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>
next prev parent reply other threads:[~2019-02-24 16:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190122020759.GA4054@ubu-Virtual-Machine>
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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