From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- io_uring/memmap.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 io_uring/memmap.h (limited to 'io_uring/memmap.h') diff --git a/io_uring/memmap.h b/io_uring/memmap.h new file mode 100644 index 000000000..f4cfbb6b9 --- /dev/null +++ b/io_uring/memmap.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef IO_URING_MEMMAP_H +#define IO_URING_MEMMAP_H + +#define IORING_MAP_OFF_PARAM_REGION 0x20000000ULL +#define IORING_MAP_OFF_ZCRX_REGION 0x30000000ULL + +#define IORING_OFF_ZCRX_SHIFT 16 + +struct page **io_pin_pages(unsigned long uaddr, unsigned long len, int *npages); + +#ifndef CONFIG_MMU +unsigned int io_uring_nommu_mmap_capabilities(struct file *file); +#endif +unsigned long io_uring_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags); +int io_uring_mmap(struct file *file, struct vm_area_struct *vma); + +void io_free_region(struct user_struct *user, struct io_mapped_region *mr); +int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, + struct io_uring_region_desc *reg, + unsigned long mmap_offset); + +static inline void *io_region_get_ptr(struct io_mapped_region *mr) +{ + return mr->ptr; +} + +static inline bool io_region_is_set(struct io_mapped_region *mr) +{ + return !!mr->nr_pages; +} + +static inline void io_region_publish(struct io_ring_ctx *ctx, + struct io_mapped_region *src_region, + struct io_mapped_region *dst_region) +{ + /* + * Once published mmap can find it without holding only the ->mmap_lock + * and not ->uring_lock. + */ + guard(mutex)(&ctx->mmap_lock); + *dst_region = *src_region; +} + +static inline size_t io_region_size(struct io_mapped_region *mr) +{ + return (size_t) mr->nr_pages << PAGE_SHIFT; +} + +#endif -- cgit v1.3.1