From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Uladzislau Rezki <urezki@gmail.com>,
Florian Westphal <fw@strlen.de>, Michal Hocko <mhocko@suse.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org,
Martin Zaharinov <micron10@gmail.com>
Subject: Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC
Date: Mon, 26 Sep 2022 17:28:43 +0200 [thread overview]
Message-ID: <YzHFK01dNy5dKJDO@linutronix.de> (raw)
In-Reply-To: <76d0cb2b-a963-b867-4399-3e3c4828ecc4@suse.cz>
On 2022-09-26 17:03:48 [+0200], Vlastimil Babka wrote:
> > Doing the "p = kmalloc(sizeof(*p), GFP_ATOMIC);" from an atomic context
> > is also a problem nowadays. Such code should be fixed across the kernel
> > because of PREEMPT_RT support.
You should make sure that the context in question is atomic on
PREEMPT_RT before fixing it. My guess here is that it is average the
softirq (NAPI) callback which is fine.
> But the "atomic context" here is different, no? Calling kmalloc() from IRQ
> handlers AFAIK is ok as IRQ handlers are threaded on PREEMPT_RT. Calling it
> inside an local_irq_disable() would be a problem on the other hand. But then
> under e.g. spin_lock_irqsave() could be ok as those don't really disable
> irqs on RT.
correct.
Sebastian
next prev parent reply other threads:[~2022-09-26 16:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 10:38 [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC Florian Westphal
2022-09-23 13:29 ` Michal Hocko
2022-09-23 13:35 ` Florian Westphal
2022-09-23 14:43 ` Uladzislau Rezki
2022-09-23 14:54 ` Florian Westphal
2022-09-23 15:10 ` Uladzislau Rezki
2022-09-26 15:03 ` Vlastimil Babka
2022-09-26 15:28 ` Sebastian Andrzej Siewior [this message]
2022-09-26 7:49 ` Michal Hocko
2022-09-26 7:56 ` Florian Westphal
2022-09-26 8:57 ` Michal Hocko
2022-09-26 9:30 ` Michal Hocko
2022-09-26 10:08 ` Florian Westphal
2022-09-26 12:02 ` Michal Hocko
2022-09-26 13:08 ` Florian Westphal
2022-09-26 13:38 ` Florian Westphal
2022-09-26 14:05 ` Michal Hocko
2022-09-26 14:20 ` Florian Westphal
2022-09-26 14:32 ` Michal Hocko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YzHFK01dNy5dKJDO@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=akpm@linux-foundation.org \
--cc=fw@strlen.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=micron10@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=urezki@gmail.com \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).