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linux/kernel/dma
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Levi Yun c212d91070 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 20:00:06 +01:00
..
coherent.c dma-mapping: clear dev->dma_mem to NULL after freeing it 2024-01-25 15:35:26 -08:00
contiguous.c Revert "dma-contiguous: check for memory region overlap" 2023-09-08 05:58:32 -03:00
debug.c dma-debug: fix a possible deadlock on radix_lock 2024-12-14 20:00:06 +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: Leak pages on dma_set_decrypted() failure 2024-04-13 13:07:32 +02:00
direct.h dma-mapping: force bouncing if the kmalloc() size is not cache-line-aligned 2023-06-19 16:19:23 -07:00
dummy.c dma-mapping: return error code from dma_dummy_map_sg() 2021-08-09 17:13:06 +02:00
Kconfig dma-contiguous: fix the Kconfig entry for CONFIG_DMA_NUMA_CMA 2023-08-30 13:52:53 +02:00
Makefile dma-mapping: remove CONFIG_DMA_REMAP 2022-03-03 14:00:57 +03:00
map_benchmark.c dma-mapping: benchmark: Don't starve others when doing the test 2024-09-12 11:11:37 +02:00
mapping.c Revert "change alloc_pages name in dma_map_ops to avoid name conflicts" 2024-09-04 13:28:24 +02:00
ops_helpers.c dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable} 2021-07-16 11:30:26 +02:00
pool.c dma-pool: remove a __maybe_unused label in atomic_pool_expand 2023-08-31 14:12:37 +02:00
remap.c dma-remap: use kvmalloc_array/kvfree for larger dma memory remap 2023-06-07 15:06:28 +02:00
swiotlb.c swiotlb: extend buffer pre-padding to alloc_align_mask if necessary 2024-06-21 14:38:46 +02:00