freeing mountdata/dropping nls/freeing cifs_sb into cifs_umount()
cifs: move cifs_umount() call into ->kill_sb()
cifs: pull cifs_mount() call up
sanitize cifs_umount() prototype
cifs: initialize ->tlink_tree in cifs_setup_cifs_sb()
cifs: allocate mountdata earlier
cifs: leak on mount if we share superblock
cifs: don't pass superblock to cifs_mount()
cifs: don't leak nls on mount failure
cifs: double free on mount failure
take bdi setup/destruction into cifs_mount/cifs_umount
Acked-by: Steve French <smfrench@gmail.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: Remove unneeded version.h includes from sound/
ASoC: pxa-ssp: Correct check for stream presence
ASoC: imx: add missing module informations
ASoC: imx: Remove unused Kconfig SND_MXC_SOC_SSI entry
ALSA: HDA: Pinfix quirk for HP Z200 Workstation
ALSA: VIA HDA: Create a master amplifier control for VT1718S.
ALSA: VIA HDA: Mute/unmute mixer conncted to Headphone for VT1718S.
ALSA: VIA HDA: Modify initial verbs list for VT1718S.
ALSA: hda - Remove ALC268 model override for CPR2000
ALSA: HDA: Remove quirk for an HP device
ASoC: Remove unused and about to be broken SND_SOC_CUSTOM I/O bus
* 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6:
drm/i915: save/resume forcewake lock fixes
Revert "drm/i915: Kill GTT mappings when moving from GTT domain"
drm/i915: Apply HWSTAM workaround for BSD ring on SandyBridge
drm/i915: Call intel_enable_plane from i9xx_crtc_mode_set (again)
if cifs_get_root() fails, we end up with ->mount() returning NULL,
which is not what callers expect. Moreover, in case of superblock
reuse we end up leaking a superblock reference...
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
instead of calling it manually in case if cifs_read_super() fails
to set ->s_root, just call it from ->kill_sb(). cifs_put_super()
is gone now *and* we have cifs_sb shutdown and destruction done
after the superblock is gone from ->s_instances.
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
no need to wait until cifs_read_super() and we need it done
by the time cifs_mount() will be called.
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
pull mountdata allocation up, so that it won't stand in the way when
we lift cifs_mount() to location before sget().
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
To close sget() races we'll need to be able to set cifs_sb up before
we get the superblock, so we'll want to be able to do cifs_mount()
earlier. Fortunately, it's easy to do - setting ->s_maxbytes can
be done in cifs_read_super(), ditto for ->s_time_gran and as for
putting MS_POSIXACL into ->s_flags, we can mirror it in ->mnt_cifs_flags
until cifs_read_super() is called. Kill unused 'devname' argument,
while we are at it...
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
if cifs_sb allocation fails, we still need to drop nls we'd stashed
into volume_info - the one we would've copied to cifs_sb if we could
allocate the latter.
Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Suresh Siddha
Linus Torvalds
Steve French
Thomas Gleixner
Al Viro