Hello, Ingo,
This series contains two small fixes for regressions introduced during
the past merge window:
1. Recent versions of gcc are fatally confused by use of a const
int variable for array bounds in inline functions, one of which
was introduced by 114b7fd4b (rcu: Create rcu_sync infrastructure).
For more information on the gcc bug, see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
This workaround for that gcc bug, courtesy of Oleg Nesterov,
simply substitutes the constant expression for the two uses of
the const int variable.
2. Commit 2cd6ffafec06 (rcu: Extend expedited funnel locking
to rcu_data structure) extended contention-reducing
funnel locking from the rcu_node structures to the rcu_data
structures, but failed to create a separate lock class for the
rcu_sched_data structures, which is needed due to the fact that
synchronize_rcu_expedited() invokes synchronize_sched_expedited().
In the absence of this separate lock class, lockdep can give
false-positive splats. This commit therefore creates the
required lock class so that lockdep can see that there is in
fact no deadlock.
Both fixes have been exposed to -next and 0day Test Robot testing.
These changes are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git for-mingo
for you to fetch changes up to 19a5ecde086a6a5287978b12ae948fa691b197b7:
rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex (2015-09-20
21:01:22 -0700)
----------------------------------------------------------------
Oleg Nesterov (1):
rcu: Change _wait_rcu_gp() to work around GCC bug 67055
Paul E. McKenney (1):
rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex
include/linux/rcupdate.h | 11 +++++------
kernel/rcu/tree.c | 5 +++++
2 files changed, 10 insertions(+), 6 deletions(-)
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