Re: idr_get_new_above() limitation?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 2007-07-02 at 19:19 +0200, Hoang-Nam Nguyen wrote:

> i=3fffffff token=3fffffff t=000000003fffffff
> i=40000000 token=40000000 t=0000000000000000
> Invalid object 0000000000000000. Expected 40000000
> 
> That means token 0x40000000 seems to be the "upper boundary" of idr_find().
> However the behaviour is not consistent in that it was returned by
> idr_get_new_above().

Hi Nam,

Yes this is a bug.  Thanks for the great test module.

The problem is in idr_get_new_above_int() in the loop which
adds new layers to the top of the radix tree.  It is failing
the "layers < (MAX_LEVEL - 1)" test.  It doesn't allocate the
new layer but still calls sub_alloc() which relies on having
the new layer properly constructed.  I believe that it is
allocating the slot which corresponds to id = 0.

I believe this is an off by one error in calculating the
MAX_LEVEL value.  I will do a more careful review and post 
a fix in the next day or so.  I have been in Ottawa for OLS.
I'm flying home tomorrow.

Jim Houston - Concurrent Computer Corp.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux