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mm/kmemleak: avoid scanning potential huge holes
commit c10a0f877f
upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
65a4863a4e
commit
a5389c8099
1 changed files with 7 additions and 6 deletions
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@ -1403,7 +1403,8 @@ static void kmemleak_scan(void)
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{
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unsigned long flags;
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struct kmemleak_object *object;
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int i;
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struct zone *zone;
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int __maybe_unused i;
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int new_leaks = 0;
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jiffies_last_scan = jiffies;
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@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
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* Struct page scanning for each node.
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*/
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get_online_mems();
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for_each_online_node(i) {
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unsigned long start_pfn = node_start_pfn(i);
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unsigned long end_pfn = node_end_pfn(i);
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for_each_populated_zone(zone) {
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unsigned long start_pfn = zone->zone_start_pfn;
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unsigned long end_pfn = zone_end_pfn(zone);
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unsigned long pfn;
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for (pfn = start_pfn; pfn < end_pfn; pfn++) {
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@ -1454,8 +1455,8 @@ static void kmemleak_scan(void)
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if (!page)
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continue;
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/* only scan pages belonging to this node */
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if (page_to_nid(page) != i)
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/* only scan pages belonging to this zone */
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if (page_zone(page) != zone)
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continue;
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/* only scan if page is in use */
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if (page_count(page) == 0)
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