Re: [PATCH 1/1] driver/tty: Fix a warning in check_tty_count

From: Li, ZhenHua
Date: Wed Jul 16 2014 - 06:38:37 EST


Hi Jiri,
You are right, I tested the latest kernel, did not see this bug.
So I will only submit this patch to Redhat.

Thanks
Zhenhua

On 07/15/2014 05:16 PM, Jiri Slaby wrote:
Hi,

On 07/15/2014 11:08 AM, Li, ZhenHua wrote:
This bug was founded in RHEL 6, kernel version 2.6.32.

But I also checked the file tty_io.c in latest kernel, not all the code
protected by tty_lock(tty).

For example, in function tty_del_file,

if (--tty->count < 0) {
}
and
tty_del_file(filp);
are not surrounded by tty_lock(tty).
Sure, but there is tty_lock_pair instead.

So I think the new lock is necessary.
Nope, sorry, you have to complain to RedHat about this kernel. Unless
you can reproduce this with the vanilla kernel.

thanks,

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