6.12-stable review patch. If anyone has any objections, please let me know.
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From: Yi Liu yi.l.liu@intel.com
commit 74536f91962d5f6af0a42414773ce61e653c10ee upstream.
The qi_batch is allocated when assigning cache tag for a domain. While for nested parent domain, it is missed. Hence, when trying to map pages to the nested parent, NULL dereference occurred. Also, there is potential memleak since there is no lock around domain->qi_batch allocation.
To solve it, add a helper for qi_batch allocation, and call it in both the __cache_tag_assign_domain() and __cache_tag_assign_parent_domain().
BUG: kernel NULL pointer dereference, address: 0000000000000200 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8104795067 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 223 UID: 0 PID: 4357 Comm: qemu-system-x86 Not tainted 6.13.0-rc1-00028-g4b50c3c3b998-dirty #2632 Call Trace: ? __die+0x24/0x70 ? page_fault_oops+0x80/0x150 ? do_user_addr_fault+0x63/0x7b0 ? exc_page_fault+0x7c/0x220 ? asm_exc_page_fault+0x26/0x30 ? cache_tag_flush_range_np+0x13c/0x260 intel_iommu_iotlb_sync_map+0x1a/0x30 iommu_map+0x61/0xf0 batch_to_domain+0x188/0x250 iopt_area_fill_domains+0x125/0x320 ? rcu_is_watching+0x11/0x50 iopt_map_pages+0x63/0x100 iopt_map_common.isra.0+0xa7/0x190 iopt_map_user_pages+0x6a/0x80 iommufd_ioas_map+0xcd/0x1d0 iommufd_fops_ioctl+0x118/0x1c0 __x64_sys_ioctl+0x93/0xc0 do_syscall_64+0x71/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: 705c1cdf1e73 ("iommu/vt-d: Introduce batched cache invalidation") Cc: stable@vger.kernel.org Co-developed-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Yi Liu yi.l.liu@intel.com Reviewed-by: Kevin Tian kevin.tian@intel.com Link: https://lore.kernel.org/r/20241210130322.17175-1-yi.l.liu@intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/intel/cache.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/intel/cache.c b/drivers/iommu/intel/cache.c index e5b89f728ad3..09694cca8752 100644 --- a/drivers/iommu/intel/cache.c +++ b/drivers/iommu/intel/cache.c @@ -105,12 +105,35 @@ static void cache_tag_unassign(struct dmar_domain *domain, u16 did, spin_unlock_irqrestore(&domain->cache_lock, flags); }
+/* domain->qi_batch will be freed in iommu_free_domain() path. */ +static int domain_qi_batch_alloc(struct dmar_domain *domain) +{ + unsigned long flags; + int ret = 0; + + spin_lock_irqsave(&domain->cache_lock, flags); + if (domain->qi_batch) + goto out_unlock; + + domain->qi_batch = kzalloc(sizeof(*domain->qi_batch), GFP_ATOMIC); + if (!domain->qi_batch) + ret = -ENOMEM; +out_unlock: + spin_unlock_irqrestore(&domain->cache_lock, flags); + + return ret; +} + static int __cache_tag_assign_domain(struct dmar_domain *domain, u16 did, struct device *dev, ioasid_t pasid) { struct device_domain_info *info = dev_iommu_priv_get(dev); int ret;
+ ret = domain_qi_batch_alloc(domain); + if (ret) + return ret; + ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_IOTLB); if (ret || !info->ats_enabled) return ret; @@ -139,6 +162,10 @@ static int __cache_tag_assign_parent_domain(struct dmar_domain *domain, u16 did, struct device_domain_info *info = dev_iommu_priv_get(dev); int ret;
+ ret = domain_qi_batch_alloc(domain); + if (ret) + return ret; + ret = cache_tag_assign(domain, did, dev, pasid, CACHE_TAG_NESTING_IOTLB); if (ret || !info->ats_enabled) return ret; @@ -190,13 +217,6 @@ int cache_tag_assign_domain(struct dmar_domain *domain, u16 did = domain_get_id_for_dev(domain, dev); int ret;
- /* domain->qi_bach will be freed in iommu_free_domain() path. */ - if (!domain->qi_batch) { - domain->qi_batch = kzalloc(sizeof(*domain->qi_batch), GFP_KERNEL); - if (!domain->qi_batch) - return -ENOMEM; - } - ret = __cache_tag_assign_domain(domain, did, dev, pasid); if (ret || domain->domain.type != IOMMU_DOMAIN_NESTED) return ret;