From: Will Deacon <will@kernel.org>
To: Fredrik Markstrom <fredrik.markstrom@est.tech>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Shuah Khan <shuah@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
Olof Johansson <olof@lixom.net>, Tony Lindgren <tony@atomide.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-perf-users@vger.kernel.org,
Nicolas Pitre <nico@fluxnic.net>,
Ivar Holmqvist <ivar.holmqvist@est.tech>,
Malin Jonsson <malin.jonsson@est.tech>
Subject: Re: [PATCH v2 0/3] arm64: perf: Skip device memory during user callchain unwinding
Date: Mon, 18 May 2026 16:06:11 +0100 [thread overview]
Message-ID: <agsq4wZMGth-T3BG@willie-the-truck> (raw)
In-Reply-To: <20260430-master-with-pfix-v3-v2-0-bd526ec04a75@est.tech>
On Thu, Apr 30, 2026 at 12:55:12PM +0200, Fredrik Markstrom wrote:
> Perf callchain unwinding follows userspace frame pointers via
> copy_from_user. A corrupted or malicious frame pointer can point
> into device I/O memory mapped into the process (e.g. via UIO or
> /dev/mem), causing the kernel to read from MMIO regions in PMU
> interrupt context. Such reads can have side effects on hardware
> (clearing status registers, advancing FIFOs, triggering DMA) and
> on arm64 can produce a synchronous external abort that panics the
> kernel.
Hmm, but why is unwinding special in this case? If userspace has access
to sensitive MMIO/device mappings, it can presumably pass them to
syscalls and trigger crashes all over the place?
Will
next prev parent reply other threads:[~2026-05-18 15:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-30 10:55 [PATCH v2 0/3] arm64: perf: Skip device memory during user callchain unwinding Fredrik Markstrom
2026-04-30 10:55 ` [PATCH v2 1/3] " Fredrik Markstrom
2026-05-01 9:54 ` Fredrik Markstrom
2026-04-30 10:55 ` [PATCH v2 2/3] DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory callchain guard Fredrik Markstrom
2026-04-30 10:55 ` [PATCH v2 3/3] DO NOT MERGE: selftests: perf_events: Add device memory callchain unwinding test Fredrik Markstrom
2026-05-18 15:06 ` Will Deacon [this message]
2026-05-19 8:25 ` [PATCH v2 0/3] arm64: perf: Skip device memory during user callchain unwinding Fredrik Markstrom
2026-06-11 10:32 ` Fredrik Markstrom
2026-06-19 15:31 ` Will Deacon
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