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authorSowmini Varadhan <sowmini.varadhan@oracle.com>2015-09-22 14:59:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-22 15:09:53 -0700
commitd046b770c9fc36ccb19c27afdb8322220108cbc7 (patch)
tree3dca8790fdaa85708c320b6414a4ffbfbd1ec032
parent769a8089c1fd2fe94c13e66fe6e03d7820953ee3 (diff)
downloadlinux-d046b770c9fc36ccb19c27afdb8322220108cbc7.tar.bz2
lib/iommu-common.c: do not try to deref a null iommu->lazy_flush() pointer when n < pool->hint
The check for invoking iommu->lazy_flush() from iommu_tbl_range_alloc() has to be refactored so that we only call ->lazy_flush() if it is non-null. I had a sparc kernel that was crashing when I was trying to process some very large perf.data files- the crash happens when the scsi driver calls into dma_4v_map_sg and thus the iommu_tbl_range_alloc(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: David S. Miller <davem@davemloft.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--lib/iommu-common.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/lib/iommu-common.c b/lib/iommu-common.c
index ff19f66d3f7f..b1c93e94ca7a 100644
--- a/lib/iommu-common.c
+++ b/lib/iommu-common.c
@@ -21,8 +21,7 @@ static DEFINE_PER_CPU(unsigned int, iommu_hash_common);
static inline bool need_flush(struct iommu_map_table *iommu)
{
- return (iommu->lazy_flush != NULL &&
- (iommu->flags & IOMMU_NEED_FLUSH) != 0);
+ return ((iommu->flags & IOMMU_NEED_FLUSH) != 0);
}
static inline void set_flush(struct iommu_map_table *iommu)
@@ -211,7 +210,8 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
goto bail;
}
}
- if (n < pool->hint || need_flush(iommu)) {
+ if (iommu->lazy_flush &&
+ (n < pool->hint || need_flush(iommu))) {
clear_flush(iommu);
iommu->lazy_flush(iommu);
}