diff options
| -rw-r--r-- | drivers/pci/controller/pci-hyperv.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 910fa016d095..be99862166d0 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2902,9 +2902,27 @@ static int hv_pci_probe(struct hv_device *hdev, * hv_pcibus_device contains the hypercall arguments for retargeting in * hv_irq_unmask(). Those must not cross a page boundary. */ - BUILD_BUG_ON(sizeof(*hbus) > PAGE_SIZE); + BUILD_BUG_ON(sizeof(*hbus) > HV_HYP_PAGE_SIZE); - hbus = (struct hv_pcibus_device *)get_zeroed_page(GFP_KERNEL); + /* + * With the recent 59bb47985c1d ("mm, sl[aou]b: guarantee natural + * alignment for kmalloc(power-of-two)"), kzalloc() is able to allocate + * a 4KB buffer that is guaranteed to be 4KB-aligned. Here the size and + * alignment of hbus is important because hbus's field + * retarget_msi_interrupt_params must not cross a 4KB page boundary. + * + * Here we prefer kzalloc to get_zeroed_page(), because a buffer + * allocated by the latter is not tracked and scanned by kmemleak, and + * hence kmemleak reports the pointer contained in the hbus buffer + * (i.e. the hpdev struct, which is created in new_pcichild_device() and + * is tracked by hbus->children) as memory leak (false positive). + * + * If the kernel doesn't have 59bb47985c1d, get_zeroed_page() *must* be + * used to allocate the hbus buffer and we can avoid the kmemleak false + * positive by using kmemleak_alloc() and kmemleak_free() to ask + * kmemleak to track and scan the hbus buffer. + */ + hbus = (struct hv_pcibus_device *)kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL); if (!hbus) return -ENOMEM; hbus->state = hv_pcibus_init; @@ -3133,7 +3151,7 @@ static int hv_pci_remove(struct hv_device *hdev) hv_put_dom_num(hbus->sysdata.domain); - free_page((unsigned long)hbus); + kfree(hbus); return ret; } |