From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793586045; b=PN5laQ+iGymIlMwSw4sY9zOcrvidg3lQLRuf9D2n1VuxtL45VFrW84kUKEC3Wrhh5opz hKksdZeBJ8NmjdDbKOwFeQdAz3VBdevcUv7NxN+WG/yhSHVC3mbwmpoHJy/GiW5Y5aEAy aoQWsE8kvUEK2bRH18MMZHLFncHEgyKRHAgbF+5mqL7/XoOMAT1BCgqOJQyr1EI8CaCHW KZOh6+c7ueXhku77udwe5TzT2ftGih54ChRw8Sw6SrjReyUm3OW6PeKGPB6ZhVABruZR6 Sy5t4uScFXYn7LrHWERcnunrIkDdDnLO4v1wEObUnWDY8iC+1HJIn9pGJR2OQ3GiOLg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793586045; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=JSpJeOSCb1e+Nppl7Za1J3lhR0uIc6ZOwkyMf9Scmak=; b=VZSjIy6wqlnuUVnBEY3QA4l+9gvIDnhqAou3j0iroZbjIriLgKniu+5TALDaKZA8htV+ S+1x1WaL0vIsqC1Q1g8lHn3FEdhw1W3GCUhSYmXPpzfoCBGIKvZATc+kWjAclZLda3gpG /+c9KPMFx7G6+9dkwAgIWq+Avapb2lcJk7LsmNI4f3JFtzb5W8fgoV9lcsYgzS1TlQjZ6 m9dW3aMWzmHvYhZZZAaby8M2tGZ/yJEYGt+edACvvudPtJTQk9mf+QtlEAC1GbDRxFdKV tiskhyE6Cy1mT+TAVjq22eSuWVMXGTPH9J2LX5rbn4o3uLzuO58PyndR4gpnq7gFVZQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NiiqZyHl; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5EE4D606A327 for ; Mon, 2 Nov 2026 02:20:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NiiqZyHl Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD4F21F000C1; Mon, 2 Nov 2026 02:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793586045; bh=JSpJeOSCb1e+Nppl7Za1J3lhR0uIc6ZOwkyMf9Scmak=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=NiiqZyHlRghwqR5ftKb+vYNYvfQyDZNwHM/zluCPgJxX5gZpo5+vKx+NvPYC8ipCh 4egjv/Pqmpo0dGtkkP6nZb939bgPpUMHNp+pCAo3JONmlejJYYIGGJwAgtotwZvYOR imO0ONyIoNSup3upeVID9JbkZt9ZpqVyXBfR3QUyFP6G1Qqx5D+jCyy6LGuKd81G0c ihfZ9WB+NPD32nTF9EO6/bVGutk6yVxDf/jTfagbDE3uH1X6Lyjbp/tjAwe7hYLfqs avDYFnNchMyVfhVxgUPydm7OHYOCEuHv0D7OsYQe9nvRqOSN+HpuTIG7lDbQvF+oWA zx+BN+UR3u0zA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] perf/core: Prevent duplicate sigtrap task work enqueue Reply-To: sashiko-reviews@lists.linux.dev To: "Tengda Wu" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261102021355.650671-1-wutengda@huaweicloud.com> References: <20261102021355.650671-1-wutengda@huaweicloud.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 02 Nov 2026 02:20:44 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > The sigtrap handling in __perf_event_overflow() checks > event->pending_work before calling task_work_add(), but only sets > pending_work after the task work has been queued. >=20 > This leaves a window where an NMI can interrupt task_work_add() > and re-enter __perf_event_overflow() for the same event. Since > pending_work is still zero, the nested invocation can enqueue > the same pending_task again. >=20 > The re-entrant call path is: >=20 > __perf_event_overflow() > task_work_add() > kasan_record_aux_stack() > > [ ... ] > Also use READ_ONCE() when checking pending_work in the > exclude_kernel warning path to avoid an unsynchronized read. >=20 > Fixes: c5d93d23a260 ("perf: Enqueue SIGTRAP always via task_work.") > Signed-off-by: Tengda Wu Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102021355.6506= 71-1-wutengda@huaweicloud.com?part=3D1