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| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2018-08-23 17:00:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-23 18:48:43 -0700 |
| commit | d4ae9916ea2947341180d2b538f48875ff393a86 (patch) | |
| tree | e478e5e6e84de25fade8f2995c9ee49cacd5a488 /mm/migrate.c | |
| parent | 6bc9b56433b76e40d11099338d27fbc5cd2935ca (diff) | |
| download | linux-d4ae9916ea2947341180d2b538f48875ff393a86.tar.gz | |
mm: soft-offline: close the race against page allocation
A process can be killed with SIGBUS(BUS_MCEERR_AR) when it tries to allocate a page that was just freed on the way of soft-offline. This is undesirable because soft-offline (which is about corrected error) is less aggressive than hard-offline (which is about uncorrected error), and we can make soft-offline fail and keep using the page for good reason like "system is busy." Two main changes of this patch are: - setting migrate type of the target page to MIGRATE_ISOLATE. As done in free_unref_page_commit(), this makes kernel bypass pcplist when freeing the page. So we can assume that the page is in freelist just after put_page() returns, - setting PG_hwpoison on free page under zone->lock which protects freelists, so this allows us to avoid setting PG_hwpoison on a page that is decided to be allocated soon. [akpm@linux-foundation.org: tweak set_hwpoison_free_buddy_page() comment] Link: http://lkml.kernel.org/r/1531452366-11661-3-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com> Tested-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <zy.zhengyi@alibaba-inc.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 91a99457127c..d6a2e89b086a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1212,7 +1212,7 @@ out: * intentionally. Although it's rather weird, * it's how HWPoison flag works at the moment. */ - if (!test_set_page_hwpoison(page)) + if (set_hwpoison_free_buddy_page(page)) num_poisoned_pages_inc(); } } else { |