From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 5482638655B for ; Fri, 10 Jul 2026 05:39:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783661984; cv=none; b=YZr6/QthHEWjqnHYkekh1Bu4ee0wqYnWlFA4o2u1K6vroGwbwN6GCFc4l89P4SPr4akH3+3V+6oTxAVHYk1+gQVsaTJYMkuj+DqIKRU0ooyw+Z7GkcWISB8yhUTXzS1XFYgB5ty+hUb3fAUCpZN8smfFpSWVxfujIcDmlDi9VmM= 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=v0QsVANg; arc=none smtp.client-ip=209.85.214.202 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="v0QsVANg" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2cca5e0a0c9so9034525ad.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=1783661982; x=1784266782; 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=v0QsVANgLPgageztrhDGsp04lJihb6EVYdYt+Z4PfzGwPEyxVHdep/Kpv+08h1ax0Q lMDaZ9E5/pNTLtJMnRuPhmfrlq1THdczJ/X8810+aRbI/pyF/VXfD2mnWtgEBeyUh3c9 HtA25f+4OktnrbhT/BhGwDlEjfRaueR6tn2YyjNAku2jV9JiM5W5ab8qT+y3gEM2+WsE 5v96rPbfHqYHeVbxppEoqbmeOnvRlgdgFCeZ235nqIqfrDIITtUlxRhi/dtYslMCf84T I1PofafVLh/Y5lwFfU+0bs1rMeL9JOSVYNQUzro/pXDjbCcDX6iTyhplDp960D20xu5a +XVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783661982; x=1784266782; 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=D7Po3MYJHeYISRH77yHkhXQ/m1fhsjhh/MUvfJ56kPt0EOna3t4oVm+FIprE4TZDBd tC6yPIaubmlOdWXU2A2o2rlQMpzSFoacPCpqFXRpLce4iPTM9m6aFoF/M3T3tWjLk+MN VAQl9nRftvwBvOOeEP3dB7tS+zsLaTQsUCknJPmWUiwvyvIs6E890gC85OftGQx/4kyS be6yAJxdnUvHUF+VpCSfHtbPPqlOnYkXfRKFzn7946MxscHsNvjb5HMn+Q3Rb5pxIXwM i+//A/XU5xf5BoXDqHzRAolfI886Gzu9cDiCD6ELnwXYvwLbMorzUh1b52H9Qk+5i3Fw 8SrQ== X-Forwarded-Encrypted: i=1; AHgh+RoLTKt1kJyg6brVLRxcn8GXXGAWQgnBw1xQtz6Dmgoif5QrY7HlgnBtp+2aPpwNAjeMkXjjU9AsZMGpFW8=@vger.kernel.org X-Gm-Message-State: AOJu0Yz7UWH+33kO9Wd6Ro23bfMIhxp6ZSvkR9ZSZ+miUtCfF64428BU +7SfKCrYyfaiMz9K71qF9Daits3SyiE7rp5m0K6Ci9L159rsBoA/EN+IgUaq1RimWhWBEs1mBP3 +48lX7zneiw== 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-kernel@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