lkml.org 
[lkml]   [2008]   [Feb]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch] NULL pointer check for vma->vm_mm
    On Fri, 1 Feb 2008 16:39:07 +0900 "Kenichi Okuyama" <kenichi.okuyama@gmail.com> wrote:

    > Dear all,
    >
    > I was looking at the ./mm/rmap.c .. I found that, in function
    > "page_referenced_one()",
    > struct mm_struct *mm = vma->vm_mm;
    > was being refererred without NULL check.
    >
    > Though I do agree that this works for most of the cases, I thought it
    > is better to add
    > BUG_ON() for case of mm being NULL.
    >
    > attached is the patch for this

    If we dereference NULL then the kernel will display basically the same
    information as would a BUG, and it takes the same action. So adding a
    BUG_ON here really doesn't gain us anything.

    Also, I think vma->vm_mm == 0 is not a valid state, so this just shouldn't
    happen - the code is OK to assume that a particular invariant is being
    honoured.



    \
     
     \ /
      Last update: 2008-02-01 08:59    [W:0.030 / U:0.152 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site