From: Vlastimil Babka <vbabka@suse.cz>
To: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>, lgoncalv@redhat.com
Cc: akpm@linux-foundation.org, ast@kernel.org, bigeasy@linutronix.de,
cl@gentwo.org, clrkwllms@kernel.org,
david.hunter.linux@gmail.com, harry.yoo@oracle.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-rt-devel@lists.linux.dev, rientjes@google.com,
roman.gushchin@linux.dev, rostedt@goodmis.org,
skhan@linuxfoundation.org,
syzbot+b1546ad4a95331b2101e@syzkaller.appspotmail.com,
Hao Li <hao.li@linux.dev>
Subject: Re: [PATCH] slab: fix kmalloc_nolock() context check for PREEMPT_RT
Date: Mon, 5 Jan 2026 20:19:02 +0100 [thread overview]
Message-ID: <56598d76-02ca-490f-a100-0f223fb5717e@suse.cz> (raw)
In-Reply-To: <20251219135143.7337-1-swarajgaikwad1925@gmail.com>
On 12/19/25 14:51, Swaraj Gaikwad wrote:
> I agree that we can simplify this. I think !preemptible() would be
> the most descriptive choice here, as it directly expresses the
> constraint, we cannot take a sleeping lock when preemption is
> disabled.
> The updated check would be:
> if (IS_ENABLED(CONFIG_PREEMPT_RT) && !preemptible())
>
> I'll send a v2 with this change unless there are objections.
I think it's the best solution for now, so please do. We can change it back
later with sheaves, as Hao Li pointed out. It will limit PREEMPT_RT
kmalloc_nolock() for now. Steven explained to me it's the tracepoints
disabling preemption, but that will be also improved soon:
https://lore.kernel.org/all/20251219120607.7371034e@gandalf.local.home/
> Swaraj
next prev parent reply other threads:[~2026-01-05 19:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-19 8:57 Swaraj Gaikwad
2025-12-19 9:31 ` Vlastimil Babka
2025-12-19 13:29 ` Luis Claudio R. Goncalves
2025-12-19 13:51 ` Swaraj Gaikwad
2026-01-05 19:19 ` Vlastimil Babka [this message]
2025-12-19 15:22 ` Hao Li
2025-12-19 18:02 ` Luis Claudio R. Goncalves
2025-12-19 15:52 ` Vlastimil Babka
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