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Robert Richter ce8b9b8032 EDAC/mc: Fix use-after-free and memleaks during device removal 
commit 216aa145aa upstream.

A test kernel with the options DEBUG_TEST_DRIVER_REMOVE, KASAN and
DEBUG_KMEMLEAK set, revealed several issues when removing an mci device:

1) Use-after-free:

On 27.11.19 17:07:33, John Garry wrote:
> [   22.104498] BUG: KASAN: use-after-free in
> edac_remove_sysfs_mci_device+0x148/0x180

The use-after-free is caused by the mci_for_each_dimm() macro called in
edac_remove_sysfs_mci_device(). The iterator was introduced with

  c498afaf7d ("EDAC: Introduce an mci_for_each_dimm() iterator").

The iterator loop calls device_unregister(&dimm->dev), which removes
the sysfs entry of the device, but also frees the dimm struct in
dimm_attr_release(). When incrementing the loop in mci_for_each_dimm(),
the dimm struct is accessed again, after having been freed already.

The fix is to free all the mci device's subsequent dimm and csrow
objects at a later point, in _edac_mc_free(), when the mci device itself
is being freed.

This keeps the data structures intact and the mci device can be
fully used until its removal. The change allows the safe usage of
mci_for_each_dimm() to release dimm devices from sysfs.

2) Memory leaks:

Following memory leaks have been detected:

 # grep edac /sys/kernel/debug/kmemleak | sort | uniq -c
       1     [<000000003c0f58f9>] edac_mc_alloc+0x3bc/0x9d0      # mci->csrows
      16     [<00000000bb932dc0>] edac_mc_alloc+0x49c/0x9d0      # csr->channels
      16     [<00000000e2734dba>] edac_mc_alloc+0x518/0x9d0      # csr->channels[chn]
       1     [<00000000eb040168>] edac_mc_alloc+0x5c8/0x9d0      # mci->dimms
      34     [<00000000ef737c29>] ghes_edac_register+0x1c8/0x3f8 # see edac_mc_alloc()

All leaks are from memory allocated by edac_mc_alloc().

Note: The test above shows that edac_mc_alloc() was called here from
ghes_edac_register(), thus both functions show up in the stack trace
but the module causing the leaks is edac_mc. The comments with the data
structures involved were made manually by analyzing the objdump.

The data structures listed above and created by edac_mc_alloc() are
not properly removed during device removal, which is done in
edac_mc_free().

There are two paths implemented to remove the device depending on device
registration, _edac_mc_free() is called if the device is not registered
and edac_unregister_sysfs() otherwise.

The implemenations differ. For the sysfs case, the mci device removal
lacks the removal of subsequent data structures (csrows, channels,
dimms). This causes the memory leaks (see mci_attr_release()).

 [ bp: Massage commit message. ]

Fixes: c498afaf7d ("EDAC: Introduce an mci_for_each_dimm() iterator")
Fixes: faa2ad09c0 ("edac_mc: edac_mc_free() cannot assume mem_ctl_info is registered in sysfs.")
Fixes: 7a623c0390 ("edac: rewrite the sysfs code to use struct device")
Reported-by: John Garry <john.garry@huawei.com>
Signed-off-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: John Garry <john.garry@huawei.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200212120340.4764-3-rrichter@marvell.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2020-02-19 19:53:03 +01:00
Documentation dt-bindings: iio: adc: ad7606: Fix wrong maxItems value 2020-02-14 16:34:19 -05:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch arm64: ssbs: Fix context-switch when SSBS is present on all CPUs 2020-02-19 19:53:02 +01:00
block block: fix memleak of bio integrity data 2020-01-26 10:01:09 +01:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: testmgr - don't try to decrypt uninitialized buffers 2020-02-14 16:34:18 -05:00
drivers EDAC/mc: Fix use-after-free and memleaks during device removal 2020-02-19 19:53:03 +01:00
fs cifs: make sure we do not overflow the max EA buffer size 2020-02-19 19:53:03 +01:00
include ACPICA: Introduce acpi_any_gpe_status_set() 2020-02-19 19:52:57 +01:00
init Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-02-01 09:34:53 +00:00
ipc ipc/msg.c: consolidate all xxxctl_down() functions 2020-02-11 04:35:07 -08:00
kernel ACPI: PM: s2idle: Avoid possible race related to the EC GPE 2020-02-19 19:52:56 +01:00
lib lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() 2020-02-11 04:35:14 -08:00
mm mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:35:42 -08:00
net xprtrdma: Fix DMA scatter-gather list mapping imbalance 2020-02-19 19:53:02 +01:00
samples samples/bpf: Xdp_redirect_cpu fix missing tracepoint attach 2020-02-11 04:35:29 -08:00
scripts scripts/find-unused-docs: Fix massive false positives 2020-02-11 04:35:23 -08:00
security selinux: fall back to ref-walk if audit is required 2020-02-14 16:34:20 -05:00
sound ALSA: usb-audio: Add clock validity quirk for Denon MC7000/MCX8000 2020-02-19 19:52:57 +01:00
tools tools/power/acpi: fix compilation error 2020-02-14 16:34:15 -05:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-09 10:20:00 +01:00
virt KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer 2020-02-14 16:34:18 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
…
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: correct entries for ISDN/mISDN section 2020-02-11 04:35:06 -08:00
Makefile Linux 5.4.20 2020-02-14 16:34:20 -05:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.