Re: [PATCH v1 2/2] mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous()
From: Shile Zhang
Date: Wed Apr 01 2020 - 09:59:50 EST
On 2020/4/1 18:41, David Hildenbrand wrote:
Without CONFIG_PREEMPT, it can happen that we get soft lockups detected,
e.g., while booting up.
[ 105.608900] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1]
[ 105.608933] Modules linked in:
[ 105.608933] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-next-20200331+ #4
[ 105.608933] Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
[ 105.608933] RIP: 0010:__pageblock_pfn_to_page+0x134/0x1c0
[ 105.608933] Code: 85 c0 74 71 4a 8b 04 d0 48 85 c0 74 68 48 01 c1 74 63 f6 01 04 74 5e 48 c1 e7 06 4c 8b 05 cc 991
[ 105.608933] RSP: 0000:ffffb6d94000fe60 EFLAGS: 00010286 ORIG_RAX: ffffffffffffff13
[ 105.608933] RAX: fffff81953250000 RBX: 000000000a4c9600 RCX: ffff8fe9ff7c1990
[ 105.608933] RDX: ffff8fe9ff7dab80 RSI: 000000000a4c95ff RDI: 0000000293250000
[ 105.608933] RBP: ffff8fe9ff7dab80 R08: fffff816c0000000 R09: 0000000000000008
[ 105.608933] R10: 0000000000000014 R11: 0000000000000014 R12: 0000000000000000
[ 105.608933] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 105.608933] FS: 0000000000000000(0000) GS:ffff8fe1ff400000(0000) knlGS:0000000000000000
[ 105.608933] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 105.608933] CR2: 000000000f613000 CR3: 00000088cf20a000 CR4: 00000000000006f0
[ 105.608933] Call Trace:
[ 105.608933] set_zone_contiguous+0x56/0x70
[ 105.608933] page_alloc_init_late+0x166/0x176
[ 105.608933] kernel_init_freeable+0xfa/0x255
[ 105.608933] ? rest_init+0xaa/0xaa
[ 105.608933] kernel_init+0xa/0x106
[ 105.608933] ret_from_fork+0x35/0x40
The issue becomes visible when having a lot of memory (e.g., 4TB)
assigned to a single NUMA node - a system that can easily be created
using QEMU. Inside VMs on a hypervisor with quite some memory
overcommit, this is fairly easy to trigger.
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Cc: Shile Zhang <shile.zhang@xxxxxxxxxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Alexander Duyck <alexander.duyck@xxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/page_alloc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 084cabffc90d..cc4f07d52939 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1607,6 +1607,7 @@ void set_zone_contiguous(struct zone *zone)
if (!__pageblock_pfn_to_page(block_start_pfn,
block_end_pfn, zone))
return;
+ cond_resched();
}
/* We confirm that there is no hole */
Reviewed-by: Shile Zhang<shile.zhang@xxxxxxxxxxxxxxxxx>