| From 30809f559a0d348c2dfd7ab05e9a451e2384962e Mon Sep 17 00:00:00 2001 |
| From: Punit Agrawal <punit.agrawal@arm.com> |
| Date: Fri, 2 Jun 2017 14:46:40 -0700 |
| Subject: mm/migrate: fix refcount handling when !hugepage_migration_supported() |
| |
| From: Punit Agrawal <punit.agrawal@arm.com> |
| |
| 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> |
| |
| --- |
| mm/memory-failure.c | 8 ++------ |
| 1 file changed, 2 insertions(+), 6 deletions(-) |
| |
| --- a/mm/memory-failure.c |
| +++ b/mm/memory-failure.c |
| @@ -1587,12 +1587,8 @@ static int soft_offline_huge_page(struct |
| 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 { |