From: Andrew Morton <akpm@linux-foundation.org>
To: stable@vger.kernel.org,osalvador@suse.de,david@redhat.com,catalin.marinas@arm.com,lang.yu@amd.com,akpm@linux-foundation.org,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org
Subject: [patch 08/10] mm/kmemleak: avoid scanning potential huge holes
Date: Thu, 03 Feb 2022 20:49:37 -0800 [thread overview]
Message-ID: <20220204044938.34C78C340E9@smtp.kernel.org> (raw)
In-Reply-To: <20220203204836.88dcebe504f440686cc63a60@linux-foundation.org>
From: Lang Yu <lang.yu@amd.com>
Subject: mm/kmemleak: avoid scanning potential huge holes
When using devm_request_free_mem_region() and devm_memremap_pages() to add
ZONE_DEVICE memory, if requested free mem region's end pfn were huge(e.g.,
0x400000000), the node_end_pfn() will be also huge (see
move_pfn_range_to_zone()). Thus it creates a huge hole between
node_start_pfn() and node_end_pfn().
We found on some AMD APUs, amdkfd requested such a free mem region and
created a huge hole. In such a case, following code snippet was just
doing busy test_bit() looping on the huge hole.
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
struct page *page = pfn_to_online_page(pfn);
if (!page)
continue;
...
}
So we got a soft lockup:
watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
RIP: 0010:pfn_to_online_page+0x5/0xd0
Call Trace:
? kmemleak_scan+0x16a/0x440
kmemleak_write+0x306/0x3a0
? common_file_perm+0x72/0x170
full_proxy_write+0x5c/0x90
vfs_write+0xb9/0x260
ksys_write+0x67/0xe0
__x64_sys_write+0x1a/0x20
do_syscall_64+0x3b/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae
I did some tests with the patch.
(1) amdgpu module unloaded
before the patch:
real 0m0.976s
user 0m0.000s
sys 0m0.968s
after the patch:
real 0m0.981s
user 0m0.000s
sys 0m0.973s
(2) amdgpu module loaded
before the patch:
real 0m35.365s
user 0m0.000s
sys 0m35.354s
after the patch:
real 0m1.049s
user 0m0.000s
sys 0m1.042s
Link: https://lkml.kernel.org/r/20211108140029.721144-1-lang.yu@amd.com
Signed-off-by: Lang Yu <lang.yu@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/kmemleak.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
--- a/mm/kmemleak.c~mm-kmemleak-avoid-scanning-potential-huge-holes
+++ a/mm/kmemleak.c
@@ -1410,7 +1410,8 @@ static void kmemleak_scan(void)
{
unsigned long flags;
struct kmemleak_object *object;
- int i;
+ struct zone *zone;
+ int __maybe_unused i;
int new_leaks = 0;
jiffies_last_scan = jiffies;
@@ -1450,9 +1451,9 @@ static void kmemleak_scan(void)
* Struct page scanning for each node.
*/
get_online_mems();
- for_each_online_node(i) {
- unsigned long start_pfn = node_start_pfn(i);
- unsigned long end_pfn = node_end_pfn(i);
+ for_each_populated_zone(zone) {
+ unsigned long start_pfn = zone->zone_start_pfn;
+ unsigned long end_pfn = zone_end_pfn(zone);
unsigned long pfn;
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
@@ -1461,8 +1462,8 @@ static void kmemleak_scan(void)
if (!page)
continue;
- /* only scan pages belonging to this node */
- if (page_to_nid(page) != i)
+ /* only scan pages belonging to this zone */
+ if (page_zone(page) != zone)
continue;
/* only scan if page is in use */
if (page_count(page) == 0)
_
next prev parent reply other threads:[~2022-02-04 4:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 4:48 incoming Andrew Morton
2022-02-04 4:49 ` [patch 01/10] Revert "mm/page_isolation: unset migratetype directly for non Buddy page" Andrew Morton
2022-02-04 4:49 ` [patch 02/10] mm/debug_vm_pgtable: remove pte entry from the page table Andrew Morton
2022-02-04 4:49 ` [patch 03/10] mm/page_table_check: use unsigned long for page counters and cleanup Andrew Morton
2022-02-04 4:49 ` [patch 04/10] mm/khugepaged: unify collapse pmd clear, flush and free Andrew Morton
2022-02-04 4:49 ` [patch 05/10] mm/page_table_check: check entries at pmd levels Andrew Morton
2022-02-04 4:49 ` [patch 06/10] mm/pgtable: define pte_index so that preprocessor could recognize it Andrew Morton
2022-02-04 4:49 ` [patch 07/10] ipc/sem: do not sleep with a spin lock held Andrew Morton
2022-02-04 4:49 ` Andrew Morton [this message]
2022-02-04 4:49 ` [patch 09/10] MAINTAINERS: update rppt's email Andrew Morton
2022-02-04 4:49 ` [patch 10/10] kselftest/vm: revert "tools/testing/selftests/vm/userfaultfd.c: use swap() to make code cleaner" Andrew Morton
2022-02-04 17:56 ` [patch 01/10] Revert "mm/page_isolation: unset migratetype directly for non Buddy page" Andrew Morton
2022-02-04 17:56 ` [patch 02/10] mm/debug_vm_pgtable: remove pte entry from the page table Andrew Morton
2022-02-04 17:56 ` [patch 03/10] mm/page_table_check: use unsigned long for page counters and cleanup Andrew Morton
2022-02-04 17:56 ` [patch 04/10] mm/khugepaged: unify collapse pmd clear, flush and free Andrew Morton
2022-02-04 17:56 ` [patch 05/10] mm/page_table_check: check entries at pmd levels Andrew Morton
2022-02-04 17:57 ` [patch 06/10] mm/pgtable: define pte_index so that preprocessor could recognize it Andrew Morton
2022-02-04 17:57 ` [patch 07/10] ipc/sem: do not sleep with a spin lock held Andrew Morton
2022-02-04 17:57 ` [patch 08/10] mm/kmemleak: avoid scanning potential huge holes Andrew Morton
2022-02-04 17:57 ` [patch 09/10] MAINTAINERS: update rppt's email Andrew Morton
2022-02-04 17:57 ` [patch 10/10] kselftest/vm: revert "tools/testing/selftests/vm/userfaultfd.c: use swap() to make code cleaner" Andrew Morton
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