From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
iommu@lists.linux-foundation.org, Joerg Roedel <jroedel@suse.de>
Subject: [PATCH AUTOSEL 4.4 14/19] iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr()
Date: Sat, 18 Apr 2020 10:44:31 -0400 [thread overview]
Message-ID: <20200418144436.10818-14-sashal@kernel.org> (raw)
In-Reply-To: <20200418144436.10818-1-sashal@kernel.org>
From: Qian Cai <cai@lca.pw>
[ Upstream commit c6f4ebdeba4cff590594df931ff1ee610c426431 ]
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>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 ed6cb3abf645c..73ac0888d3995 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4164,7 +4164,8 @@ 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;
--
2.20.1
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prev parent reply other threads:[~2020-04-18 14:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-18 14:44 [PATCH AUTOSEL 4.4 01/19] iommu/amd: Fix the configuration of GCR3 table root pointer Sasha Levin
2020-04-18 14:44 ` Sasha Levin [this message]
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