• Qian Cai's avatar
    iommu/amd: fix a crash in iova_magazine_free_pfns · 8cf66504
    Qian Cai authored
    The commit b3aa14f0 ("iommu: remove the mapping_error dma_map_ops
    method") incorrectly changed the checking from dma_ops_alloc_iova() in
    map_sg() causes a crash under memory pressure as dma_ops_alloc_iova()
    never return DMA_MAPPING_ERROR on failure but 0, so the error handling
    is all wrong.
    
       kernel BUG at drivers/iommu/iova.c:801!
        Workqueue: kblockd blk_mq_run_work_fn
        RIP: 0010:iova_magazine_free_pfns+0x7d/0xc0
        Call Trace:
         free_cpu_cached_iovas+0xbd/0x150
         alloc_iova_fast+0x8c/0xba
         dma_ops_alloc_iova.isra.6+0x65/0xa0
         map_sg+0x8c/0x2a0
         scsi_dma_map+0xc6/0x160
         pqi_aio_submit_io+0x1f6/0x440 [smartpqi]
         pqi_scsi_queue_command+0x90c/0xdd0 [smartpqi]
         scsi_queue_rq+0x79c/0x1200
         blk_mq_dispatch_rq_list+0x4dc/0xb70
         blk_mq_sched_dispatch_requests+0x249/0x310
         __blk_mq_run_hw_queue+0x128/0x200
         blk_mq_run_work_fn+0x27/0x30
         process_one_work+0x522/0xa10
         worker_thread+0x63/0x5b0
         kthread+0x1d2/0x1f0
         ret_from_fork+0x22/0x40
    
    Fixes: b3aa14f0 ("iommu: remove the mapping_error dma_map_ops method")
    Signed-off-by: default avatarQian Cai <cai@lca.pw>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    8cf66504
amd_iommu.c 104 KB