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From: David Arcari <darcari@redhat.com>
To: lenb@kernel.org
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	David Arcari <darcari@redhat.com>
Subject: [PATCH 0/3] tools/power turbostat: Fix segfault and restart loop issues
Date: Tue, 18 Nov 2025 10:58:10 -0500	[thread overview]
Message-ID: <20251118155813.533424-1-darcari@redhat.com> (raw)

This patch series addresses three stability issues found in turbostat,
primarily affecting virtualized environments where specific hardware
counters (like APERF) or MSR access may be restricted or inconsistent.

Patch 1 fixes a segmentation fault caused by referencing a NULL
fd_instr_count_percpu pointer. This occurs on systems where has_aperf
is 0 (preventing allocation), but has_aperf_access is 1 (allowing the
function call).

Patch 2 prevents an infinite loop when turbostat attempts to restart.
It ensures the restart limit is checked in all error paths and removes
logic that incorrectly reset the retry counter.

Patch 3 allows turbostat to proceed gracefully when APERF is unavailable.
Previously, the missing counter caused delta_thread() to error out,
triggering the restart mechanism.


David Arcari (3):
  tools/power turbostat: avoid segfault referencing
    fd_instr_count_percpu
  tools/power turbostat: avoid an infinite loop of restarts
  tools/power turbostat: allow turbostat to work when aperf is not
    available

 tools/power/x86/turbostat/turbostat.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

-- 
2.51.0


             reply	other threads:[~2025-11-18 15:58 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-18 15:58 David Arcari [this message]
2025-11-18 15:58 ` [PATCH 1/3] tools/power turbostat: avoid segfault referencing fd_instr_count_percpu David Arcari
2025-11-25 19:11   ` Len Brown
2025-12-01 14:13     ` David Arcari
2025-11-18 15:58 ` [PATCH 2/3] tools/power turbostat: avoid an infinite loop of restarts David Arcari
2025-11-25 19:12   ` Len Brown
2025-11-25 21:50     ` David Arcari
2025-11-27 17:45       ` Len Brown
2025-12-01 12:18         ` David Arcari
2025-11-18 15:58 ` [PATCH 3/3] tools/power turbostat: allow turbostat to work when aperf is not available David Arcari
2025-11-25 19:14   ` Len Brown
2025-11-25 21:55     ` David Arcari
2025-12-01 15:13       ` David Arcari
2025-12-01 19:53         ` Len Brown
2025-12-01 20:11           ` Len Brown
2025-12-02 12:55             ` David Arcari
2025-12-02 15:02               ` Len Brown

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