Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return value

From	Andrew Morton <akpm@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return value
Date	2016-08-31 22:30 +0200
Message-ID	<sckiZ-74j-27@gated-at.bofh.it> (permalink)
References	<scfjk-40K-55@gated-at.bofh.it> <scfW2-4eb-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, 31 Aug 2016 10:44:01 -0500 Reza Arbab <arbab@linux.vnet.ibm.com> wrote:

> Attempting to online memory which is already online will cause this:
> 
> 1. store_mem_state() called with buf="online"
> 2. device_online() returns 1 because device is already online
> 3. store_mem_state() returns 1
> 4. calling code interprets this as 1-byte buffer read
> 5. store_mem_state() called again with buf="nline"
> 6. store_mem_state() returns -EINVAL
> 
> Example:
> 
> $ cat /sys/devices/system/memory/memory0/state
> online
> $ echo online > /sys/devices/system/memory/memory0/state
> -bash: echo: write error: Invalid argument
> 
> Fix the return value of store_mem_state() so this doesn't happen.

So..  what *does* happen after the patch?  Is some sort of failure still
reported?  Or am I correct in believing that the operation will appear
to have succeeded?  If so, is that desirable?

Thread

Re: [PATCH v2] memory-hotplug: fix store_mem_state() return value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-31 14:30 +0200
  Re: [PATCH v2] memory-hotplug: fix store_mem_state() return value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-08-31 16:40 +0200
    Re: [PATCH v2] memory-hotplug: fix store_mem_state() return value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-31 17:10 +0200
      [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-08-31 17:50 +0200
        Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value Andrew Morton <akpm@linux-foundation.org> - 2016-08-31 22:30 +0200
          Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value David Rientjes <rientjes@google.com> - 2016-08-31 23:10 +0200
            Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-01 01:40 +0200
              Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value David Rientjes <rientjes@google.com> - 2016-09-01 02:10 +0200
                Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-01 02:20 +0200
                Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value David Rientjes <rientjes@google.com> - 2016-09-01 02:30 +0200
                Re: [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return  value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-09-01 04:00 +0200
  [RESEND PATCH v2] memory-hotplug: fix store_mem_state() return value Reza Arbab <arbab@linux.vnet.ibm.com> - 2016-08-31 16:40 +0200

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