From nobody Tue Oct 7 21:44:28 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 18FC42417F0; Fri, 9 May 2025 16:51:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746809501; cv=none; b=Tj4CaviKEcS+j016s6zHgScbBfNSqHMjVc5qOS3acHVVtPpeEylaEg4MvQG0iJJxtKP/opXwRLGCxxgmysNRHFM+9Ig55vogaMIsoxYX4Q9A8zlWpwLS/QYX+xlsYPpM/FJmX+ZB+4rKRjGp957TlBR51o9zPaQLHIj+9VI7rrU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746809501; c=relaxed/simple; bh=HGrKuS39xLJq83enXt1f+CmV81NnDU+NNzgmZrHZ28Q=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=b1yLZrLXND8D1fJguabzokXmVrXq9ka/p2ND23lHCPqk49P3hZuW7L+4lGm4jhWuRqKOccMJAVhAnZ+0wNloWDbx7ykGZUUIwbjngnwJWuf4L3/CvejaStWpalXWFtEWE7tAP8p27weikDTVzBeWaO8FmRRFC0upFj3rPK4gvjk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5B3DC4CEF1; Fri, 9 May 2025 16:51:40 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1uDQx2-00000002gLE-1ttz; Fri, 09 May 2025 12:51:56 -0400 Message-ID: <20250509165156.309890035@goodmis.org> User-Agent: quilt/0.68 Date: Fri, 09 May 2025 12:45:40 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Namhyung Kim Subject: [PATCH v8 16/18] perf: Use current->flags & PF_KTHREAD instead of current->mm == NULL References: <20250509164524.448387100@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Rostedt To determine if a task is a kernel thread or not, it is more reliable to use (current->flags & PF_KTHREAD) than to rely on current->mm being NULL. That is because some kernel tasks (io_uring helpers) may have a mm field. Link: https://lore.kernel.org/linux-trace-kernel/20250424163607.GE18306@noi= sy.programming.kicks-ass.net/ Signed-off-by: Steven Rostedt (Google) --- kernel/events/callchain.c | 6 +++--- kernel/events/core.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index abf258913ab6..cda145dc11bd 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -246,10 +246,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel,= bool user, =20 if (user) { if (!user_mode(regs)) { - if (current->mm) - regs =3D task_pt_regs(current); - else + if (current->flags & PF_KTHREAD) regs =3D NULL; + else + regs =3D task_pt_regs(current); } =20 if (regs) { diff --git a/kernel/events/core.c b/kernel/events/core.c index 0bac8cae08a8..7c7d5a27c568 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7989,7 +7989,7 @@ static u64 perf_virt_to_phys(u64 virt) * Try IRQ-safe get_user_page_fast_only first. * If failed, leave phys_addr as 0. */ - if (current->mm !=3D NULL) { + if (!(current->flags & PF_KTHREAD)) { struct page *p; =20 pagefault_disable(); --=20 2.47.2