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From: Tejun Heo <tj@kernel•org>
To: bot+bpf-ci@kernel•org, void@manifault•com, arighi@nvidia•com,
	changwoo@igalia•com, ast@kernel•org, andrii@kernel•org,
	daniel@iogearbox•net, martin.lau@linux•dev, memxor@gmail•com
Cc: peterz@infradead•org, catalin.marinas@arm•com, will@kernel•org,
	tglx@kernel•org, mingo@redhat•com, bp@alien8•de,
	dave.hansen@linux•intel.com, akpm@linux-foundation•org,
	david@kernel•org, rppt@kernel•org, emil@etsalapatis•com,
	sched-ext@lists•linux.dev, bpf@vger•kernel.org, x86@kernel•org,
	linux-arm-kernel@lists•infradead.org, linux-mm@kvack•org,
	linux-kernel@vger•kernel.org, eddyz87@gmail•com,
	yonghong.song@linux•dev, clm@meta•com, ihor.solodrai@linux•dev
Subject: Re: [PATCH bpf-next] bpf: Replace scratch PTE atomically when allocating arena pages
Date: Tue, 02 Jun 2026 12:09:11 -1000	[thread overview]
Message-ID: <8f133924fbf8d259340f3057e505f663@kernel.org> (raw)
In-Reply-To: <f45f02410d23c99d14f3577da9b27a327816b5a0904bdeefc8e229eac760d1cf@mail.kernel.org>

On Mon, Jun 01, 2026 at 08:15:34PM +0000, bot+bpf-ci@kernel•org wrote:
> After the real page is installed without a flush, can that stale
> kaddr -> scratch_page translation persist, so that later kernel-side
> accesses at kaddr reach the shared per-arena scratch page instead of
> the freshly allocated page?

It can on x86, but it's harmless: that CPU faulted on an unallocated
address and got scratch-recovered, so reaching either the scratch or the
real page is fine. No flush needed.

Thanks.

--
tejun


  reply	other threads:[~2026-06-02 22:09 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-01 18:37 [PATCH bpf-next] bpf: Replace scratch PTE atomically when allocating arena pages Tejun Heo
2026-06-01 20:15 ` bot+bpf-ci
2026-06-02 22:09   ` Tejun Heo [this message]
2026-06-02 22:29 ` Kumar Kartikeya Dwivedi

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