From d5692d4af08cde48ee98968aeb62077e2f6c50d5 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Wed, 12 Jun 2019 08:28:49 +0800 Subject: iommu/vt-d: Fix suspicious RCU usage in probe_acpi_namespace_devices() The drhd and device scope list should be iterated with the iommu global lock held. Otherwise, a suspicious RCU usage message will be displayed. [ 3.695886] ============================= [ 3.695917] WARNING: suspicious RCU usage [ 3.695950] 5.2.0-rc2+ #2467 Not tainted [ 3.695981] ----------------------------- [ 3.696014] drivers/iommu/intel-iommu.c:4569 suspicious rcu_dereference_check() usage! [ 3.696069] other info that might help us debug this: [ 3.696126] rcu_scheduler_active = 2, debug_locks = 1 [ 3.696173] no locks held by swapper/0/1. [ 3.696204] stack backtrace: [ 3.696241] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc2+ #2467 [ 3.696370] Call Trace: [ 3.696404] dump_stack+0x85/0xcb [ 3.696441] intel_iommu_init+0x128c/0x13ce [ 3.696478] ? kmem_cache_free+0x16b/0x2c0 [ 3.696516] ? __fput+0x14b/0x270 [ 3.696550] ? __call_rcu+0xb7/0x300 [ 3.696583] ? get_max_files+0x10/0x10 [ 3.696631] ? set_debug_rodata+0x11/0x11 [ 3.696668] ? e820__memblock_setup+0x60/0x60 [ 3.696704] ? pci_iommu_init+0x16/0x3f [ 3.696737] ? set_debug_rodata+0x11/0x11 [ 3.696770] pci_iommu_init+0x16/0x3f [ 3.696805] do_one_initcall+0x5d/0x2e4 [ 3.696844] ? set_debug_rodata+0x11/0x11 [ 3.696880] ? rcu_read_lock_sched_held+0x6b/0x80 [ 3.696924] kernel_init_freeable+0x1f0/0x27c [ 3.696961] ? rest_init+0x260/0x260 [ 3.696997] kernel_init+0xa/0x110 [ 3.697028] ret_from_fork+0x3a/0x50 Fixes: fa212a97f3a36 ("iommu/vt-d: Probe DMA-capable ACPI name space devices") Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/iommu/intel-iommu.c') diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index c31fbe5790c7..9761ac366e3f 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4821,8 +4821,10 @@ int __init intel_iommu_init(void) cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL, intel_iommu_cpu_dead); + down_read(&dmar_global_lock); if (probe_acpi_namespace_devices()) pr_warn("ACPI name space devices didn't probe correctly\n"); + up_read(&dmar_global_lock); /* Finally, we enable the DMA remapping hardware. */ for_each_iommu(iommu, drhd) { -- cgit v1.2.3-55-g7522