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 --- tools/testing/vma/shared.c | 123 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 tools/testing/vma/shared.c (limited to 'tools/testing/vma/shared.c') diff --git a/tools/testing/vma/shared.c b/tools/testing/vma/shared.c new file mode 100644 index 000000000..4a39c9d50 --- /dev/null +++ b/tools/testing/vma/shared.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include "shared.h" + + +bool fail_prealloc; +unsigned long mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR; +unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR; +unsigned long stack_guard_gap = 256UL<vm_start = start; + vma->vm_end = end; + vma_set_pgoff(vma, pgoff); + vma_set_anon_pgoff(vma, start >> PAGE_SHIFT); + vma->flags = vma_flags; + vma_assert_detached(vma); + + return vma; +} + +void detach_free_vma(struct vm_area_struct *vma) +{ + vma_mark_detached(vma); + vm_area_free(vma); +} + +struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm, + unsigned long start, unsigned long end, + pgoff_t pgoff, vma_flags_t vma_flags) +{ + struct vm_area_struct *vma = alloc_vma(mm, start, end, pgoff, vma_flags); + + if (vma == NULL) + return NULL; + + if (attach_vma(mm, vma)) { + detach_free_vma(vma); + return NULL; + } + + /* + * Reset this counter which we use to track whether writes have + * begun. Linking to the tree will have caused this to be incremented, + * which means we will get a false positive otherwise. + */ + vma->vm_lock_seq = UINT_MAX; + + return vma; +} + +void reset_dummy_anon_vma(void) +{ + dummy_anon_vma.was_cloned = false; + dummy_anon_vma.was_unlinked = false; +} + +int cleanup_mm(struct mm_struct *mm, struct vma_iterator *vmi) +{ + struct vm_area_struct *vma; + int count = 0; + + fail_prealloc = false; + reset_dummy_anon_vma(); + + vma_iter_set(vmi, 0); + for_each_vma(*vmi, vma) { + detach_free_vma(vma); + count++; + } + + mtree_destroy(&mm->mm_mt); + mm->map_count = 0; + return count; +} + +bool vma_write_started(struct vm_area_struct *vma) +{ + int seq = vma->vm_lock_seq; + + /* We reset after each check. */ + vma->vm_lock_seq = UINT_MAX; + + /* The vma_start_write() stub simply increments this value. */ + return seq > -1; +} + +void __vma_set_dummy_anon_vma(struct vm_area_struct *vma, + struct anon_vma_chain *avc, struct anon_vma *anon_vma) +{ + vma->anon_vma = anon_vma; + INIT_LIST_HEAD(&vma->anon_vma_chain); + list_add(&avc->same_vma, &vma->anon_vma_chain); + avc->anon_vma = vma->anon_vma; +} + +void vma_set_dummy_anon_vma(struct vm_area_struct *vma, + struct anon_vma_chain *avc) +{ + __vma_set_dummy_anon_vma(vma, avc, &dummy_anon_vma); +} + +struct task_struct *get_current(void) +{ + return &__current; +} + +unsigned long rlimit(unsigned int limit) +{ + return (unsigned long)-1; +} -- cgit v1.3.1