From 02d715b4a8182f4887d82df82a7b83aced647760 Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Sun, 23 Feb 2020 22:25:39 +0530 Subject: iommu/vt-d: Fix RCU list debugging warnings dmar_drhd_units is traversed using list_for_each_entry_rcu() outside of an RCU read side critical section but under the protection of dmar_global_lock. Hence add corresponding lockdep expression to silence the following false-positive warnings: [ 1.603975] ============================= [ 1.603976] WARNING: suspicious RCU usage [ 1.603977] 5.5.4-stable #17 Not tainted [ 1.603978] ----------------------------- [ 1.603980] drivers/iommu/intel-iommu.c:4769 RCU-list traversed in non-reader section!! [ 1.603869] ============================= [ 1.603870] WARNING: suspicious RCU usage [ 1.603872] 5.5.4-stable #17 Not tainted [ 1.603874] ----------------------------- [ 1.603875] drivers/iommu/dmar.c:293 RCU-list traversed in non-reader section!! Tested-by: Madhuparna Bhowmik Signed-off-by: Amol Grover Cc: stable@vger.kernel.org Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- include/linux/dmar.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/linux/dmar.h') diff --git a/include/linux/dmar.h b/include/linux/dmar.h index f64ca27dc210..712be8bc6a7c 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -69,8 +69,9 @@ struct dmar_pci_notify_info { extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; -#define for_each_drhd_unit(drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) +#define for_each_drhd_unit(drhd) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) #define for_each_active_drhd_unit(drhd) \ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ @@ -81,7 +82,8 @@ extern struct list_head dmar_drhd_units; if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, 0) {} else static inline bool dmar_rcu_check(void) -- cgit v1.2.3 From f5152416528c2295f35dd9c9bd4fb27c4032413d Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Thu, 5 Mar 2020 15:15:02 -0500 Subject: iommu/vt-d: Silence RCU-list debugging warnings Similar to the commit 02d715b4a818 ("iommu/vt-d: Fix RCU list debugging warnings"), there are several other places that call list_for_each_entry_rcu() outside of an RCU read side critical section but with dmar_global_lock held. Silence those false positives as well. drivers/iommu/intel-iommu.c:4288 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1ad/0xb97 drivers/iommu/dmar.c:366 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x125/0xb97 drivers/iommu/intel-iommu.c:5057 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffffa71892c8 (dmar_global_lock){++++}, at: intel_iommu_init+0x61a/0xb13 Signed-off-by: Qian Cai Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/dmar.c | 3 ++- include/linux/dmar.h | 6 ++++-- 2 files changed, 6 insertions(+), 3 deletions(-) (limited to 'include/linux/dmar.h') diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index 071bb42bbbc5..7b16c4db40b4 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -363,7 +363,8 @@ dmar_find_dmaru(struct acpi_dmar_hardware_unit *drhd) { struct dmar_drhd_unit *dmaru; - list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list) + list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list, + dmar_rcu_check()) if (dmaru->segment == drhd->segment && dmaru->reg_base_addr == drhd->address) return dmaru; diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 712be8bc6a7c..d7bf029df737 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -74,11 +74,13 @@ extern struct list_head dmar_drhd_units; dmar_rcu_check()) #define for_each_active_drhd_unit(drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (drhd->ignored) {} else #define for_each_active_iommu(i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ -- cgit v1.2.3