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Netanel Belgazal 661d2b0cce net: ena: fix race condition between submit and completion admin command
Bug:
"Completion context is occupied" error printout will be noticed in
dmesg.
This error will cause the admin command to fail, which will lead to
an ena_probe() failure or a watchdog reset (depends on which admin
command failed).

Root cause:
__ena_com_submit_admin_cmd() is the function that submits new entries to
the admin queue.
The function have a check that makes sure the queue is not full and the
function does not override any outstanding command.
It uses head and tail indexes for this check.
The head is increased by ena_com_handle_admin_completion() which runs
from interrupt context, and the tail index is increased by the submit
function (the function is running under ->q_lock, so there is no risk
of multithread increment).
Each command is associated with a completion context. This context
allocated before call to __ena_com_submit_admin_cmd() and freed by
ena_com_wait_and_process_admin_cq_interrupts(), right after the command
was completed.

This can lead to a state where the head was increased, the check passed,
but the completion context is still in use.

Solution:
Use the atomic variable ->outstanding_cmds instead of using the head and
the tail indexes.
This variable is safe for use since it is bumped in get_comp_ctx() in
__ena_com_submit_admin_cmd() and is freed by comp_ctxt_release()

Fixes: 1738cd3ed3 ("Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-11 16:36:46 -04:00
arch bpf, arm64: use separate register for state in stxr 2017-06-07 15:27:20 -04:00
block block: Avoid that blk_exit_rl() triggers a use-after-free 2017-06-01 13:07:55 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto: skcipher - Add missing API setkey checks 2017-05-18 13:04:05 +08:00
Documentation net: fix up hash documentation 2017-06-07 13:00:41 -04:00
drivers net: ena: fix race condition between submit and completion admin command 2017-06-11 16:36:46 -04:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs fs/ufs: Set UFS default maximum bytes per file 2017-06-04 16:33:54 -07:00
include ethtool.h: remind to update 802.3ad when adding new speeds 2017-06-08 16:05:41 -04:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Merge branch 'for-4.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-06-05 15:37:03 -07:00
lib test_bpf: Add a couple of tests for BPF_JSGE. 2017-05-25 14:37:56 -04:00
mm mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
net net: tipc: Fix a sleep-in-atomic bug in tipc_msg_reverse 2017-06-10 18:20:38 -04:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
security Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
sound sound fixes for 4.12-rc4 2017-06-02 09:40:47 -07:00
tools bpf, tests: fix endianness selection 2017-06-08 16:17:29 -04:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-06 14:30:17 -07:00
Makefile Linux 4.12-rc4 2017-06-04 16:47:43 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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.