[PATCH] cxl/region: Reject delete of a provider-locked region
Richard Cheng <[email protected]>
| Newsgroups | org.kernel.vger.linux-cxl,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
delete_region_store() destroys a region object without checking CXL_REGION_F_LOCK, unlike commit_store() which refuses locked regions with -EPERM. A region owned by a memdev-attach provider carries F_LOCK, and cxl_region_decode_reset() deliberately skips the HDM decoder reset for F_LOCK regions. As a result, a userspace write to delete_region tears down the region object but leaves the endpoint HDM decoder committed with no owning region, which is an orphan, enabled decoder. Gate delete_region_store() on CXL_REGION_F_LOCK. Signed-off-by: Richard Cheng <[email protected]> --- drivers/cxl/core/region.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 578622240401..cfc9622c9309 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2894,6 +2894,9 @@ static ssize_t delete_region_store(struct device *dev, if (!cxlr || !sysfs_streq(buf, dev_name(&cxlr->dev))) return -ENODEV; + if (test_bit(CXL_REGION_F_LOCK, &cxlr->flags)) + return -EPERM; + unregister_region(cxlr); return len; base-commit: 5ca04f3ba91f1773bbd5da6d9c654ccc1ba7831d -- 2.43.0