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Will Deacon 75961ffb5c swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y 
Using restricted DMA pools (CONFIG_DMA_RESTRICTED_POOL=y) in conjunction
with dynamic SWIOTLB (CONFIG_SWIOTLB_DYNAMIC=y) leads to the following
crash when initialising the restricted pools at boot-time:

  | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
  | Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
  | pc : rmem_swiotlb_device_init+0xfc/0x1ec
  | lr : rmem_swiotlb_device_init+0xf0/0x1ec
  | Call trace:
  |  rmem_swiotlb_device_init+0xfc/0x1ec
  |  of_reserved_mem_device_init_by_idx+0x18c/0x238
  |  of_dma_configure_id+0x31c/0x33c
  |  platform_dma_configure+0x34/0x80

faddr2line reveals that the crash is in the list validation code:

  include/linux/list.h:83
  include/linux/rculist.h:79
  include/linux/rculist.h:106
  kernel/dma/swiotlb.c:306
  kernel/dma/swiotlb.c:1695

because add_mem_pool() is trying to list_add_rcu() to a NULL
'mem->pools'.

Fix the crash by initialising the 'mem->pools' list_head in
rmem_swiotlb_device_init() before calling add_mem_pool().

Reported-by: Nikita Ioffe <ioffe@google.com>
Tested-by: Nikita Ioffe <ioffe@google.com>
Fixes: 1aaa736815 ("swiotlb: allocate a new memory pool when existing pools are full")
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
 		2024-05-02 14:57:04 +02:00
..
Kconfig dma-direct: add a CONFIG_ARCH_HAS_DMA_ALLOC symbol 2023-10-22 16:38:54 +02:00
Makefile
…
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-mapping fixes for Linux 6.8 2024-01-18 16:49:34 -08:00
debug.h
…
direct.c dma-direct: Leak pages on dma_set_decrypted() failure 2024-02-28 05:31:38 -08:00
direct.h dma-mapping: fix dma_addressing_limited() if dma_range_map can't cover all system RAM 2023-11-06 08:38:16 +01:00
dummy.c
…
map_benchmark.c
…
mapping.c dma-mapping: fix dma_addressing_limited() if dma_range_map can't cover all system RAM 2023-11-06 08:38:16 +01:00
ops_helpers.c
…
pool.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
remap.c
…
swiotlb.c swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y 2024-05-02 14:57:04 +02:00