| Message ID | 20191118032610.182862-3-zhongjiang@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [4.4] memfd: Use radix_tree_deref_slot_protected to avoid the warning. | expand |
On Mon, Nov 18, 2019 at 11:26:09AM +0800, zhong jiang wrote: > The commit eb4058d8daf8 ("memfd: Fix locking when tagging pins") > introduces the following warning messages. > > *WARNING: suspicious RCU usage in memfd_wait_for_pins* > > It is because we still use radix_tree_deref_slot without read_rcu_lock. > We should use radix_tree_deref_slot_protected instead in the case. > > Cc: stable@vger.kernel.org > Fixes: eb4058d8daf8 ("memfd: Fix locking when tagging pins") > Signed-off-by: zhong jiang <zhongjiang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff --git a/mm/shmem.c b/mm/shmem.c index 62668379623b..e40239bf6dfe 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1862,7 +1862,7 @@ static void shmem_tag_pins(struct address_space *mapping) spin_lock_irq(&mapping->tree_lock); restart: radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { - page = radix_tree_deref_slot(slot); + page = radix_tree_deref_slot_protected(slot, &mapping->tree_lock); if (!page || radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) goto restart;
The commit eb4058d8daf8 ("memfd: Fix locking when tagging pins") introduces the following warning messages. *WARNING: suspicious RCU usage in memfd_wait_for_pins* It is because we still use radix_tree_deref_slot without read_rcu_lock. We should use radix_tree_deref_slot_protected instead in the case. Cc: stable@vger.kernel.org Fixes: eb4058d8daf8 ("memfd: Fix locking when tagging pins") Signed-off-by: zhong jiang <zhongjiang@huawei.com> --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)