Messages in this thread Patch in this message | | | From | Qian Cai <> | Subject | [PATCH] iommu/vt-d: silence a RCU-list debugging warning | Date | Tue, 17 Mar 2020 11:03:26 -0400 |
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dmar_find_atsr() calls list_for_each_entry_rcu() outside of an RCU read side critical section but with dmar_global_lock held. Silence this false positive.
drivers/iommu/intel-iommu.c:4504 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff9755bee8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1a6/0xe19
Call Trace: dump_stack+0xa4/0xfe lockdep_rcu_suspicious+0xeb/0xf5 dmar_find_atsr+0x1ab/0x1c0 dmar_parse_one_atsr+0x64/0x220 dmar_walk_remapping_entries+0x130/0x380 dmar_table_init+0x166/0x243 intel_iommu_init+0x1ab/0xe19 pci_iommu_init+0x1a/0x44 do_one_initcall+0xae/0x4d0 kernel_init_freeable+0x412/0x4c5 kernel_init+0x19/0x193
Signed-off-by: Qian Cai <cai@lca.pw> --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 4be549478691..ef0a5246700e 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4501,7 +4501,8 @@ static struct dmar_atsr_unit *dmar_find_atsr(struct acpi_dmar_atsr *atsr) struct dmar_atsr_unit *atsru; struct acpi_dmar_atsr *tmp; - list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) { + list_for_each_entry_rcu(atsru, &dmar_atsr_units, list, + dmar_rcu_check()) { tmp = (struct acpi_dmar_atsr *)atsru->hdr; if (atsr->segment != tmp->segment) continue; -- 2.21.0 (Apple Git-122.2)
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