This is a note to let you know that I've just added the patch titled
mm/migrate: fix refcount handling when !hugepage_migration_supported()
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-migrate-fix-refcount-handling-when-hugepage_migration_supported.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 30809f559a0d348c2dfd7ab05e9a451e2384962e Mon Sep 17 00:00:00 2001
From: Punit Agrawal <punit.agrawal@xxxxxxx>
Date: Fri, 2 Jun 2017 14:46:40 -0700
Subject: mm/migrate: fix refcount handling when !hugepage_migration_supported()
From: Punit Agrawal <punit.agrawal@xxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx: remove dead comment, per Naoya]
Link: http://lkml.kernel.org/r/20170525135146.32011-1-punit.agrawal@xxxxxxx
Reported-by: Manoj Iyer <manoj.iyer@xxxxxxxxxxxxx>
Tested-by: Manoj Iyer <manoj.iyer@xxxxxxxxxxxxx>
Suggested-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1570,12 +1570,8 @@ 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 {
Patches currently in stable-queue which might be from punit.agrawal@xxxxxxx are
queue-3.18/mm-migrate-fix-refcount-handling-when-hugepage_migration_supported.patch