Maninder Singh d2a5d00dcd mm/page_owner: fix recursion bug after changing skip entries
[ 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@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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-30 07:52:21 +02:00
2018-05-25 16:18:02 +02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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