linux-kernel - [PATCH v3] cxl/core: Return error when cxl_endpoint_gather

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241022030054.258942-1-lizhijian@fujitsu.com>
Date: Tue, 22 Oct 2024 11:00:54 +0800
From: Li Zhijian <lizhijian@...itsu.com>
To: linux-cxl@...r.kernel.org
Cc: Davidlohr Bueso <dave@...olabs.net>,
	Jonathan Cameron <jonathan.cameron@...wei.com>,
	Dave Jiang <dave.jiang@...el.com>,
	Alison Schofield <alison.schofield@...el.com>,
	Vishal Verma <vishal.l.verma@...el.com>,
	Ira Weiny <ira.weiny@...el.com>,
	Dan Williams <dan.j.williams@...el.com>,
	linux-kernel@...r.kernel.org,
	Li Zhijian <lizhijian@...itsu.com>,
	"Huang, Ying" <ying.huang@...el.com>
Subject: [PATCH v3] cxl/core: Return error when cxl_endpoint_gather_bandwidth() handles a non-PCI device

The function cxl_endpoint_gather_bandwidth() invokes
pci_bus_read/write_XXX(), however, not all CXL devices are presently
implemented via PCI. It is recognized that the cxl_test has realized a CXL
device using a platform device.

Calling pci_bus_read/write_XXX() in cxl_test will cause kernel panic:
 platform cxl_host_bridge.3: host supports CXL (restricted)
 Oops: general protection fault, probably for non-canonical address 0x3ef17856fcae4fbd: 0000 [#1] PREEMPT SMP PTI
 Call Trace:
  <TASK>
  ? __die_body.cold+0x19/0x27
  ? die_addr+0x38/0x60
  ? exc_general_protection+0x1f5/0x4b0
  ? asm_exc_general_protection+0x22/0x30
  ? pci_bus_read_config_word+0x1c/0x60
  pcie_capability_read_word+0x93/0xb0
  pcie_link_speed_mbps+0x18/0x50
  cxl_pci_get_bandwidth+0x18/0x60 [cxl_core]
  cxl_endpoint_gather_bandwidth.constprop.0+0xf4/0x230 [cxl_core]
  ? xas_store+0x54/0x660
  ? preempt_count_add+0x69/0xa0
  ? _raw_spin_lock+0x13/0x40
  ? __kmalloc_cache_noprof+0xe7/0x270
  cxl_region_shared_upstream_bandwidth_update+0x9c/0x790 [cxl_core]
  cxl_region_attach+0x520/0x7e0 [cxl_core]
  store_targetN+0xf2/0x120 [cxl_core]
  kernfs_fop_write_iter+0x13a/0x1f0
  vfs_write+0x23b/0x410
  ksys_write+0x53/0xd0
  do_syscall_64+0x62/0x180
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

And Ying also reported a KASAN error with similar calltrace.

Reported-by: "Huang, Ying" <ying.huang@...el.com>
Closes: http://lore.kernel.org/87y12w9vp5.fsf@yhuang6-desk2.ccr.corp.intel.com
Fixes: a5ab0de0ebaa ("cxl: Calculate region bandwidth of targets with shared upstream link")
Signed-off-by: Li Zhijian <lizhijian@...itsu.com>
Reviewed-by: Dan Williams <dan.j.williams@...el.com>
---
V3:
  update return code to ENODEV and change logs #Dan

V2:
  Check device type in original cxl_endpoint_gather_bandwidth() instead of mocking a new one. # Dan
  Also noticed that the existing cxl_switch_gather_bandwidth() also have the same check.
---
 drivers/cxl/core/cdat.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index ef1621d40f05..e9cd7939c407 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -641,6 +641,9 @@ static int cxl_endpoint_gather_bandwidth(struct cxl_region *cxlr,
 	void *ptr;
 	int rc;

+	if (!dev_is_pci(cxlds->dev))
+		return -ENODEV;
+
 	if (cxlds->rcd)
 		return -ENODEV;

-- 
2.44.0