4.14-stable review patch. If anyone has any objections, please let me know.
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From: Maninder Singh maninder1.s@samsung.com
[ Upstream commit 299815a4fba9f3c7a81434dba0072148f1690608 ]
This patch fixes commit 5f48f0bd4e36 ("mm, page_owner: skip unnecessary stack_trace entries").
Because if we skip first two entries then logic of checking count value as 2 for recursion is broken and code will go in one depth recursion.
so we need to check only one call of _RET_IP(__set_page_owner) while checking for recursion.
Current Backtrace while checking for recursion:-
(save_stack) from (__set_page_owner) // (But recursion returns true here) (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) // recursion should return true here (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask+) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist)
Correct Backtrace with fix:
(save_stack) from (__set_page_owner) // recursion returned true here (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask+) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist)
Link: http://lkml.kernel.org/r/1521607043-34670-1-git-send-email-maninder1.s@samsu... Fixes: 5f48f0bd4e36 ("mm, page_owner: skip unnecessary stack_trace entries") Signed-off-by: Maninder Singh maninder1.s@samsung.com Signed-off-by: Vaneet Narang v.narang@samsung.com Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Michal Hocko mhocko@suse.com Cc: Oscar Salvador osalvador@techadventures.net Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Ayush Mittal ayush.m@samsung.com Cc: Prakash Gupta guptap@codeaurora.org Cc: Vinayak Menon vinmenon@codeaurora.org Cc: Vasyl Gomonovych gomonovych@gmail.com Cc: Amit Sahrawat a.sahrawat@samsung.com Cc: pankaj.m@samsung.com Cc: Vaneet Narang v.narang@samsung.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/page_owner.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -123,13 +123,13 @@ void __reset_page_owner(struct page *pag static inline bool check_recursive_alloc(struct stack_trace *trace, unsigned long ip) { - int i, count; + int i;
if (!trace->nr_entries) return false;
- for (i = 0, count = 0; i < trace->nr_entries; i++) { - if (trace->entries[i] == ip && ++count == 2) + for (i = 0; i < trace->nr_entries; i++) { + if (trace->entries[i] == ip) return true; }