diff options
| author | Miaohe Lin <linmiaohe@huawei.com> | 2023-07-27 14:56:41 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-04 23:03:41 +0300 |
| commit | f29623e4a599c295cc8f518c8e4bb7848581a14d (patch) | |
| tree | 6c3ec94fa281458632d9734743a7590267796a3d /mm | |
| parent | f985fc322063c73916a0d5b6b3fcc6db2ba5792c (diff) | |
| download | linux-f29623e4a599c295cc8f518c8e4bb7848581a14d.tar.xz | |
mm: memory-failure: fix potential unexpected return value from unpoison_memory()
If unpoison_memory() fails to clear page hwpoisoned flag, return value ret
is expected to be -EBUSY. But when get_hwpoison_page() returns 1 and
fails to clear page hwpoisoned flag due to races, return value will be
unexpected 1 leading to users being confused. And there's a code smell
that the variable "ret" is used not only to save the return value of
unpoison_memory(), but also the return value from get_hwpoison_page().
Make a further cleanup by using another auto-variable solely to save the
return value of get_hwpoison_page() as suggested by Naoya.
Link: https://lkml.kernel.org/r/20230727115643.639741-3-linmiaohe@huawei.com
Fixes: bf181c582588 ("mm/hwpoison: fix unpoison_memory()")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory-failure.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ece5d481b5ff..b32d370b5d43 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2466,7 +2466,7 @@ int unpoison_memory(unsigned long pfn) { struct folio *folio; struct page *p; - int ret = -EBUSY; + int ret = -EBUSY, ghp; unsigned long count = 1; bool huge = false; static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, @@ -2514,29 +2514,28 @@ int unpoison_memory(unsigned long pfn) if (folio_test_slab(folio) || PageTable(&folio->page) || folio_test_reserved(folio)) goto unlock_mutex; - ret = get_hwpoison_page(p, MF_UNPOISON); - if (!ret) { + ghp = get_hwpoison_page(p, MF_UNPOISON); + if (!ghp) { if (PageHuge(p)) { huge = true; count = folio_free_raw_hwp(folio, false); - if (count == 0) { - ret = -EBUSY; + if (count == 0) goto unlock_mutex; - } } ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY; - } else if (ret < 0) { - if (ret == -EHWPOISON) { + } else if (ghp < 0) { + if (ghp == -EHWPOISON) { ret = put_page_back_buddy(p) ? 0 : -EBUSY; - } else + } else { + ret = ghp; unpoison_pr_info("Unpoison: failed to grab page %#lx\n", pfn, &unpoison_rs); + } } else { if (PageHuge(p)) { huge = true; count = folio_free_raw_hwp(folio, false); if (count == 0) { - ret = -EBUSY; folio_put(folio); goto unlock_mutex; } |