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From: Michael Kelley <mikelley@microsoft.com>
To: kimbrownkd <kimbrownkd@gmail.com>, Long Li <longli@microsoft.com>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Dexuan Cui <decui@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 1/2] Drivers: hv: vmbus: Refactor chan->state if statement
Date: Sun, 24 Feb 2019 16:54:03 +0000	[thread overview]
Message-ID: <DM5PR2101MB0918C0F4B89F715C2C643ECBD7790@DM5PR2101MB0918.namprd21.prod.outlook.com> (raw)
In-Reply-To: <1bb109543adc60c1f349e0c6f290591804b4289a.1550806305.git.kimbrownkd@gmail.com>

From: Kimberly Brown <kimbrownkd@gmail.com>  Sent: Thursday, February 21, 2019 7:47 PM
> 
> The chan->state "if statement" was introduced in commit 6712cc9c2211
> ("vmbus: don't return values for uninitalized channels"). That commit
> states that the purpose of the chan->state "if statement" is to prevent
> returning garbage or causing a kernel OOPS when the channel ring buffer
> is not initialized. The changes in this patch provide the same
> protection.
> 
> Refactor the chan->state “if statement” in vmbus_chan_attr_show():
>  - Instead of checking the channel state in the "if statement", check
>    whether the channel ring buffer pointer is NULL. Checking the
>    ring buffer pointer makes this code consistent with
>    hv_ringbuffer_get_debuginfo().
> 
>  - Move the "if statement" to the four "_show" functions that access a
>    channel ring buffer. Only four of the channel-level "_show" functions
>    access a ring buffer. The ring buffer pointer does not need to be
>    checked before calling the other "_show" functions, and moving the
>    ring buffer pointer "if statement" to the "_show" functions that
>    access a ring buffer makes the purpose of the "if statement" clear.
> 
> Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

  reply	other threads:[~2019-02-24 16:54 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-22  2:07 [PATCH] Drivers: hv: vmbus: Add mutex lock to channel show functions Kimberly Brown
2019-01-22  3:46 ` Dexuan Cui
2019-01-22  6:42   ` Kimberly Brown
2019-01-22 18:40     ` Dexuan Cui
2019-01-28 19:58       ` Kimberly Brown
2019-01-29 19:20         ` Dexuan Cui
2019-01-31 15:19           ` Sasha Levin
2019-01-31 16:45             ` Michael Kelley
2019-01-31 17:47               ` Kimberly Brown
2019-02-01 14:13                 ` Sasha Levin
2019-02-01 18:24                 ` Dexuan Cui
2019-02-02 20:07                   ` Kimberly Brown
2019-02-15  1:54                     ` Sasha Levin
2019-02-15  2:27                       ` Kimberly Brown
2019-02-22  3:46 ` [PATCH v2 0/2] Fix a race condition vulnerability in "_show" functions Kimberly Brown
2019-02-22  3:47   ` [PATCH v2 1/2] Drivers: hv: vmbus: Refactor chan->state if statement Kimberly Brown
2019-02-24 16:54     ` Michael Kelley [this message]
2019-02-22  3:47   ` [PATCH v2 2/2] Drivers: hv: vmbus: Add a channel ring buffer mutex lock Kimberly Brown
2019-02-24 16:53     ` Michael Kelley
2019-02-26  6:24       ` Kimberly Brown
2019-03-14 20:04   ` [PATCH v3 0/3] Drivers: hv: vmbus: Fix a race condition in "_show" functions Kimberly Brown
2019-03-14 20:05     ` [PATCH v3 1/3] Drivers: hv: vmbus: Refactor chan->state if statement Kimberly Brown
2019-03-14 20:05     ` [PATCH v3 2/3] Drivers: hv: vmbus: Set ring_info field to 0 and remove memset Kimberly Brown
2019-03-29 16:01       ` Michael Kelley
2019-03-14 20:05     ` [PATCH v3 3/3] Drivers: hv: vmbus: Fix race condition with new ring_buffer_info mutex Kimberly Brown
2019-03-14 22:45       ` Stephen Hemminger
2019-03-17  1:49         ` Kimberly Brown
2019-03-20 20:06           ` Stephen Hemminger
2019-03-21  3:47             ` Kimberly Brown
2019-03-21 16:04               ` Michael Kelley
2019-03-28  4:30                 ` Kimberly Brown
2019-03-28 18:42                   ` Stephen Hemminger
2019-03-29 16:04       ` Michael Kelley
2019-04-10 22:59     ` [PATCH v3 0/3] Drivers: hv: vmbus: Fix a race condition in "_show" functions Sasha Levin

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