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Date:   Thu, 14 Mar 2019 16:04:52 -0400
From:   Kimberly Brown <kimbrownkd@gmail.com>
To:     Michael Kelley <mikelley@microsoft.com>,
        Long Li <longli@microsoft.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>
Cc:     "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 0/3] Drivers: hv: vmbus: Fix a race condition in "_show"
 functions
Message-ID: <cover.1552592620.git.kimbrownkd@gmail.com>
References: <cover.1550806305.git.kimbrownkd@gmail.com>
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This patchset fixes a race condition in the "_show" functions that
access the channel ring buffers.

Changes in v3:
Patch 1: Drivers: hv: vmbus: Refactor chan->state if statement
 - Added the “reviewed-by” line from v2.

Patch 2: Drivers: hv: vmbus: Set ring_info field to 0 and remove memset
 - This patch is new. This change allows the new mutex locks in patch 3
   to be initialized when the channel is initialized.

Patch 3: Drivers: hv: vmbus: Fix race condition with new
         ring_buffer_info mutex
 - Added two ring buffer info mutex locks instead of the single channel
   mutex lock that was proposed in v2.
 - Changed the mutex acquire/release calls as needed for the new ring
   buffer info mutex locks.
 - Updated the commit message.


Changes in v2:
 - In v1, I proposed using “vmbus_connection.channel_mutex” in the
   “_show” functions to prevent the race condition. However, using this
   mutex could result in a deadlock, so a new approach is proposed in
   this patchset.
 - Patch 1 is new and consists of refactoring an if statement.
 - Patch 2 introduces a new mutex lock in the “vmbus_channel” struct,
   which is used to eliminate the race condition.

Kimberly Brown (3):
  Drivers: hv: vmbus: Refactor chan->state if statement
  Drivers: hv: vmbus: Set ring_info field to 0 and remove memset
  Drivers: hv: vmbus: Fix race condition with new ring_buffer_info mutex

 drivers/hv/channel_mgmt.c |  2 +
 drivers/hv/hyperv_vmbus.h |  1 +
 drivers/hv/ring_buffer.c  | 22 ++++++++--
 drivers/hv/vmbus_drv.c    | 89 +++++++++++++++++++++++++++------------
 include/linux/hyperv.h    |  7 ++-
 5 files changed, 88 insertions(+), 33 deletions(-)

-- 
2.17.1