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Filename Latest commit message Latest commit date
Qian Cai fe688b144c mm/slub: fix stack overruns with SLUB_STATS
[ Upstream commit a68ee0573991e90af2f1785db309206408bad3e5 ]

There is no need to copy SLUB_STATS items from root memcg cache to new
memcg cache copies.  Doing so could result in stack overruns because the
store function only accepts 0 to clear the stat and returns an error for
everything else while the show method would print out the whole stat.

Then, the mismatch of the lengths returns from show and store methods
happens in memcg_propagate_slab_attrs():

	else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
		buf = mbuf;

max_attr_size is only 2 from slab_attr_store(), then, it uses mbuf[64]
in show_stat() later where a bounch of sprintf() would overrun the stack
variable.  Fix it by always allocating a page of buffer to be used in
show_stat() if SLUB_STATS=y which should only be used for debug purpose.

  # echo 1 > /sys/kernel/slab/fs_cache/shrink
  BUG: KASAN: stack-out-of-bounds in number+0x421/0x6e0
  Write of size 1 at addr ffffc900256cfde0 by task kworker/76:0/53251

  Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
  Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
  Call Trace:
    number+0x421/0x6e0
    vsnprintf+0x451/0x8e0
    sprintf+0x9e/0xd0
    show_stat+0x124/0x1d0
    alloc_slowpath_show+0x13/0x20
    __kmem_cache_create+0x47a/0x6b0

  addr ffffc900256cfde0 is located in stack of task kworker/76:0/53251 at offset 0 in frame:
   process_one_work+0x0/0xb90

  this frame has 1 object:
   [32, 72) 'lockdep_map'

  Memory state around the buggy address:
   ffffc900256cfc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   ffffc900256cfd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >ffffc900256cfd80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
                                                         ^
   ffffc900256cfe00: 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 00
   ffffc900256cfe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ==================================================================
  Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: __kmem_cache_create+0x6ac/0x6b0
  Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
  Call Trace:
    __kmem_cache_create+0x6ac/0x6b0

Fixes: 107dab5c92 ("slub: slub-specific propagation changes")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Glauber Costa <glauber@scylladb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200429222356.4322-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-09 09:37:50 +02:00
arch arm64: dts: imx8mn-ddr4-evk: correct ldo1/ldo2 voltage range 2020-06-30 15:37:10 -04:00
block block: update hctx map when use multiple maps 2020-06-30 15:37:06 -04:00
certs
crypto crypto: algboss - don't wait during notifier callback 2020-06-24 17:50:51 +02:00
Documentation dt-bindings: display: mediatek: control dpi pins mode to avoid leakage 2020-06-22 09:30:58 +02:00
drivers usbnet: smsc95xx: Fix use-after-free after removal 2020-07-09 09:37:49 +02:00
fs io_uring: make sure async workqueue is canceled on exit 2020-07-09 09:37:49 +02:00
include net: qed: fix left elements count calculation 2020-06-30 15:36:58 -04:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel sched/debug: Make sd->flags sysctl read-only 2020-07-09 09:37:50 +02:00
lib test_objagg: Fix potential memory leak in error handling 2020-06-30 15:37:04 -04:00
LICENSES
mm mm/slub: fix stack overruns with SLUB_STATS 2020-07-09 09:37:50 +02:00
net xprtrdma: Fix handling of RDMA_ERROR replies 2020-06-30 15:37:12 -04:00
samples bpf, xdp, samples: Fix null pointer dereference in *_user code 2020-06-30 15:36:55 -04:00
scripts recordmcount: support >64k sections 2020-06-30 15:37:05 -04:00
security selinux: fix double free 2020-06-24 17:50:48 +02:00
sound ALSA: hda/realtek: Add mute LED and micmute LED support for HP systems 2020-06-30 15:37:06 -04:00
tools selftests/net: report etf errors correctly 2020-06-30 15:36:58 -04:00
usr
virt KVM: arm64: Save the host's PtrAuth keys in non-preemptible context 2020-06-17 16:40:38 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.50 2020-06-30 16:21:55 -04:00
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.