From 7a6fd9e6726c69f35c5974bd971bb4853458d5c8 Mon Sep 17 00:00:00 2001 From: Lance Richardson Date: Thu, 18 Jul 2024 14:38:24 +0000 Subject: [PATCH] dma: fix call order in dmam_free_coherent BugLink: https://bugs.launchpad.net/bugs/2083196 [ Upstream commit 28e8b7406d3a1f5329a03aa25a43aa28e087cb20 ] dmam_free_coherent() frees a DMA allocation, which makes the freed vaddr available for reuse, then calls devres_destroy() to remove and free the data structure used to track the DMA allocation. Between the two calls, it is possible for a concurrent task to make an allocation with the same vaddr and add it to the devres list. If this happens, there will be two entries in the devres list with the same vaddr and devres_destroy() can free the wrong entry, triggering the WARN_ON() in dmam_match. Fix by destroying the devres entry before freeing the DMA allocation. Tested: kokonut //net/encryption http://sponge2/b9145fe6-0f72-4325-ac2f-a84d81075b03 Fixes: 9ac7849e35f7 ("devres: device resource management") Signed-off-by: Lance Richardson Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin Signed-off-by: Portia Stephens Signed-off-by: Roxana Nicolescu --- kernel/dma/mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 58db8fd70471..89cabc450347 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -67,8 +67,8 @@ void dmam_free_coherent(struct device *dev, size_t size, void *vaddr, { struct dma_devres match_data = { size, vaddr, dma_handle }; - dma_free_coherent(dev, size, vaddr, dma_handle); WARN_ON(devres_destroy(dev, dmam_release, dmam_match, &match_data)); + dma_free_coherent(dev, size, vaddr, dma_handle); } EXPORT_SYMBOL(dmam_free_coherent);