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authorOscar Salvador <osalvador@suse.de>2024-04-09 15:17:15 +0200
committerAndrew Morton <akpm@linux-foundation.org>2024-04-17 00:39:51 +0200
commit0b2cf0a45e06d9538a2371f90150297a87b20eea (patch)
treef3cb26ea80ee0551477fc25d4c81dd1f3471741a /mm/page_owner.c
parentSquashfs: check the inode number is not the invalid value of zero (diff)
downloadlinux-0b2cf0a45e06d9538a2371f90150297a87b20eea.tar.xz
linux-0b2cf0a45e06d9538a2371f90150297a87b20eea.zip
mm,page_owner: defer enablement of static branch
Kefeng Wang reported that he was seeing some memory leaks with kmemleak with page_owner enabled. The reason is that we enable the page_owner_inited static branch and then proceed with the linking of stack_list struct to dummy_stack, which means that exists a race window between these two steps where we can have pages already being allocated calling add_stack_record_to_list(), allocating objects and linking them to stack_list, but then we set stack_list pointing to dummy_stack in init_page_owner. Which means that the objects that have been allocated during that time window are unreferenced and lost. Fix this by deferring the enablement of the branch until we have properly set up the list. Link: https://lkml.kernel.org/r/20240409131715.13632-1-osalvador@suse.de Fixes: 4bedfb314bdd ("mm,page_owner: maintain own list of stack_records structs") Signed-off-by: Oscar Salvador <osalvador@suse.de> Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> Closes: https://lore.kernel.org/linux-mm/74b147b0-718d-4d50-be75-d6afc801cd24@huawei.com/ Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--mm/page_owner.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 9bef0b442863..742f432e5bf0 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -118,7 +118,6 @@ static __init void init_page_owner(void)
register_dummy_stack();
register_failure_stack();
register_early_stack();
- static_branch_enable(&page_owner_inited);
init_early_allocated_pages();
/* Initialize dummy and failure stacks and link them to stack_list */
dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle);
@@ -129,6 +128,7 @@ static __init void init_page_owner(void)
refcount_set(&failure_stack.stack_record->count, 1);
dummy_stack.next = &failure_stack;
stack_list = &dummy_stack;
+ static_branch_enable(&page_owner_inited);
}
struct page_ext_operations page_owner_ops = {