From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41523386C3F for ; Fri, 10 Jul 2026 05:39:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783661984; cv=none; b=SojiMXegVeEOtRSz+xsjCp0K7OF08XXft8Y6YgZuC9l04IQyFeej1Ot4ojTlDde9lS0TAOGDA3Bc3ZM0MxOZPb6AqhsjAta8HEMg/BPX9jE4aX8zFq4X8tBbv015XSlwMGMl+MNjiHoqBI1YIG2/S9Ra+rZPDNAbU/oR9KGRSR0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783661984; c=relaxed/simple; bh=hTEFAHtxkuaJOBwCOhG+9+yK8Q/tIA2ju0Tfcl9tdKg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=GehrovGmwbfnHOZtZqgNugBpnS/se8j5YPCmJavk6L2pRKIwaevgkm1uNlVEgQFleXaSz2vXmfO6m/gCFVD3tsN3Lr48/CAgQQFGs/DTpF39KJqBVzMVdVb/InDRXvLl4zvVpI8+7UPBCmPsv6j8wwnOP6kWRPTUqqmgrx/fTTI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SfEs6EgG; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SfEs6EgG" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-384419c6c74so904464a91.1 for ; Thu, 09 Jul 2026 22:39:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1783661983; x=1784266783; darn=vger.kernel.org; h=content-type:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=dIZhNoNene1zs47xP+28Oq3PvnCrvAsWqTgfbnrd/A0=; b=SfEs6EgGPgrqRleYjmgQ0uapk8mQIjQ+w53aqdc49QaHe6YEcvYmumonp83gZbzhr6 bV2lBoJeigl9U3SlfGWFWc/aSooe1/WXiu7+kJ1Eo8Fwxw4J3IXpk3Wh32uYPMY8PjoE grhHm9CUzqtcgSUBqLrI/B7UBXHKGXSlxwhb0D1XMWWGIgvKOFl3w3a1JbWzpfsZOIB9 MXsaQ+Qd6m2qnSi3vtRxweK8TycEKY6urmhizC62n6Uo+YCfQdU7epulvzc2Y3JBlfQ0 GiemL7tLgVAIzQs4wO7vWU0OKAveJfj0cUSR3u6JG3Xt/Ma32u5+HJqDe7MEpCOJY5t3 PFAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783661983; x=1784266783; h=content-type:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=dIZhNoNene1zs47xP+28Oq3PvnCrvAsWqTgfbnrd/A0=; b=l+CBbkc5fJbMkhWPp7bqYyYioeh/HGnuCQM9oHFrBonEwiJA/bMaEHKdQNrjz7nXpd o+yz11uENEMlhQ5Pp63Q1ogmr7pZ3zi2NBDl6BbMN1eaEgPbUnQH1ExegZJ32BUpGanu nO6/mmIVz9fw/4uZ2xpP7F1CiOBBF+Vzt3UjMfkCloDR6/dzGCKGG2zMYCcGJp2AP48V /DMFHxJsPqnGiSwt4CWBlaspU0OtZUR7EY2sWthT3YdS+LuVhWhTQFnqsCauNO44+Vhq sd6kbLG/DyBMZSCSVLl74/2W2qI3GiFBF5x+hkO44sFQ6xGs/IQaQnpwhIjaVDR8HkQf ugFg== X-Forwarded-Encrypted: i=1; AHgh+Rpi4iafCbaRXMByBCisuFeZMjXKjdWuI2Efdc0jWm1p6Et6S3CZhEWBH31PpA6AF7jenzMPtdabiIpPhk4K2mTb@vger.kernel.org X-Gm-Message-State: AOJu0YxOns1jgopIk6avP7WbFbCpPf4hS+IKOTzPawrHxMCOJLDFL7mb aTM8RhOwrzcjStYlouNSDqJJNI8rx5ALV71oYPIwToIVbxfPIJz2SBnpA/JqrdSqDNRIYUuBV0u BoTXMYZzxCA== X-Received: from dldyq20-n1.prod.google.com ([2002:a05:701b:4554:10b0:139:f590:1d58]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:1c8f:b0:3b4:75c0:3ec0 with SMTP id adf61e73a8af0-3c0bca47f3cmr10871892637.30.1783661982459; Thu, 09 Jul 2026 22:39:42 -0700 (PDT) Date: Thu, 9 Jul 2026 22:39:07 -0700 In-Reply-To: <20260710053927.1864021-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260710053927.1864021-1-irogers@google.com> X-Mailer: git-send-email 2.55.0.795.g602f6c329a-goog Message-ID: <20260710053927.1864021-2-irogers@google.com> Subject: [PATCH v1 2/2] perf cap: If capability is missing still perform root test From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , Jiawei Sun , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Refine the capability checking logic in perf_cap__capable() to in the event the capability is missing do the fallback used_root test. Previously this was only performed when the capability syscall failed. Fixes: e25ebda78e23 ("perf cap: Tidy up and improve capability testing") Assisted-by: Antigravity:gemini-3.5-flash Signed-off-by: Ian Rogers --- tools/perf/util/cap.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/cap.c b/tools/perf/util/cap.c index ac6d1d9a523d..a2baecbc3145 100644 --- a/tools/perf/util/cap.c +++ b/tools/perf/util/cap.c @@ -20,6 +20,7 @@ bool perf_cap__capable(int cap, bool *used_root) }; struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {}; __u32 cap_val; + bool has_cap = false; *used_root = false; while (syscall(SYS_capget, &header, &data[0]) == -1) { @@ -37,12 +38,21 @@ bool perf_cap__capable(int cap, bool *used_root) if (cap >= 32) { if (header.version == _LINUX_CAPABILITY_VERSION_3) { cap_val = data[1].effective; + has_cap = (cap_val & (1U << (cap & 0x1f))) != 0; } else { /* Capability beyond 32 is requested but only 32 are supported. */ - return false; + has_cap = false; } } else { cap_val = data[0].effective; + has_cap = (cap_val & (1U << (cap & 0x1f))) != 0; } - return (cap_val & (1 << (cap & 0x1f))) != 0; + + if (has_cap) { + *used_root = false; + return true; + } + + *used_root = true; + return geteuid() == 0; } -- 2.55.0.795.g602f6c329a-goog