linux-kernel - Re: [patch V2 07/50] posix-cpu-timers: Split up posix_cpu_timer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240417110803.GA27840@redhat.com>
Date: Wed, 17 Apr 2024 13:08:03 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Anna-Maria Behnsen <anna-maria@...utronix.de>
Cc: Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <frederic@...nel.org>,
	John Stultz <jstultz@...gle.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, Stephen Boyd <sboyd@...nel.org>,
	Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [patch V2 07/50] posix-cpu-timers: Split up posix_cpu_timer_get()

On 04/17, Anna-Maria Behnsen wrote:
>
> Oleg Nesterov <oleg@...hat.com> writes:
>
> > On 04/11, Thomas Gleixner wrote:
> >>
> >> In preparation for addressing issues in the timer_get() and timer_set()
> >> functions of posix CPU timers.
> >
> > Cough... I must have missed something, but posix_cpu_timer_get()
> > doesn't look right with or without this trivial patch.
> >
> > It doesn't initialize itp->it_value if cpu_timer_getexpires() == 0,
> > this means that sys_timer_gettime() will copy the uninitialized
> > cur_setting->it_value on the stack to userspace?
>
> The initialization of itp is already done by the callsites.
> do_timer_settime() in posix-timers.c as well as do_cpu_nanosleep() in
> posix-cpu-timers.c execute a memset before calling
> posix_cpu_timer_get().

Indeed. Somehow I missed this memset(). Even if I tried to read the
simple do_timer_gettime/posix_cpu_timer_get functions several times ;)

Thanks for correcting me!

Oleg.