[PATCH 6.6 023/122] cxl/core/regs: Fix usage of map->reg_type in cxl_decode_regblock() before assigned

Greg Kroah-Hartman
2024-04-15T14:33:18Z

From: Dave Jiang <dave.jiang@intel.com>

[ Upstream commit 5c88a9ccd4c431d58b532e4158b6999a8350062c ]

In the error path, map->reg_type is being used for kernel warning
before its value is setup. Found by code inspection. Exposure to
user is wrong reg_type being emitted via kernel log. Use a local
var for reg_type and retrieve value for usage.

Fixes: 6c7f4f1e51c2 ("cxl/core/regs: Make cxl_map_{component, device}_regs() device generic")
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/cxl/core/regs.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index e0fbe964f6f0a..bab4592db647f 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -271,6 +271,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_map_device_regs, CXL);
static bool cxl_decode_regblock(struct pci_dev *pdev, u32 reg_lo, u32 reg_hi,
struct cxl_register_map *map)
{
+ u8 reg_type = FIELD_GET(CXL_DVSEC_REG_LOCATOR_BLOCK_ID_MASK, reg_lo);
int bar = FIELD_GET(CXL_DVSEC_REG_LOCATOR_BIR_MASK, reg_lo);
u64 offset = ((u64)reg_hi << 32) |
(reg_lo & CXL_DVSEC_REG_LOCATOR_BLOCK_OFF_LOW_MASK);
@@ -278,11 +279,11 @@ static bool cxl_decode_regblock(struct pci_dev *pdev, u32 reg_lo, u32 reg_hi,
if (offset > pci_resource_len(pdev, bar)) {
dev_warn(&pdev->dev,
"BAR%d: %pr: too small (offset: %pa, type: %d)\n", bar,
- &pdev->resource[bar], &offset, map->reg_type);
+ &pdev->resource[bar], &offset, reg_type);
return false;
}

- map->reg_type = FIELD_GET(CXL_DVSEC_REG_LOCATOR_BLOCK_ID_MASK, reg_lo);
+ map->reg_type = reg_type;
map->resource = pci_resource_start(pdev, bar) + offset;
map->max_size = pci_resource_len(pdev, bar) - offset;
return true;
--
2.43.0