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mm: check_new_page_bad() directly returns in __PG_HWPOISON case

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Currently we check page->flags twice for "HWPoisoned" case of
check_new_page_bad(), which can cause a race with unpoisoning.

This race unnecessarily taints kernel with "BUG: Bad page state".
check_new_page_bad() is the only caller of bad_page() which is
interested in __PG_HWPOISON, so let's move the hwpoison related code in
bad_page() to it.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Naoya Horiguchi <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Naoya Horiguchi
2016-05-20 17:58:30 -07:00
committed by Linus Torvalds
parent 29b52de182
commit e570f56ccc
1 changed files with 3 additions and 6 deletions
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mm/page_alloc.c
+3 -6
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@@ -522,12 +522,6 @@ static void bad_page(struct page *page, const char *reason,
static unsigned long nr_shown;
static unsigned long nr_unshown;
/* Don't complain about poisoned pages */
if (PageHWPoison(page)) {
page_mapcount_reset(page); /* remove PageBuddy */
return;
}
/*
* Allow a burst of 60 reports, then keep quiet for that minute;
* or allow a steady drip of one report per second.
@@ -1654,6 +1648,9 @@ static void check_new_page_bad(struct page *page)
if (unlikely(page->flags & __PG_HWPOISON)) {
bad_reason = "HWPoisoned (hardware-corrupted)";
bad_flags = __PG_HWPOISON;
/* Don't complain about hwpoisoned pages */
page_mapcount_reset(page); /* remove PageBuddy */
return;
}
if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";