diff options
| author | Lang Yu <lang.yu@amd.com> | 2022-02-03 20:49:37 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-02-04 09:25:05 -0800 |
| commit | c10a0f877fe007021d70f9cada240f42adc2b5db (patch) | |
| tree | 8bf9f7e41f568a786715a365cb6c30c98af0687d | |
| parent | 520ba724061cef59763e2b6f5b26e8387c2e5822 (diff) | |
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/kmemleak.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index dc3758fdba68..7580baa76af1 100644 --- a/mm/kmemleak.c +++ b/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) |