]> git.itanic.dy.fi Git - linux-stable/commitdiff
mm,page_owner: fix printing of stack records
authorOscar Salvador <osalvador@suse.de>
Thu, 4 Apr 2024 07:07:02 +0000 (09:07 +0200)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 16 Apr 2024 22:39:49 +0000 (15:39 -0700)
When seq_* code sees that its buffer overflowed, it re-allocates a bigger
onecand calls seq_operations->start() callback again.  stack_start()
naively though that if it got called again, it meant that the old record
got already printed so it returned the next object, but that is not true.

The consequence of that is that every time stack_stop() -> stack_start()
get called because we needed a bigger buffer, stack_start() will skip
entries, and those will not be printed.

Fix it by not advancing to the next object in stack_start().

Link: https://lkml.kernel.org/r/20240404070702.2744-5-osalvador@suse.de
Fixes: 765973a09803 ("mm,page_owner: display all stacks and their count")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/page_owner.c

index b4476f45b376e177bdb401f23a4ba97deaa51eb5..9bef0b4428634bccfb35b245d6e2dfe2905cefcd 100644 (file)
@@ -872,13 +872,11 @@ static void *stack_start(struct seq_file *m, loff_t *ppos)
                 * value of stack_list.
                 */
                stack = smp_load_acquire(&stack_list);
+               m->private = stack;
        } else {
                stack = m->private;
-               stack = stack->next;
        }
 
-       m->private = stack;
-
        return stack;
 }