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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-10-22 10:00:05 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-10-23 07:51:17 -0700 |
| commit | b2c4623dcd07af4b8ae3b56ae5f879e281c7b4f8 (patch) | |
| tree | 8a0aaf80f950011fafb6743d42457a22412ae6dd /kernel/rcu/tree.c | |
| parent | f114040e3ea6e07372334ade75d1ee0775c355e1 (diff) | |
rcu: More on deadlock between CPU hotplug and expedited grace periods
Commit dd56af42bd82 (rcu: Eliminate deadlock between CPU hotplug and
expedited grace periods) was incomplete. Although it did eliminate
deadlocks involving synchronize_sched_expedited()'s acquisition of
cpu_hotplug.lock via get_online_cpus(), it did nothing about the similar
deadlock involving acquisition of this same lock via put_online_cpus().
This deadlock became apparent with testing involving hibernation.
This commit therefore changes put_online_cpus() acquisition of this lock
to be conditional, and increments a new cpu_hotplug.puts_pending field
in case of acquisition failure. Then cpu_hotplug_begin() checks for this
new field being non-zero, and applies any changes to cpu_hotplug.refcount.
Reported-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'kernel/rcu/tree.c')
0 files changed, 0 insertions, 0 deletions