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Mathias Nyman 9e7d7c0347 xhci: make sure TRB is fully written before giving it to the controller 
commit 576667bad3 upstream.

Once the command ring doorbell is rung the xHC controller will parse all
command TRBs on the command ring that have the cycle bit set properly.

If the driver just started writing the next command TRB to the ring when
hardware finished the previous TRB, then HW might fetch an incomplete TRB
as long as its cycle bit set correctly.

A command TRB is 16 bytes (128 bits) long.
Driver writes the command TRB in four 32 bit chunks, with the chunk
containing the cycle bit last. This does however not guarantee that
chunks actually get written in that order.

This was detected in stress testing when canceling URBs with several
connected USB devices.
Two consecutive "Set TR Dequeue pointer" commands got queued right
after each other, and the second one was only partially written when
the controller parsed it, causing the dequeue pointer to be set
to bogus values. This was seen as error messages:

"Mismatch between completed Set TR Deq Ptr command & xHCI internal state"

Solution is to add a write memory barrier before writing the cycle bit.

Cc: <stable@vger.kernel.org>
Tested-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210115161907.2875631-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-27 11:55:17 +01:00
arch x86/setup: don't remove E820_TYPE_RAM for pfn 0 2021-01-27 11:55:14 +01:00
block blk-mq-debugfs: Add decode for BLK_MQ_F_TAG_HCTX_SHARED 2021-01-19 18:27:29 +01:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: xor - Fix divide error in do_xor_speed() 2021-01-27 11:54:52 +01:00
Documentation x86/xen: Add xen_no_vector_callback option to test PCI INTX delivery 2021-01-27 11:55:01 +01:00
drivers xhci: make sure TRB is fully written before giving it to the controller 2021-01-27 11:55:17 +01:00
fs io_uring: fix short read retries for non-reg files 2021-01-27 11:55:15 +01:00
include xen: Fix event channel callback via INTX/GSI 2021-01-27 11:55:00 +01:00
init rcu-tasks: Move RCU-tasks initialization to before early_initcall() 2021-01-19 18:27:28 +01:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel printk: fix kmsg_dump_get_buffer length calulations 2021-01-27 11:55:08 +01:00
lib iov_iter: fix the uaccess area in copy_compat_iovec_from_user 2021-01-27 11:55:09 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: fix numa stats for thp migration 2021-01-27 11:55:14 +01:00
net xsk: Clear pool even for inactive queues 2021-01-27 11:55:10 +01:00
samples samples/bpf: Fix possible hang in xdpsock with multiple threads 2020-12-30 11:53:49 +01:00
scripts Revert "kconfig: remove 'kvmconfig' and 'xenconfig' shorthands" 2021-01-23 16:03:57 +01:00
security dump_common_audit_data(): fix racy accesses to ->d_name 2021-01-19 18:27:29 +01:00
sound ALSA: hda: Balance runtime/system PM if direct-complete is disabled 2021-01-27 11:55:10 +01:00
tools perf evlist: Fix id index for heterogeneous systems 2021-01-27 11:55:11 +01:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: check tlbs_dirty directly 2021-01-12 20:18:22 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile Linux 5.10.10 2021-01-23 16:04:06 +01:00
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.