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linux/kernel/dma
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Levi Yun f2b95248a1 dma-debug: fix a possible deadlock on radix_lock 
[ Upstream commit 7543c3e3b9 ]

radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock
otherwise, there's a possible deadlock scenario when
dma debug API is called holding rq_lock():

CPU0                   CPU1                       CPU2
dma_free_attrs()
check_unmap()          add_dma_entry()            __schedule() //out
                                                  (A) rq_lock()
get_hash_bucket()
(A) dma_entry_hash
                                                  check_sync()
                       (A) radix_lock()           (W) dma_entry_hash
dma_entry_free()
(W) radix_lock()
                       // CPU2's one
                       (W) rq_lock()

CPU1 situation can happen when it extending radix tree and
it tries to wake up kswapd via wake_all_kswapd().

CPU2 situation can happen while perf_event_task_sched_out()
(i.e. dma sync operation is called while deleting perf_event using
 etm and etr tmc which are Arm Coresight hwtracing driver backends).

To remove this possible situation, call dma_entry_free() after
put_hash_bucket() in check_unmap().

Reported-by: Denis Nikitin <denik@chromium.org>
Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/2WMS7BBSF5OZYB63VT44U5YWLFP5HL6U/#RWM6MLQX5ANBTEQ2PRM7OXCBGCE6NPWU
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-12-14 20:03:52 +01:00
..
coherent.c dma-mapping: clear dev->dma_mem to NULL after freeing it 2023-12-15 12:32:45 +01:00
contiguous.c mm/cma: drop CONFIG_CMA_DEBUG 2024-02-22 10:24:53 -08:00
debug.c dma-debug: fix a possible deadlock on radix_lock 2024-12-14 20:03:52 +01:00
debug.h dma-debug: teach add_dma_entry() about DMA_ATTR_SKIP_CPU_SYNC 2021-10-18 12:46:45 +02:00
direct.c dma-direct: optimize page freeing when it is not addressable 2024-09-04 07:08:51 +03:00
direct.h swiotlb: reduce swiotlb pool lookups 2024-07-10 07:59:03 +02:00
dummy.c dma-mapping: call ->unmap_page and ->unmap_sg unconditionally 2024-08-22 06:18:11 +02:00
Kconfig dma-mapping: clearly mark DMA ops as an architecture feature 2024-09-04 07:08:51 +03:00
Makefile dma-mapping: clearly mark DMA ops as an architecture feature 2024-09-04 07:08:51 +03:00
map_benchmark.c dma-mapping: benchmark: Don't starve others when doing the test 2024-07-09 07:48:32 +02:00
mapping.c dma-mapping: report unlimited DMA addressing in IOMMU DMA path 2024-09-23 08:38:56 +02:00
ops_helpers.c dma-mapping: use IOMMU DMA calls for common alloc/free page calls 2024-09-05 14:29:42 +03:00
pool.c dma-mapping: replace zone_dma_bits by zone_dma_limit 2024-08-22 06:18:00 +02:00
remap.c dma-mapping: use bit masking to check VM_DMA_COHERENT 2024-08-22 06:15:35 +02:00
swiotlb.c dma-mapping: replace zone_dma_bits by zone_dma_limit 2024-08-22 06:18:00 +02:00