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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-09-18 17:45:22 +0200 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-10-06 20:16:42 +0200 |
commit | 7f5f873c6a0772970d5fee1f364231207051ecd8 (patch) | |
tree | ca06a26b0a485a63cf42417a12dea443a0df103c /kernel/rcu/tree.c | |
parent | rcu: Remove deprecated rcu_lockdep_assert() (diff) | |
download | linux-7f5f873c6a0772970d5fee1f364231207051ecd8.tar.xz linux-7f5f873c6a0772970d5fee1f364231207051ecd8.zip |
rculist: Use WRITE_ONCE() when deleting from reader-visible list
The various RCU list-deletion macros (list_del_rcu(),
hlist_del_init_rcu(), hlist_del_rcu(), hlist_bl_del_init_rcu(),
hlist_bl_del_rcu(), hlist_nulls_del_init_rcu(), and hlist_nulls_del_rcu())
do plain stores into the ->next pointer of the preceding list elemment.
Unfortunately, the compiler is within its rights to (for example) use
byte-at-a-time writes to update the pointer, which would fatally confuse
concurrent readers. This patch therefore adds the needed WRITE_ONCE()
macros.
KernelThreadSanitizer (KTSAN) reported the __hlist_del() issue, which
is a problem when __hlist_del() is invoked by hlist_del_rcu().
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcu/tree.c')
0 files changed, 0 insertions, 0 deletions