Messages in this thread |  | | Date | Fri, 15 Mar 2024 14:07:45 +0100 | | Subject | Re: [PATCH] mm,page_owner: Fix recursion | | From | Vlastimil Babka <> |
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On 3/14/24 00:42, Oscar Salvador wrote: > Prior to 217b2119b9e2 ("mm,page_owner: implement the tracking of the stacks count") > the only place where page_owner could potentially go into recursion due to > its need of allocating more memory was in save_stack(), which ends up calling > into stackdepot code with the possibility of allocating memory. > > We made sure to guard against that by signaling that the current task was > already in page_owner code, so in case a recursion attempt was made, we > could catch that and return dummy_handle. > > After above commit, a new place in page_owner code was introduced where we > could allocate memory, meaning we could go into recursion would we take that > path. > > Make sure to signal that we are in page_owner in that codepath as well. > Move the guard code into two helpers {un}set_current_in_page_owner() > and use them prior to calling in the two functions that might allocate > memory. > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > Fixes: 217b2119b9e2 ("mm,page_owner: implement the tracking of the stacks count") > --- > mm/page_owner.c | 30 +++++++++++++++++++++--------- > 1 file changed, 21 insertions(+), 9 deletions(-) > > @@ -292,7 +302,9 @@ noinline void __set_page_owner(struct page *page, unsigned short order, > return; > __set_page_owner_handle(page_ext, handle, order, gfp_mask); > page_ext_put(page_ext); > + set_current_in_page_owner(); > inc_stack_record_count(handle, gfp_mask); > + unset_current_in_page_owner();
This is because of the kmalloc() in add_stack_record_to_list() right? Why not wrap just that then?
> } > > void __set_page_owner_migrate_reason(struct page *page, int reason)
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