From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>, David Woodhouse <dwmw2@infradead.org>
Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com,
kevin.tian@intel.com, sai.praneeth.prakhya@intel.com, cai@lca.pw,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH 4/6] iommu/vt-d: Fix suspicious RCU usage in probe_acpi_namespace_devices()
Date: Sun, 9 Jun 2019 10:38:01 +0800 [thread overview]
Message-ID: <20190609023803.23832-5-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20190609023803.23832-1-baolu.lu@linux.intel.com>
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 <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 5251533a18a4..d1cd7e449161 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4793,8 +4793,10 @@ 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) {
--
2.17.1
next prev parent reply other threads:[~2019-06-09 2:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-09 2:37 [PATCH 0/6] iommu/vt-d: Fixes and cleanups for linux-next Lu Baolu
2019-06-09 2:37 ` [PATCH 1/6] iommu/vt-d: Don't return error when device gets right domain Lu Baolu
2019-06-09 2:37 ` [PATCH 2/6] iommu/vt-d: Set domain type for a private domain Lu Baolu
2019-06-09 2:38 ` [PATCH 3/6] iommu/vt-d: Don't enable iommu's which have been ignored Lu Baolu
2019-06-09 2:38 ` Lu Baolu [this message]
2019-06-09 2:38 ` [PATCH 5/6] iommu/vt-d: Cleanup after delegating DMA domain to generic iommu Lu Baolu
2019-06-10 18:45 ` Mehta, Sohil
2019-06-10 19:25 ` Sai Praneeth Prakhya
2019-06-11 5:43 ` Lu Baolu
2019-06-09 2:38 ` [PATCH 6/6] iommu/vt-d: Consolidate domain_init() to avoid duplication Lu Baolu
2019-06-11 16:55 ` [PATCH 0/6] iommu/vt-d: Fixes and cleanups for linux-next Qian Cai
2019-06-11 23:40 ` Lu Baolu
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