From: sashiko-bot@kernel.org
To: Paul <p@1g4.org>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] perf record: reject CPU indices equal to the mask size
Date: Fri, 30 Oct 2026 06:59:58 +0000 [thread overview]
Message-ID: <sashiko-outbox-190624@kernel.org> (raw)
In-Reply-To: <20261030064825.2156317-1-p@1g4.org>
> From: Paul Moses <p@1g4.org>
>
> record__mmap_cpu_mask_init() rejects CPU indices greater than nbits but
> accepts nbits itself. Valid indices end at nbits - 1. When nbits is a
> multiple of BITS_PER_LONG, __set_bit() accesses the word immediately past
> the bitmap allocation.
>
> User specified recording thread masks reach this write before they are
> intersected with the selected CPU mask. For example, an affinity mask
> containing CPU 64 overruns a bitmap allocated for 64 possible CPUs.
>
> ==40343==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7bbab4000018 at pc 0x6195de57af45 bp 0x7ffe25545d20 sp 0x7ffe25545d18
> READ of size 8 at 0x7bbab4000018 thread T0
>
> Reject indices greater than or equal to nbits before setting a bit.
>
> Fixes: cbd7bfc7fd99 ("tools/perf: Fix out of bound access to cpu mask array")
> Cc: stable@vger.kernel.org
> Signed-off-by: Paul Moses <p@1g4.org>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261030064825.2156317-1-p@1g4.org?part=1
next prev parent reply other threads:[~2026-10-30 6:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-30 6:48 [PATCH] perf record: reject CPU indices equal to the mask size Paul
2026-10-30 6:59 ` sashiko-bot [this message]
2026-11-06 7:20 ` Namhyung Kim
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