4.14.63-rt41-rc2 stable review patch. If anyone has any objections, please let me know.
------------------ From: Julia Cartwright <[email protected]> [ Upstream commit afa4c06b89a3c0fb7784ff900ccd707bef519cb7 ] The mainline implementation of read_seqbegin() orders prior loads w.r.t. the read-side critical section. Fixup the RT writer-boosting implementation to provide the same guarantee. Also, while we're here, update the usage of ACCESS_ONCE() to use READ_ONCE(). Fixes: e69f15cf77c23 ("seqlock: Prevent rt starvation") Cc: [email protected] Signed-off-by: Julia Cartwright <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> --- include/linux/seqlock.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index a59751276b94..107079a2d7ed 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -462,6 +462,7 @@ static inline unsigned read_seqbegin(seqlock_t *sl) spin_unlock_wait(&sl->lock); goto repeat; } + smp_rmb(); return ret; } #endif -- 2.18.0
