kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-13 07:31:07 +00:00
Code Issues Releases Packages Activity
No description
712,194 commits 117 branches 5,827 tags 6.3 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Lukas Wunner ad25cf42f4 can: hi311x: Acquire SPI lock on ->do_get_berr_counter 
commit 5cec9425b4 upstream.

hi3110_get_berr_counter() may run concurrently to the rest of the driver
but neglects to acquire the lock protecting access to the SPI device.
As a result, it and the rest of the driver may clobber each other's tx
and rx buffers.

We became aware of this issue because transmission of packets with
"cangen -g 0 -i -x" frequently hung.  It turns out that agetty executes
->do_get_berr_counter every few seconds via the following call stack:

    CPU: 2 PID: 1605 Comm: agetty
    [<7f3f7500>] (hi3110_get_berr_counter [hi311x])
    [<7f130204>] (can_fill_info [can_dev])
    [<80693bc0>] (rtnl_fill_ifinfo)
    [<806949ec>] (rtnl_dump_ifinfo)
    [<806b4834>] (netlink_dump)
    [<806b4bc8>] (netlink_recvmsg)
    [<8065f180>] (sock_recvmsg)
    [<80660f90>] (___sys_recvmsg)
    [<80661e7c>] (__sys_recvmsg)
    [<80661ec0>] (SyS_recvmsg)
    [<80108b20>] (ret_fast_syscall+0x0/0x1c)

agetty listens to netlink messages in order to update the login prompt
when IP addresses change (if /etc/issue contains \4 or \6 escape codes):
https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=e36deb6424e8

It's a useful feature, though it seems questionable that it causes CAN
bit error statistics to be queried.

Be that as it may, if hi3110_get_berr_counter() is invoked while a frame
is sent by hi3110_hw_tx(), bogus SPI transfers like the following may
occur:

    => 12 00             (hi3110_get_berr_counter() wanted to transmit
                          EC 00 to query the transmit error counter,
                          but the first byte was overwritten by
                          hi3110_hw_tx_frame())

    => EA 00 3E 80 01 FB (hi3110_hw_tx_frame() wanted to transmit a
                          frame, but the first byte was overwritten by
                          hi3110_get_berr_counter() because it wanted
                          to query the receive error counter)

This sequence hangs the transmission because the driver believes it has
sent a frame and waits for the interrupt signaling completion, but in
reality the chip has never sent away the frame since the commands it
received were malformed.

Fix by acquiring the SPI lock in hi3110_get_berr_counter().

I've scrutinized the entire driver for further unlocked SPI accesses but
found no others.

Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Akshay Bhat <akshay.bhat@timesys.com>
Cc: Casey Fitzpatrick <casey.fitzpatrick@timesys.com>
Cc: Stef Walter <stefw@redhat.com>
Cc: Karel Zak <kzak@redhat.com>
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Akshay Bhat <akshay.bhat@timesys.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-05-16 10:10:28 +02:00
arch arm64: Add work around for Arm Cortex-A55 Erratum 1024718 2018-05-16 10:10:25 +02:00
block bfq-iosched: ensure to clear bic/bfqq pointers when preparing request 2018-05-01 12:58:19 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: af_alg - fix possible uninit-value in alg_bind() 2018-05-16 10:10:23 +02:00
Documentation arm64: Add work around for Arm Cortex-A55 Erratum 1024718 2018-05-16 10:10:25 +02:00
drivers
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs ceph: fix rsize/wsize capping in ceph_direct_read_write() 2018-05-16 10:10:27 +02:00
include mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-24 09:36:23 +02:00
kernel tracing: Fix regex_match_front() to not over compare the test string 2018-05-16 10:10:27 +02:00
lib errseq: Always report a writeback error once 2018-05-09 09:51:54 +02:00
mm mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
net rfkill: gpio: fix memory leak in probe error path 2018-05-16 10:10:26 +02:00
samples samples/bpf: Partially fixes the bpf.o build 2018-04-26 11:02:12 +02:00
scripts kconfig: Fix expr_free() E_NOT leak 2018-04-26 11:02:08 +02:00
security commoncap: Handle memory allocation failure. 2018-04-29 11:33:16 +02:00
sound ALSA: aloop: Add missing cable lock to ctl API callbacks 2018-05-09 09:51:50 +02:00
tools test_firmware: fix setting old custom fw path back on exit, second try 2018-05-09 09:51:54 +02:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt arm/arm64: KVM: Add PSCI version selection API 2018-05-01 12:58:27 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.40 2018-05-09 09:51:56 +02:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

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.