Re: [PATCH] secure unlock_task_sighand() call

2013-12-23 Thread Linus Torvalds
On Mon, Dec 23, 2013 at 4:29 AM, naveen yadav wrote: > > We are facing OOPS during core dump on kernel 3.8.x on ARM target. > > So we were doing core review and found this. We do not know whether > its big issue but thought to share this considering the problem Can you please post the oops, just

Re: [PATCH] secure unlock_task_sighand() call

2013-12-23 Thread Oleg Nesterov
On 12/23, naveen yadav wrote: > > Happy Christmas !!! Thanks, the same to you ;) > We are facing OOPS during core dump on kernel 3.8.x on ARM target. Do you have any traces? Any additional info? Can you try the fresh kernels? Not that I can recall any change in this area which could help, but

Re: [PATCH] secure unlock_task_sighand() call

2013-12-23 Thread naveen yadav
Happy Christmas !!! Thanks Oleg and Linus for your reply. We are facing OOPS during core dump on kernel 3.8.x on ARM target. So we were doing core review and found this. We do not know whether its big issue but thought to share this considering the problem Also I think in zap_process() ther

Re: [PATCH] secure unlock_task_sighand() call

2013-12-22 Thread Oleg Nesterov
Naveen, sorry for the terse and neglectful reply yesterday. Actually, when I re-read the Linus's email, I think he already explained everything, so let me repeat: On 12/21, Linus Torvalds wrote: > > Did you actually *see* the problem, or was this just from looking at the code? Yes. Because this

Re: [PATCH] secure unlock_task_sighand() call

2013-12-21 Thread Oleg Nesterov
On 12/21, Linus Torvalds wrote: > > We have coredump serialization in exit_mm() that I think *should* make > this all ok - if we still see p->mm matching our mm, Yes. And the comment says: lock_task_sighand(p) must be used. Since p->mm != NULL and we hold ->mmap_sem it can

Re: [PATCH] secure unlock_task_sighand() call

2013-12-21 Thread Linus Torvalds
Did you actually *see* the problem, or was this just from looking at the code? I don't hate the patch, and it might be the right thing to do in any case (just to avoid depending on subtle things), but this really *is* subtle, and I'm adding Oleg to the participants since it is his code (going back