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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-01-05 02:13:31 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-01-05 15:10:52 +0100 |
| commit | 696c7f8e0373026e8bfb29b2d9ff2d0a92059d4d (patch) | |
| tree | b933c78b92d1887fdb28dc7be93af426053da036 /drivers | |
| parent | 0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff) | |
| download | linux-696c7f8e0373026e8bfb29b2d9ff2d0a92059d4d.tar.gz | |
ACPI / DMAR: Avoid passing NULL to acpi_put_table()
Linus reported that commit 174cc7187e6f "ACPICA: Tables: Back port
acpi_get_table_with_size() and early_acpi_os_unmap_memory() from
Linux kernel" added a new warning on his desktop system:
ACPI Warning: Table ffffffff9fe6c0a0, Validation count is zero before decrement
which turns out to come from the acpi_put_table() in
detect_intel_iommu().
This happens if the DMAR table is not present in which case NULL is
passed to acpi_put_table() which doesn't check against that and
attempts to handle it regardless.
For this reason, check the pointer passed to acpi_put_table()
before invoking it.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Fixes: 6b11d1d67713 ("ACPI / osl: Remove acpi_get_table_with_size()/early_acpi_os_unmap_memory() users")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iommu/dmar.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index a88576d50740..8ccbd7023194 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -903,8 +903,10 @@ int __init detect_intel_iommu(void) x86_init.iommu.iommu_init = intel_iommu_init; #endif - acpi_put_table(dmar_tbl); - dmar_tbl = NULL; + if (dmar_tbl) { + acpi_put_table(dmar_tbl); + dmar_tbl = NULL; + } up_write(&dmar_global_lock); return ret ? 1 : -ENODEV; |