From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Petr Mladek <pmladek@suse.com>
Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Seth Forshee <sforshee@kernel.org>,
Peter Zijlstra <peterz@infradead.org>, Song Liu <song@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Miroslav Benes <mbenes@suse.cz>, Jiri Kosina <jikos@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH 0.5/3] livepatch: Convert stack entries array to percpu
Date: Tue, 14 Mar 2023 17:26:08 -0700 [thread overview]
Message-ID: <20230315002608.sulru3taycwrmvki@treble> (raw)
In-Reply-To: <ZBBRbfAL5+ZI77XN@alley>
On Tue, Mar 14, 2023 at 11:50:21AM +0100, Petr Mladek wrote:
> > static int klp_check_stack(struct task_struct *task, const char **oldname)
> > {
> > - static unsigned long entries[MAX_STACK_ENTRIES];
> > + unsigned long *entries = this_cpu_ptr(klp_stack_entries);
> > struct klp_object *obj;
> > struct klp_func *func;
> > int ret, nr_entries;
> >
> > - ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries));
> > + /* Protect 'klp_stack_entries' */
> > + lockdep_assert_preemption_disabled();
>
> I think about adding:
>
> /*
> * Stay on the safe side even when cond_resched() is called from
> * an IRQ context by mistake.
> */
> if (!in_task())
> return -EINVAL;
>
> Or is this prevented another way, please?
An IRQ handler trying to schedule would be a pretty major bug, no?
I think there are already several different checks for that. For
example, the __might_resched() call in cond_resched().
--
Josh
next prev parent reply other threads:[~2023-03-15 0:26 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 16:49 [PATCH v3 0/3] livepatch,sched: Add livepatch task switching to cond_resched() Josh Poimboeuf
2023-02-24 16:49 ` [PATCH v3 1/3] livepatch: Skip task_call_func() for current task Josh Poimboeuf
2023-02-24 16:50 ` [PATCH v3 2/3] livepatch,sched: Add livepatch task switching to cond_resched() Josh Poimboeuf
2023-02-27 15:55 ` Petr Mladek
2023-02-28 16:56 ` Josh Poimboeuf
2023-03-03 14:00 ` Petr Mladek
2023-03-13 23:33 ` [PATCH 0.5/3] livepatch: Convert stack entries array to percpu Josh Poimboeuf
2023-03-14 10:50 ` Petr Mladek
2023-03-15 0:26 ` Josh Poimboeuf [this message]
2023-02-24 16:50 ` [PATCH v3 3/3] vhost: Fix livepatch timeouts in vhost_worker() Josh Poimboeuf
2023-02-28 16:39 ` [PATCH v3 0/3] livepatch,sched: Add livepatch task switching to cond_resched() Seth Forshee
2023-03-30 16:11 ` Miroslav Benes
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