From mboxrd@z Thu Jan 1 00:00:00 1970 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 8DCEA3815E1; Fri, 8 May 2026 09:03:32 +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=1778231012; cv=none; b=l/hs9sphFngc372JEkOBr2L1wPONldH1iMa0WazDY3g4v0Fam6KP19CxkVEXnmY7Y1XIO8oA8UzD3VTThr2R6r15m1MLiJXq6k1eKVE1a38EnfDQCg6wnd7JWsp+BhB7I0ZxcBHbGvBl8r8Nwc/y12wa5AcxpD5SDmy0VnWeINk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778231012; c=relaxed/simple; bh=sI4KlbwGOk77SXPZS0f98Lx3I2yyUnIH5LrfDk6EqOY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=icVWt3jkaETy1Nc1D/tghuI44NBR+zKHkS4yiWYAhAzENCYdux0SAmEIIHC5lNOpCluhneA95EIsibPj38ClYqdwRpS9tqO/alHopUEJpqCWHFBoJ5B3At43BiSHZD5/xYHHnHQu8Imegu/0xH3XWGHtMbt6IB3GssxDZVyPo+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T22GXDCA; 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="T22GXDCA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33685C2BCFB; Fri, 8 May 2026 09:03:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778231012; bh=sI4KlbwGOk77SXPZS0f98Lx3I2yyUnIH5LrfDk6EqOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T22GXDCAQ8knidISGcDa49K8IN2g99tT6fYnUlS4NOZs3/CN8bbPlrZnO5vILs2PP 7G+gdkNYMafyCsnIGDPTOF/ZWxBb56H+G0MvAOT9ZMLREMrcdg865AyYgoMnkFn2F+ V3iml5+d0kzNcqs5RyLcaHjLl31p6w0edRUdfLz5305AvvyL7bofQUAcgZSaPsgXMU mPJ1o7y9xrJ35WqmDlsXDjdmp3CPBFHksVImXktihuv4X2T8nPmhekeWu57s3QGXaQ M46XuQlDwX0f+PxX7viasLzkV56eHEp8NKiBPn178QTYDPPMEDGPdCrfjzezrFXmt0 v4EOvOvPluEWQ== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1wLH7K-00000001ahA-03my; Fri, 08 May 2026 11:03:30 +0200 From: Johan Hovold To: Wolfram Sang Cc: Andi Shyti , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org Subject: [PATCH v2 6/9] i2c: core: fix adapter registration race Date: Fri, 8 May 2026 11:03:08 +0200 Message-ID: <20260508090311.379333-7-johan@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260508090311.379333-1-johan@kernel.org> References: <20260508090311.379333-1-johan@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: 8bit Adapters can be looked up based on their id using i2c_get_adapter() which takes a reference to the embedded struct device. Make sure that the adapter (including its struct device) has been initialised before adding it to the IDR to avoid accessing uninitialised data which could, for example, lead to NULL-pointer dereferences or use-after-free. Note that the i2c-dev chardev, which is registered from a bus notifier, currently uses i2c_get_adapter() so the adapter needs to be added to the IDR before registration. Fixes: 6e13e6418418 ("i2c: Add i2c_add_numbered_adapter()") Cc: stable@vger.kernel.org # 2.6.22 Signed-off-by: Johan Hovold --- drivers/i2c/i2c-core-base.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 20d48cb84a6c..4863d660faf6 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1577,6 +1577,10 @@ static int i2c_register_adapter(struct i2c_adapter *adap) adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root); + mutex_lock(&core_lock); + idr_replace(&i2c_adapter_idr, adap, adap->nr); + mutex_unlock(&core_lock); + res = device_add(&adap->dev); if (res) { pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); @@ -1635,7 +1639,7 @@ static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) int id; mutex_lock(&core_lock); - id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); + id = idr_alloc(&i2c_adapter_idr, NULL, adap->nr, adap->nr + 1, GFP_KERNEL); mutex_unlock(&core_lock); if (WARN(id < 0, "couldn't get idr")) return id == -ENOSPC ? -EBUSY : id; @@ -1669,7 +1673,7 @@ int i2c_add_adapter(struct i2c_adapter *adapter) } mutex_lock(&core_lock); - id = idr_alloc(&i2c_adapter_idr, adapter, + id = idr_alloc(&i2c_adapter_idr, NULL, __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); mutex_unlock(&core_lock); if (WARN(id < 0, "couldn't get idr")) -- 2.53.0