Linux kernel modifications for the Kernel Hacking exam
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Yang Shi df9576def0 Revert "kmemleak: allow to coexist with fault injection"
When running ltp's oom test with kmemleak enabled, the below warning was
triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
passed in:

  WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50
  Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata
  CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50
  ...
   kmemleak_alloc+0x4e/0xb0
   kmem_cache_alloc+0x2a7/0x3e0
   mempool_alloc_slab+0x2d/0x40
   mempool_alloc+0x118/0x2b0
   bio_alloc_bioset+0x19d/0x350
   get_swap_bio+0x80/0x230
   __swap_writepage+0x5ff/0xb20

The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak
has __GFP_NOFAIL set all the time due to d9570ee3bd ("kmemleak:
allow to coexist with fault injection").  But, it doesn't make any sense
to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same
time.

According to the discussion on the mailing list, the commit should be
reverted for short term solution.  Catalin Marinas would follow up with
a better solution for longer term.

The failure rate of kmemleak metadata allocation may increase in some
circumstances, but this should be expected side effect.

Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d9570ee3bd ("kmemleak: allow to coexist with fault injection")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03 07:02:00 -07:00
arch add swiotlb support to arm 2019-08-02 08:44:33 -07:00
block for-linus-20190726-2 2019-07-26 19:20:34 -07:00
certs
crypto
Documentation HMM patches for 5.3-rc 2019-07-30 12:54:44 -07:00
drivers Power management fix for 5.3-rc3 2019-08-02 08:55:28 -07:00
fs Fix gfs2 cluster coherency bug 2019-08-02 09:02:58 -07:00
include A few fixes for code that came in during the merge window or 2019-08-02 08:47:28 -07:00
init
ipc
kernel kernel/signal.c: fix a kernel-doc markup 2019-08-03 07:02:00 -07:00
lib test_firmware: fix a memory leak bug 2019-07-25 14:39:52 +02:00
LICENSES
mm Revert "kmemleak: allow to coexist with fault injection" 2019-08-03 07:02:00 -07:00
net
samples
scripts Kbuild fixes for v5.3 2019-07-28 10:35:04 -07:00
security meminit fix 2019-07-28 12:33:15 -07:00
sound sound fixes for 5.3-rc3 2019-08-02 08:53:34 -07:00
tools for-linus-20190730 2019-07-30 13:25:14 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore .gitignore: Add compilation database file 2019-07-27 12:18:19 +09:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Char/Misc driver fixes for 5.3-rc2 2019-07-28 10:26:10 -07:00
Makefile Linux 5.3-rc2 2019-07-28 12:47:02 -07:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.