Re: [syzbot] BUG: sleeping function called from invalid context in _copy_to_iter

[Shoaib Rao]

On 8/10/21 11:02 AM, Eric Dumazet wrote:
> On Tue, Aug 10, 2021 at 7:50 PM Shoaib Rao <rao.shoaib@xxxxxxxxxx> wrote:
> > On 8/10/21 2:19 AM, Eric Dumazet wrote:
> > > On 8/9/21 10:31 PM, Shoaib Rao wrote:
> > > > On 8/9/21 1:09 PM, Eric Dumazet wrote:
> > > > > I am guessing that even your test would trigger the warning,
> > > > > if you make sure to include CONFIG_DEBUG_ATOMIC_SLEEP=y in your kernel build.
> > > > Eric,
> > > >
> > > > Thanks for the pointer, have you ever over looked at something when coding?
> > > I _think_ I was trying to help, not shaming you in any way.
> > How did the previous email help? I did not get any reply when I asked
> > what could be the cause.
> Which previous email ? Are you expecting immediate answers to your emails ?
> I am not working for Oracle.
>
> > > My question about spinlock/mutex was not sarcastic, you authored
> > > 6 official linux patches, there is no evidence for linux kernel expertise.
> > That is no measure of someones understanding. There are other OS's as
> > well. I have worked on Solaris and other *unix* OS's for over 20+ years.
> > This was an oversight on my part and I apologize, but instead of
> > questioning my expertise it would have been helpful to say what might
> > have caused it.
>
> I sent two emails with _useful_ _information_.
>
> If you felt you were attacked, I suggest you take a deep breath,
> and read my emails without trying to change their intention and meaning.
>
> If you think my emails were not useful, just ignore them, this is fine by me.

Hi Eric,

I went back and looked at the two emails. You are correct.

> Are you aware of the difference between a mutex and a spinlock ?
>
> When copying data from/to user, you can not hold a spinlock.
The second line is useful but the first one was not necessary.

Shoaib