Patch "mm: memory-failure: fix unexpected return value in soft_offline_page()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    mm: memory-failure: fix unexpected return value in soft_offline_page()

to the 5.15-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:
     mm-memory-failure-fix-unexpected-return-value-in-sof.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e877c821dcab90275d57877da3ad993985153081
Author: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Date:   Tue Jun 27 19:28:08 2023 +0800

    mm: memory-failure: fix unexpected return value in soft_offline_page()
    
    [ Upstream commit e2c1ab070fdc81010ec44634838d24fce9ff9e53 ]
    
    When page_handle_poison() fails to handle the hugepage or free page in
    retry path, soft_offline_page() will return 0 while -EBUSY is expected in
    this case.
    
    Consequently the user will think soft_offline_page succeeds while it in
    fact failed.  So the user will not try again later in this case.
    
    Link: https://lkml.kernel.org/r/20230627112808.1275241-1-linmiaohe@xxxxxxxxxx
    Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages")
    Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
    Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
    Cc: <stable@xxxxxxxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 69d22af10adfc..bcd71d8736be5 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2284,10 +2284,13 @@ int soft_offline_page(unsigned long pfn, int flags)
 	if (ret > 0) {
 		ret = soft_offline_in_use_page(page);
 	} else if (ret == 0) {
-		if (!page_handle_poison(page, true, false) && try_again) {
-			try_again = false;
-			flags &= ~MF_COUNT_INCREASED;
-			goto retry;
+		if (!page_handle_poison(page, true, false)) {
+			if (try_again) {
+				try_again = false;
+				flags &= ~MF_COUNT_INCREASED;
+				goto retry;
+			}
+			ret = -EBUSY;
 		}
 	}