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| author | Sowmini Varadhan <sowmini.varadhan@oracle.com> | 2015-09-22 14:59:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-22 15:09:53 -0700 |
| commit | d046b770c9fc36ccb19c27afdb8322220108cbc7 (patch) | |
| tree | 3dca8790fdaa85708c320b6414a4ffbfbd1ec032 | |
| parent | 769a8089c1fd2fe94c13e66fe6e03d7820953ee3 (diff) | |
| download | lwn-d046b770c9fc36ccb19c27afdb8322220108cbc7.tar.gz lwn-d046b770c9fc36ccb19c27afdb8322220108cbc7.zip | |
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.c | 6 |
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); } |