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 --- arch/x86/hyperv/nested.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 arch/x86/hyperv/nested.c (limited to 'arch/x86/hyperv/nested.c') diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c new file mode 100644 index 000000000..8ccbb7c4f --- /dev/null +++ b/arch/x86/hyperv/nested.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Hyper-V nested virtualization code. + * + * Copyright (C) 2018, Microsoft, Inc. + * + * Author : Lan Tianyu + */ +#define pr_fmt(fmt) "Hyper-V: " fmt + + +#include +#include +#include +#include +#include + +#include + +int hyperv_flush_guest_mapping(u64 as) +{ + struct hv_guest_mapping_flush *flush; + u64 status; + unsigned long flags; + int ret = -ENOTSUPP; + + if (!hv_hypercall_pg) + goto fault; + + local_irq_save(flags); + + flush = *this_cpu_ptr(hyperv_pcpu_input_arg); + + if (unlikely(!flush)) { + local_irq_restore(flags); + goto fault; + } + + flush->address_space = as; + flush->flags = 0; + + status = hv_do_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE, + flush, NULL); + local_irq_restore(flags); + + if (hv_result_success(status)) + ret = 0; + +fault: + trace_hyperv_nested_flush_guest_mapping(as, ret); + return ret; +} +EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping); + +int hyperv_fill_flush_guest_mapping_list( + struct hv_guest_mapping_flush_list *flush, + u64 start_gfn, u64 pages) +{ + u64 cur = start_gfn; + u64 additional_pages; + int gpa_n = 0; + + do { + /* + * If flush requests exceed max flush count, go back to + * flush tlbs without range. + */ + if (gpa_n >= HV_MAX_FLUSH_REP_COUNT) + return -ENOSPC; + + additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1; + + flush->gpa_list[gpa_n].page.additional_pages = additional_pages; + flush->gpa_list[gpa_n].page.largepage = false; + flush->gpa_list[gpa_n].page.basepfn = cur; + + pages -= additional_pages + 1; + cur += additional_pages + 1; + gpa_n++; + } while (pages > 0); + + return gpa_n; +} +EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list); + +int hyperv_flush_guest_mapping_range(u64 as, + hyperv_fill_flush_list_func fill_flush_list_func, void *data) +{ + struct hv_guest_mapping_flush_list *flush; + u64 status; + unsigned long flags; + int ret = -ENOTSUPP; + int gpa_n = 0; + + if (!hv_hypercall_pg || !fill_flush_list_func) + goto fault; + + local_irq_save(flags); + + flush = *this_cpu_ptr(hyperv_pcpu_input_arg); + + if (unlikely(!flush)) { + local_irq_restore(flags); + goto fault; + } + + flush->address_space = as; + flush->flags = 0; + + gpa_n = fill_flush_list_func(flush, data); + if (gpa_n < 0) { + local_irq_restore(flags); + goto fault; + } + + status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST, + gpa_n, 0, flush, NULL); + + local_irq_restore(flags); + + if (hv_result_success(status)) + ret = 0; + else + ret = hv_result(status); +fault: + trace_hyperv_nested_flush_guest_mapping_range(as, ret); + return ret; +} +EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range); -- cgit v1.3.1