From: Thomas Gleixner <tglx@linutronix.de>
To: Ondrej Mosnacek <omosnace@redhat.com>
Cc: linux-audit@redhat.com, Paul Moore <paul@paul-moore.com>,
Richard Guy Briggs <rgb@redhat.com>,
Steve Grubb <sgrubb@redhat.com>,
Miroslav Lichvar <mlichvar@redhat.com>,
John Stultz <john.stultz@linaro.org>,
Stephen Boyd <sboyd@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH ghak10 v6 1/2] timekeeping: Audit clock adjustments
Date: Thu, 28 Mar 2019 00:37:12 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1903280020390.1789@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190307123254.348-2-omosnace@redhat.com>
On Thu, 7 Mar 2019, Ondrej Mosnacek wrote:
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2512,6 +2512,14 @@ void __audit_fanotify(unsigned int response)
> AUDIT_FANOTIFY, "resp=%u", response);
> }
>
> +/* We need to allocate with GFP_ATOMIC here, since these two functions will be
> + * called while holding the timekeeping lock: */
Audit is no justification for doing ATOMIC allocations just because it's
convenient in the middle of code which blocks every concurrent reader.
Please find a place outside of the timekeeper lock to do that audit
logging. Either that or allocate your buffer upfront in a preemptible
section and commit after the critical section.
/*
* Aside of that please use proper multiline comment style and not this
* horrible other one.
*/
> +void __audit_tk_injoffset(struct timespec64 offset)
> +{
> + audit_log(audit_context(), GFP_ATOMIC, AUDIT_TIME_INJOFFSET,
> + "sec=%lli nsec=%li", (long long)offset.tv_sec, offset.tv_nsec);
> +}
> +
> @@ -1250,6 +1251,9 @@ out:
> /* signal hrtimers about time change */
> clock_was_set();
>
> + if (!ret)
> + audit_tk_injoffset(ts_delta);
This one does not need GFP_ATOMIC at all.
> +
> return ret;
> }
> EXPORT_SYMBOL(do_settimeofday64);
> @@ -2322,6 +2326,8 @@ int do_adjtimex(struct timex *txc)
> ret = timekeeping_inject_offset(&delta);
> if (ret)
> return ret;
> +
> + audit_tk_injoffset(delta);
> }
>
> ktime_get_real_ts64(&ts);
This can be done at the end of do_adjtimex() quite nicely in preemptible
context.
Thanks,
tglx
next prev parent reply other threads:[~2019-03-27 23:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-07 12:32 [RFC PATCH ghak10 v6 0/2] audit: Log changes that can affect the system clock Ondrej Mosnacek
2019-03-07 12:32 ` [RFC PATCH ghak10 v6 1/2] timekeeping: Audit clock adjustments Ondrej Mosnacek
2019-03-08 17:57 ` Steve Grubb
2019-03-27 23:26 ` John Stultz
2019-04-01 9:15 ` Ondrej Mosnacek
2019-03-27 23:37 ` Thomas Gleixner [this message]
2019-03-28 0:10 ` Thomas Gleixner
2019-03-28 0:24 ` Thomas Gleixner
2019-04-01 9:16 ` Ondrej Mosnacek
2019-04-02 9:06 ` Thomas Gleixner
2019-03-07 12:32 ` [RFC PATCH ghak10 v6 2/2] ntp: Audit NTP parameters adjustment Ondrej Mosnacek
2019-03-08 17:59 ` Steve Grubb
2019-03-27 23:29 ` John Stultz
2019-03-28 0:02 ` Thomas Gleixner
2019-04-01 9:13 ` Ondrej Mosnacek
2019-04-02 9:03 ` Thomas Gleixner
2019-04-02 15:02 ` Ondrej Mosnacek
2019-03-08 20:25 ` [RFC PATCH ghak10 v6 0/2] audit: Log changes that can affect the system clock Richard Guy Briggs
2019-03-11 11:48 ` Ondrej Mosnacek
2019-03-25 14:50 ` Paul Moore
2019-03-27 23:00 ` Paul Moore
2019-04-01 9:21 ` Ondrej Mosnacek
2019-03-27 23:36 ` John Stultz
2019-03-28 0:03 ` Thomas Gleixner
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