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Yoshihiro Shimoda b2357839c5 usb: renesas_usbhs: add a workaround for a race condition of workqueue
The old commit 6e4b74e469 ("usb: renesas: fix scheduling in atomic
context bug") fixed an atomic issue by using workqueue for the shdmac
dmaengine driver. However, this has a potential race condition issue
between the work pending and usbhsg_ep_free_request() in gadget mode.
When usbhsg_ep_free_request() is called while pending the queue,
since the work_struct will be freed and then the work handler is
called, kernel panic happens on process_one_work().

To fix the issue, if we could call cancel_work_sync() at somewhere
before the free request, it could be easy. However,
the usbhsg_ep_free_request() is called on atomic (e.g. f_ncm driver
calls free request via gether_disconnect()).

For now, almost all users are having "USB-DMAC" and the DMAengine
driver can be used on atomic. So, this patch adds a workaround for
a race condition to call the DMAengine APIs without the workqueue.

This means we still have TODO on shdmac environment (SH7724), but
since it doesn't have SMP, the race condition might not happen.

Fixes: ab330cf388 ("usb: renesas_usbhs: add support for USB-DMAC")
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2019-07-03 11:00:50 +03:00
arch ARM: dts: rockchip: Allow wakeup from rk3288-veyron's dwc2 USB ports 2019-06-18 11:58:28 +03:00
block blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests 2019-06-13 03:05:58 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
Documentation doc: dt-binding: mxs-usb-phy: add compatible for 7ulp 2019-07-03 10:56:16 +03:00
drivers usb: renesas_usbhs: add a workaround for a race condition of workqueue 2019-07-03 11:00:50 +03:00
fs Fix rounding error in gfs2_iomap_page_prepare 2019-06-14 17:27:12 -10:00
include usb:gadget Separated decoding functions from dwc3 driver. 2019-07-03 10:45:58 +03:00
init Char/Misc driver fixes for 5.2-rc4 2019-06-08 12:50:36 -07:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:22:56 -10:00
lib lib/genalloc: introduce chunk owners 2019-06-13 17:34:56 -10:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:28:14 -10:00
net SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
samples SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
scripts scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILE 2019-06-13 17:34:56 -10:00
security Smack: Restore the smackfsdef mount option and add missing prefixes 2019-06-14 14:25:04 -10:00
sound sound fixes for 5.2-rc5 2019-06-14 05:37:06 -10:00
tools mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.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 .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-06-08 12:48:49 -07:00
Makefile Linux 5.2-rc5 2019-06-16 08:49:45 -10:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.