Re: kmemleak: unreferenced object in copy_thread

Wouter M. Koolen
2011-11-30T20:07:10Z

Add i915 maintainer Keith Packard to CC.

On 11/30/2011 08:02 PM, Wouter M. Koolen wrote:
>
> On 11/30/2011 11:54 AM, Catalin Marinas wrote:
>> I can't yet tell whether it's a false positive or not. Did the X
>> server die? Is the process with pid 1415 still around? The leaked
>> object looks like the thread stack (8K) and it should have been
>> removed when the corresponding process was killed.
> Hi Catalin,
>
> Just got lucky and hit it again. This time it occurred without
> killing. Here's the splat:
>
> unreferenced object 0xffff880003eda000 (size 8192):
> comm "Xorg", pid 1117, jiffies 4295143832 (age 34745.832s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 0f 00 00 00 0f 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff813feeb1>] kmemleak_alloc+0x21/0x50
> [<ffffffff8111086b>] kmem_cache_alloc_trace+0xdb/0x1d0
> [<ffffffff81001fbe>] copy_thread+0x1be/0x260
> [<ffffffff81044953>] copy_process+0xee3/0x1520
> [<ffffffff810450d6>] do_fork+0x116/0x350
> [<ffffffff8100a7d3>] sys_clone+0x23/0x30
> [<ffffffff8141c173>] stub_clone+0x13/0x20
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> The process 1117 is still alive. It is
>
> root 1117 2.1 1.3 147484 28152 tty7 Ss+ 09:55 13:02
> /usr/bin/X :0 vt7 -br -nolisten tcp -auth /var/run/xauth/A:0-Tdu4bb
>
>
> Actually, there now are several splats of a second kind, relating to
> i915 gem buffers (attached). This type of splat has been reported
> before in
> https://lkml.org/lkml/2011/10/4/15
> although that thread seems to be a dead end. Maybe these warnings have
> a common source?
>
> What would be a good next step?
>
> With kind regards,
>
> Wouter Koolen