From: sashiko-bot@kernel.org
To: "Ravi Bangoria" <ravi.bangoria@amd.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 2/3] perf/amd/ibs: Fix kernel address leak via REGS_USER
Date: Thu, 15 Oct 2026 06:13:47 +0000 [thread overview]
Message-ID: <sashiko-outbox-172333@kernel.org> (raw)
In-Reply-To: <20261015060430.5877-3-ravi.bangoria@amd.com>
> IBS hardware captures a sample and raises an NMI. Since the NMI can be
> delivered with a delay, a privilege change may occur between sample
> capture and NMI delivery. Because IBS only provides the sample RIP, the
> kernel records GPRs from the NMI pt_regs, which may reflect kernel mode
> if a privilege switch occurred in the interim. This can leak kernel
> addresses to unprivileged users through PERF_SAMPLE_REGS_USER.
>
> Fix this by discarding samples where the NMI arrives in kernel mode and
> the user has set exclude_kernel.
>
> Reported-by: Jayapal Ashwin Nair <janair@amd.com>
> Fixes: d29e744c7167 ("perf/x86: Relax privilege filter restriction on AMD IBS")
> Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261015060430.5877-1-ravi.bangoria@amd.com?part=2
next prev parent reply other threads:[~2026-10-15 6:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-15 6:04 [PATCH 0/3] perf/amd/ibs: Assorted fixes Ravi Bangoria
2026-10-15 6:04 ` [PATCH 1/3] perf/amd/ibs: Reset CPU0 IBS state on syscore resume Ravi Bangoria
2026-10-15 6:15 ` sashiko-bot
2026-10-15 6:04 ` [PATCH 2/3] perf/amd/ibs: Fix kernel address leak via REGS_USER Ravi Bangoria
2026-10-15 6:13 ` sashiko-bot [this message]
2026-10-15 6:04 ` [PATCH 3/3] perf/amd/ibs: Simplify event state handling with IBS_CAPS_DIS Ravi Bangoria
2026-10-15 6:24 ` sashiko-bot
2026-10-15 6:49 ` Ravi Bangoria
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