Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Hugh Dickins
On Wed, 26 Mar 2014, Sasha Levin wrote: > On 03/26/2014 03:55 PM, Andrew Morton wrote: > > On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin > > wrote: > > > Out of curiosity, is there a reason not to do bad flag checks when > > > actually > > > setting flag? Obviously it'll be slower but it'll be

Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Sasha Levin
On 03/27/2014 11:21 AM, Hugh Dickins wrote: I've thought about this some, and slept on it, but don't yet see how it comes about. I'll have to come back to it later. Was it a one-off, or do you find it fairly easy to reproduce? If the latter, it would be interesting to know if it comes from

Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Hugh Dickins
On Wed, 26 Mar 2014, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following. > > Out of curiosity, is there a reason not to do bad flag checks when actually > setting flag? Obviously it'll be slower

Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Hugh Dickins
On Wed, 26 Mar 2014, Sasha Levin wrote: Hi all, While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following. Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but it'll

Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Sasha Levin
On 03/27/2014 11:21 AM, Hugh Dickins wrote: I've thought about this some, and slept on it, but don't yet see how it comes about. I'll have to come back to it later. Was it a one-off, or do you find it fairly easy to reproduce? If the latter, it would be interesting to know if it comes from

Re: mm: BUG: Bad page state in process ksmd

2014-03-27 Thread Hugh Dickins
On Wed, 26 Mar 2014, Sasha Levin wrote: On 03/26/2014 03:55 PM, Andrew Morton wrote: On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin sasha.le...@oracle.com wrote: Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but

Re: mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Sasha Levin
On 03/26/2014 03:55 PM, Andrew Morton wrote: On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin wrote: Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but it'll be easier catching these issues. Tricky. Each code site must

Re: mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Andrew Morton
On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following. (cc Hugh) > Out of curiosity, is there a reason not to do bad flag checks when actually > setting flag?

mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Sasha Levin
Hi all, While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following. Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but it'll be easier catching these issues. [

mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Sasha Levin
Hi all, While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following. Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but it'll be easier catching these issues. [

Re: mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Andrew Morton
On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin sasha.le...@oracle.com wrote: Hi all, While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following. (cc Hugh) Out of curiosity, is there a reason not to do bad flag checks when actually

Re: mm: BUG: Bad page state in process ksmd

2014-03-26 Thread Sasha Levin
On 03/26/2014 03:55 PM, Andrew Morton wrote: On Wed, 26 Mar 2014 11:13:27 -0400 Sasha Levin sasha.le...@oracle.com wrote: Out of curiosity, is there a reason not to do bad flag checks when actually setting flag? Obviously it'll be slower but it'll be easier catching these issues. Tricky.