From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "Zhang, Qiang1" <qiang1.zhang@intel.com>
Cc: "ryabinin.a.a@gmail.com" <ryabinin.a.a@gmail.com>,
"glider@google.com" <glider@google.com>,
"andreyknvl@gmail.com" <andreyknvl@gmail.com>,
"dvyukov@google.com" <dvyukov@google.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>
Subject: Re: [PATCH] kasan: Fix sleeping function called from invalid context in PREEMPT_RT
Date: Fri, 1 Apr 2022 13:15:47 +0200 [thread overview]
Message-ID: <Ykbe46hLAfJ8TsnW@linutronix.de> (raw)
In-Reply-To: <PH0PR11MB58800917A1BF8D1A76BEF84EDAE09@PH0PR11MB5880.namprd11.prod.outlook.com>
On 2022-04-01 10:10:38 [+0000], Zhang, Qiang1 wrote:
> >Could we fix in a way that we don't involve freeing memory from in-IRQ?
> >This could trigger a lockdep splat if the local-lock in SLUB is acquired from in-IRQ context on !PREEMPT_RT.
>
> Hi, I will move qlist_free_all() from IPI context to task context,
> This operation and the next release members
> in the quarantine pool operate similarly
>
> I don't know the phenomenon you described. Can you explain it in detail?
If you mean by phenomenon my second sentence then the kernel option
CONFIG_PROVE_RAW_LOCK_NESTING will trigger on !PREEMPT_RT in a code
sequence like
raw_spin_lock()
spin_lock();
which is wrong on PREEMPT_RT. So we have a warning on both
configurations.
The call chain in your case will probably not lead to a warning since
there is no raw_spinlock_t involved within the IPI call. We worked on
avoiding memory allocation and freeing from in-IRQ context therefore I
would prefer to have something that works for both and not just ifdef
around the RT-case.
> Thanks
> Zqiang
Sebastian
next prev parent reply other threads:[~2022-04-01 11:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 9:10 [PATCH] kasan: Fix sleeping function called from invalid context in PREEMPT_RT Zqiang
2022-04-01 9:27 ` Sebastian Andrzej Siewior
2022-04-01 10:10 ` Zhang, Qiang1
2022-04-01 11:15 ` Sebastian Andrzej Siewior [this message]
2022-04-04 12:12 ` Mike Galbraith
2022-04-01 11:39 ` Dmitry Vyukov
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