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authorPunit Agrawal <punit.agrawal@arm.com>2017-06-02 14:46:40 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-07 12:07:49 +0200
commitd494cab70697413fe1a1b6ae57e4ba18a5e43e36 (patch)
tree5d61b43fdbf344b85d6eb1c981d1a3368ca850bf
parent7d8ef0e0bc1e25cc23f6012aacafe3b28e8c01f7 (diff)
downloadlinux-aarch64-d494cab70697413fe1a1b6ae57e4ba18a5e43e36.tar.gz
mm/migrate: fix refcount handling when !hugepage_migration_supported()
commit 30809f559a0d348c2dfd7ab05e9a451e2384962e upstream. On failing to migrate a page, soft_offline_huge_page() performs the necessary update to the hugepage ref-count. But when !hugepage_migration_supported() , unmap_and_move_hugepage() also decrements the page ref-count for the hugepage. The combined behaviour leaves the ref-count in an inconsistent state. This leads to soft lockups when running the overcommitted hugepage test from mce-tests suite. Soft offlining pfn 0x83ed600 at process virtual address 0x400000000000 soft offline: 0x83ed600: migration failed 1, type 1fffc00000008008 (uptodate|head) INFO: rcu_preempt detected stalls on CPUs/tasks: Tasks blocked on level-0 rcu_node (CPUs 0-7): P2715 (detected by 7, t=5254 jiffies, g=963, c=962, q=321) thugetlb_overco R running task 0 2715 2685 0x00000008 Call trace: dump_backtrace+0x0/0x268 show_stack+0x24/0x30 sched_show_task+0x134/0x180 rcu_print_detail_task_stall_rnp+0x54/0x7c rcu_check_callbacks+0xa74/0xb08 update_process_times+0x34/0x60 tick_sched_handle.isra.7+0x38/0x70 tick_sched_timer+0x4c/0x98 __hrtimer_run_queues+0xc0/0x300 hrtimer_interrupt+0xac/0x228 arch_timer_handler_phys+0x3c/0x50 handle_percpu_devid_irq+0x8c/0x290 generic_handle_irq+0x34/0x50 __handle_domain_irq+0x68/0xc0 gic_handle_irq+0x5c/0xb0 Address this by changing the putback_active_hugepage() in soft_offline_huge_page() to putback_movable_pages(). This only triggers on systems that enable memory failure handling (ARCH_SUPPORTS_MEMORY_FAILURE) but not hugepage migration (!ARCH_ENABLE_HUGEPAGE_MIGRATION). I imagine this wasn't triggered as there aren't many systems running this configuration. [akpm@linux-foundation.org: remove dead comment, per Naoya] Link: http://lkml.kernel.org/r/20170525135146.32011-1-punit.agrawal@arm.com Reported-by: Manoj Iyer <manoj.iyer@canonical.com> Tested-by: Manoj Iyer <manoj.iyer@canonical.com> Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/memory-failure.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 19e796d36a62..4bd44803e366 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1587,12 +1587,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
if (ret) {
pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
pfn, ret, page->flags);
- /*
- * We know that soft_offline_huge_page() tries to migrate
- * only one hugepage pointed to by hpage, so we need not
- * run through the pagelist here.
- */
- putback_active_hugepage(hpage);
+ if (!list_empty(&pagelist))
+ putback_movable_pages(&pagelist);
if (ret > 0)
ret = -EIO;
} else {