lkml.org 
[lkml]   [2015]   [Jun]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 0/3] aio: ctx->dead cleanups
    On 06/17, Oleg Nesterov wrote:
    >
    > On 06/17, Al Viro wrote:
    > >
    > > On Wed, Jun 17, 2015 at 01:39:06AM +0100, Al Viro wrote:
    > >
    > > And yes, the leak you've spotted is real, but I would very much prefer
    > > to avoid that goto - something like this instead:
    > >
    > > diff --git a/mm/mremap.c b/mm/mremap.c
    > > index 034e2d3..b36b530 100644
    > > --- a/mm/mremap.c
    > > +++ b/mm/mremap.c
    > > @@ -291,7 +291,10 @@ static unsigned long move_vma(struct vm_area_struct *vma,
    > > if (err < 0) {
    > > move_page_tables(new_vma, new_addr, vma, old_addr,
    > > moved_len, true);
    > > - return err;
    > > + vma = new_vma;
    > > + old_len = new_len;
    > > + old_addr = new_addr;
    > > + new_addr = err;
    >
    > Personally, I'd really prefer to factor out at least this
    > move_page_tables() with six args. Although I agree, "goto previous_if"
    > doesn't look nice too, this needs cleanup.
    >
    > But this is minor. I am already sleeping, most probably I misread
    > this code. But it seems that there is another bug with VM_ACCOUNT.
    >
    > I'll recheck tomorrow and write another email.

    Yes this look wrong. At least we shouldn't set *locked on failure.
    mm->locked_vm += new_len is probably fine, but doesn't look really
    nice because ->locked_vm can underflow in do_munmap() before that.

    I'll send the fixes, but also I'll try to cleanup this code. Not
    sure I will succeed ;)

    Oleg.



    \
     
     \ /
      Last update: 2015-06-18 18:21    [W:3.397 / U:0.284 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site