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authorWill Deacon <will@kernel.org>2024-05-02 12:37:23 +0300
committerChristoph Hellwig <hch@lst.de>2024-05-02 15:57:04 +0300
commit75961ffb5cb3e5196f19cae7683f35cc88b50800 (patch)
tree20e179fa900685e7ca35bf5c58e1ce35a95fbf2f /kernel/dma
parente67572cd2204894179d89bd7b984072f19313b03 (diff)
downloadlinux-75961ffb5cb3e5196f19cae7683f35cc88b50800.tar.xz
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: 1aaa736815eb ("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>
Diffstat (limited to 'kernel/dma')
-rw-r--r--kernel/dma/swiotlb.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index a5e0dfc44d24..0de66f0ff43a 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1798,6 +1798,7 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
mem->for_alloc = true;
#ifdef CONFIG_SWIOTLB_DYNAMIC
spin_lock_init(&mem->lock);
+ INIT_LIST_HEAD_RCU(&mem->pools);
#endif
add_mem_pool(mem, pool);