This is a note to let you know that I've just added the patch titled
memfd: Use radix_tree_deref_slot_protected to avoid the warning.
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
memfd-use-radix_tree_deref_slot_protected-to-avoid-the-warning.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From zhongjiang@xxxxxxxxxx Tue Nov 19 05:57:26 2019
From: zhong jiang <zhongjiang@xxxxxxxxxx>
Date: Mon, 18 Nov 2019 11:26:09 +0800
Subject: memfd: Use radix_tree_deref_slot_protected to avoid the warning.
To: <sashal@xxxxxxxxxx>, <gregkh@xxxxxxxxxxxxxxxxxxx>, <stable@xxxxxxxxxxxxxxx>, <willy@xxxxxxxxxxxxx>
Cc: <linux-mm@xxxxxxxxx>, <yangyingliang@xxxxxxxxxx>
Message-ID: <20191118032610.182862-3-zhongjiang@xxxxxxxxxx>
From: zhong jiang <zhongjiang@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Fixes: eb4058d8daf8 ("memfd: Fix locking when tagging pins")
Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1862,7 +1862,7 @@ static void shmem_tag_pins(struct addres
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;
Patches currently in stable-queue which might be from zhongjiang@xxxxxxxxxx are
queue-4.4/misc-genwqe-should-return-proper-error-value.patch
queue-4.4/memfd-use-radix_tree_deref_slot_protected-to-avoid-the-warning.patch
