From nobody Sat Feb 7 18:52:24 2026 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 7028533A9D3 for ; Fri, 30 Jan 2026 15:46:24 +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=1769787984; cv=none; b=JjCIlHQ/fjkFDOtseDHLRTVOUnjjCE922GnsfSqN0ls1zemzCX2JNer9GAXEmFaA/kmUvntQllqQBQ/H0uQJ5UcYvjn05i5qIlcnM8JpguxiO6QDvHpNcOFbrhAYj70AxxRzLpYIXNCVoHlvvpWEdhlcM2Tb6MLylUldsBujJFE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769787984; c=relaxed/simple; bh=Xlz3vuMrnXgkGggrgNPyi5AUxFfxQY0cSm/GjnIcZac=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=t+jI+6ECNeJTtWzBHF+vI41hUAP/KnNVM1wfqczkTerdZ9wZ1q90CzDSUB7tKYwH269n3qt6bKgE/oXPICyzPa1XTD8jMi1/R6jBMIcQ31Vio9u58lPRU5IxaR3pwT1NHWAw1O40CCOnvbtTY1VhO/DlN8y0UuJNdXFzZWvam24= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OIexYOEh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OIexYOEh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D5ABC16AAE; Fri, 30 Jan 2026 15:46:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769787984; bh=Xlz3vuMrnXgkGggrgNPyi5AUxFfxQY0cSm/GjnIcZac=; h=Date:From:To:Cc:Subject:References:From; b=OIexYOEhu8FU88RudCVNzEztzfUZG4muWi0LC2Sqa1zMx2mSNJPwwkSvRTfNApFzD 2B8wHRzomXm7eqkI8Vvi2MtF9iHHPet0FbEqIbQ0moLlUV5ZRWfR2Y1pqM45u8+4IY HSguPNFMsfFMuq16+UFLFD2AI6ZfQn9AV2IyN7Fd4guKFK7WgjJ4W5UZOyufdSn6lZ XVJXbO2n6L+8gGTDYU6pRK1d4d7j/2OUKrHb5QD5vZo0edefuS11uHAjw2omMkBvwN cSgdp9REDk15PBwQlMkuJwQ4zHeY/923NpDlgDY20U1tcZ+7AZkAKSUtDTJGSnmK1J LMdwMU2oXaNFQ== Received: from rostedt by gandalf with local (Exim 4.99.1) (envelope-from ) id 1vlqhj-00000001gVT-3d4a; Fri, 30 Jan 2026 10:46:39 -0500 Message-ID: <20260130154639.720309344@kernel.org> User-Agent: quilt/0.68 Date: Fri, 30 Jan 2026 10:46:09 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , "Paul E. McKenney" , Sebastian Andrzej Siewior , Alexei Starovoitov , Alexei Starovoitov Subject: [for-next][PATCH 2/4] bpf: Have __bpf_trace_run() use rcu_read_lock_dont_migrate() References: <20260130154607.755725833@kernel.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 In order to switch the protection of tracepoint callbacks from preempt_disable() to srcu_read_lock_fast() the BPF callback from tracepoints needs to have migration prevention as the BPF programs expect to stay on the same CPU as they execute. Put together the RCU protection with migration prevention and use rcu_read_lock_dont_migrate() in __bpf_trace_run(). This will allow tracepoints callbacks to be preemptible. Link: https://lore.kernel.org/all/CAADnVQKvY026HSFGOsavJppm3-Ajm-VsLzY-OeFU= e+BaKMRnDg@mail.gmail.com/ Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: "Paul E. McKenney" Cc: Sebastian Andrzej Siewior Cc: Alexei Starovoitov Link: https://patch.msgid.link/20260126231256.335034877@kernel.org Suggested-by: Alexei Starovoitov Signed-off-by: Steven Rostedt (Google) --- kernel/trace/bpf_trace.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index fe28d86f7c35..abbf0177ad20 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2062,7 +2062,7 @@ void __bpf_trace_run(struct bpf_raw_tp_link *link, u6= 4 *args) struct bpf_run_ctx *old_run_ctx; struct bpf_trace_run_ctx run_ctx; =20 - cant_sleep(); + rcu_read_lock_dont_migrate(); if (unlikely(this_cpu_inc_return(*(prog->active)) !=3D 1)) { bpf_prog_inc_misses_counter(prog); goto out; @@ -2071,13 +2071,12 @@ void __bpf_trace_run(struct bpf_raw_tp_link *link, = u64 *args) run_ctx.bpf_cookie =3D link->cookie; old_run_ctx =3D bpf_set_run_ctx(&run_ctx.run_ctx); =20 - rcu_read_lock(); (void) bpf_prog_run(prog, args); - rcu_read_unlock(); =20 bpf_reset_run_ctx(old_run_ctx); out: this_cpu_dec(*(prog->active)); + rcu_read_unlock_migrate(); } =20 #define UNPACK(...) __VA_ARGS__ --=20 2.51.0