lkml.org 
[lkml]   [2013]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] print_worker_info: Handle pointer with more care
Am 16.08.2013 18:12, schrieb Tejun Heo:
> On Fri, Aug 16, 2013 at 05:56:46PM +0200, Richard Weinberger wrote:
>> The function has a nice comment:
>> /*
>> * This function is called without any synchronization and @task
>> * could be in any state. Be careful with dereferences.
>> */
>>
>> But a few lines later it blindly dereferences a few pointers.
>> E.g. It can happen that the worker function is already done,
>> then worker->current_pwq is NULL.
> ...
>> probe_kernel_read(&fn, &worker->current_func, sizeof(fn));
>> probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq));
>> + if (!pwq)
>> + goto print;
>> +
>> probe_kernel_read(&wq, &pwq->wq, sizeof(wq));
>> + if (!wq)
>> + goto print;
>> +
>
> But none of the above are dereferences. &ptr->field is offset
> calculation, not a dereference.

On UML I hit the case that pwq is NULL.
Then we oops at &pwq->wq...

Thanks,
//richard



\
 
 \ /
  Last update: 2013-08-16 18:41    [W:0.055 / U:0.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site