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authorManinder Singh <maninder1.s@samsung.com>2018-03-29 02:01:05 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-03-29 02:42:05 +0300
commit299815a4fba9f3c7a81434dba0072148f1690608 (patch)
tree3475fab8b3c15a02296315de07f13ff16f09da50 /mm
parent3d942ee079b917b24e2a0c5f18d35ac8ec9fee48 (diff)
downloadlinux-299815a4fba9f3c7a81434dba0072148f1690608.tar.xz
mm/page_owner: fix recursion bug after changing skip entries
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@samsung.com 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>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_owner.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 9886c6073828..7172e0a80e13 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -123,13 +123,13 @@ void __reset_page_owner(struct page *page, unsigned int order)
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;
}