From nobody Fri Oct 2 03:03:43 2026 Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (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 D033E47DD59 for ; Wed, 5 Aug 2026 15:32:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.69 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785943962; cv=none; b=UNU/7HL4PDWoq+AEV/MoeyaltF4MThm7qheUrAl4m9NZSxzQkXK3UJBxPOENpYWV30mv6HE4w1rsMbQqxf+iw9TcLyPOkaL+UhzwQgYnh6Zbj6mkiYJtIi54h+/HbJe3W6/7MAEEDKfyDwR22ZsRwxQdnIfr1wxa/TpgZq7h+XM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785943962; c=relaxed/simple; bh=fSfHKUXXjeuaF5GoHZqzt3ghM/ntROBEcVxwVLLKf5c=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=t554nrHpj8BDxKucI3dOJ3QoieyAnb+emwJjp3tjNQf6BDZiCeP3XDno/fP/3AFeHpGP7R4clrsPXAFIpzSblnQccj+69dzEHjW6329bUxL2NNdp9RkGNHyhYL/95sicc2Swb9jUekR7DKSU6HagZ85V8mCa+bXY6Sf5AxJpTxw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=stizqqRa; arc=none smtp.client-ip=209.85.221.69 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--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="stizqqRa" Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-47f810c8aebso669528f8f.2 for ; Wed, 05 Aug 2026 08:32:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785943956; x=1786548756; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:mime-version:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=dURYyTAr3xD5Ug+KUce+nub8IT6QTcigszEQZYZJDrw=; b=stizqqRanQgIpndQuGOLsWECD1eUKSphGBcuRy9HaX7RvLdQAeBkQTPHvabUKA8hfM 9H5FlYe9l2D+Bvc61C8ae0/JTEc9i0P73nXSZJLfcYcaUZkVoVOH+kHnEiqI0FKojpUM jnD2zGqeC9f35TdYO4ttmecm4dg7al1bpIavSfuoDesmWtbxCYY2ih6M/E3R13u5mJBi HSqq2X8Bth7811djhAb17gR01dmYkJhdfeBBPYAFIzq9Ge+ogTeAgcQl50qbjHKA3ptz LcuV5JohOUXogHZ2UZuLpvHTIMSsGtTq2/GL9cdWuPBJvn0XpWMNaUcs9gZJFFKwezCR AOFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785943956; x=1786548756; h=content-type:cc:to:from:subject:message-id:mime-version:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=dURYyTAr3xD5Ug+KUce+nub8IT6QTcigszEQZYZJDrw=; b=hxfZ8zqpAmIDICv+8GmmveH7Oie/YCKnpYova1tk1iFpSi4K7BOWD8tT6flHZ4SXCL Jm6wF4I9Mqomc06xGDhw/235qnZnRezLliwSyl0kJvwyYrpd1QYeCLw3nfkZEa81qhHh JwPQLxR1U9XUXV5JWYtcSISOI8BsNRM11v6gtO5XFYwml8ALlftQaOcSmWLqYMCbZaZ8 2L9zT8APyubjdqp6AP+towAE4VcI6upK49gkooQo0xjcHsFA9+a74H8UuaYSwi48GKlf i8P+Uz19lXzEt9VgUUk8Jf77kTimzotPJ0D1VIgwW887R0HioOiBGcmnGSMNRlheSvY+ VQUg== X-Forwarded-Encrypted: i=1; AHgh+RprioWDDkk73DkRJxkPM2jWn8bK8nM5+jlSwk44axsKz5zd3C1Wu19CiCkuwdSdEzoEwuLgpM2c+JiFkH0=@vger.kernel.org X-Gm-Message-State: AOJu0YyWLJwaj4b9vhvXlLVhMOvGR3nKH5MkBN2VO840Ujo9ipUPW/9S siZ153xqjyiBTfNgoqoyd1OzVSIZfL7fb2bMq8uBq/vnS0PoCLKpVzDKd8rFh9rx0mhymh3xZyG +sLy2ze6LYIptMrulihtEeQ== X-Received: from wmby14.prod.google.com ([2002:a05:600c:c04e:b0:495:3c12:fb52]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4595:b0:498:952:e276 with SMTP id 5b1f17b1804b1-4994e79e377mr64342435e9.8.1785943955841; Wed, 05 Aug 2026 08:32:35 -0700 (PDT) Date: Wed, 5 Aug 2026 16:32:24 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.571.g244d577d93-goog Message-ID: <20260805153225.2096152-1-vdonnefort@google.com> Subject: [PATCH] ring-buffer: Prevent subbuf order change when resizing is disabled From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort , syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Because ring_buffer_subbuf_order_set() frees buffer pages, we can't allow it when risizing is disabled. A non-consuming reader is at risk of use-after-free (rb_advance_iter()). Return -EBUSY on resize_disabled, matching ring_buffer_resize() behaviour. Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page= ") Reported-by: syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 8e2485bb3aa8..414bca2121a7 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7358,7 +7358,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer = *buffer, int order) =20 cpu_buffer =3D buffer->buffers[cpu]; =20 - if (cpu_buffer->mapped) { + if (atomic_read(&cpu_buffer->resize_disabled)) { err =3D -EBUSY; goto error; } base-commit: 075b74841bd0065a3bda3440873c747938e69b68 --=20 2.55.0.571.g244d577d93-goog