From: Oleg Nesterov <o...@redhat.com>
This is the temporary ugly hack which will be reverted later. We only
need it to ensure that the next patch will not break "change sb_writers
to use percpu_rw_semaphore" patches routed via the VFS tree.
The alloc_super()->destroy_super() error path assumes that it is safe
to call percpu_free_rwsem() after kzalloc() without percpu_init_rwsem(),
so let's not disappoint it.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
---
kernel/locking/percpu-rwsem.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 652a8ee8efe9..67a758df1d7c 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -25,6 +25,13 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *brw,
void percpu_free_rwsem(struct percpu_rw_semaphore *brw)
{
+ /*
+ * XXX: temporary kludge. The error path in alloc_super()
+ * assumes that percpu_free_rwsem() is safe after kzalloc().
+ */
+ if (!brw->fast_read_ctr)
+ return;
+
free_percpu(brw->fast_read_ctr);
brw->fast_read_ctr = NULL; /* catch use after free bugs */
}
--
1.8.1.5
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