From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- lib/devres.c | 399 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 399 insertions(+) create mode 100644 lib/devres.c (limited to 'lib/devres.c') diff --git a/lib/devres.c b/lib/devres.c new file mode 100644 index 000000000..378b07730 --- /dev/null +++ b/lib/devres.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum devm_ioremap_type { + DEVM_IOREMAP = 0, + DEVM_IOREMAP_UC, + DEVM_IOREMAP_WC, + DEVM_IOREMAP_NP, +}; + +void devm_ioremap_release(struct device *dev, void *res) +{ + iounmap(*(void __iomem **)res); +} + +static int devm_ioremap_match(struct device *dev, void *res, void *match_data) +{ + return *(void **)res == match_data; +} + +static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset, + resource_size_t size, + enum devm_ioremap_type type) +{ + void __iomem **ptr, *addr = NULL; + + ptr = devres_alloc_node(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL, + dev_to_node(dev)); + if (!ptr) + return NULL; + + switch (type) { + case DEVM_IOREMAP: + addr = ioremap(offset, size); + break; + case DEVM_IOREMAP_UC: + addr = ioremap_uc(offset, size); + break; + case DEVM_IOREMAP_WC: + addr = ioremap_wc(offset, size); + break; + case DEVM_IOREMAP_NP: + addr = ioremap_np(offset, size); + break; + } + + if (addr) { + *ptr = addr; + devres_add(dev, ptr); + } else + devres_free(ptr); + + return addr; +} + +/** + * devm_ioremap - Managed ioremap() + * @dev: Generic device to remap IO address for + * @offset: Resource address to map + * @size: Size of map + * + * Managed ioremap(). Map is automatically unmapped on driver detach. + */ +void __iomem *devm_ioremap(struct device *dev, resource_size_t offset, + resource_size_t size) +{ + return __devm_ioremap(dev, offset, size, DEVM_IOREMAP); +} +EXPORT_SYMBOL(devm_ioremap); + +/** + * devm_ioremap_uc - Managed ioremap_uc() + * @dev: Generic device to remap IO address for + * @offset: Resource address to map + * @size: Size of map + * + * Managed ioremap_uc(). Map is automatically unmapped on driver detach. + */ +void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset, + resource_size_t size) +{ + return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_UC); +} +EXPORT_SYMBOL_GPL(devm_ioremap_uc); + +/** + * devm_ioremap_wc - Managed ioremap_wc() + * @dev: Generic device to remap IO address for + * @offset: Resource address to map + * @size: Size of map + * + * Managed ioremap_wc(). Map is automatically unmapped on driver detach. + */ +void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset, + resource_size_t size) +{ + return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_WC); +} +EXPORT_SYMBOL(devm_ioremap_wc); + +/** + * devm_iounmap - Managed iounmap() + * @dev: Generic device to unmap for + * @addr: Address to unmap + * + * Managed iounmap(). @addr must have been mapped using devm_ioremap*(). + */ +void devm_iounmap(struct device *dev, void __iomem *addr) +{ + WARN_ON(devres_release(dev, devm_ioremap_release, devm_ioremap_match, + (__force void *)addr)); +} +EXPORT_SYMBOL(devm_iounmap); + +static void __iomem * +__devm_ioremap_resource(struct device *dev, const struct resource *res, + enum devm_ioremap_type type) +{ + resource_size_t size; + void __iomem *dest_ptr; + char *pretty_name; + int ret; + + BUG_ON(!dev); + + if (!res || resource_type(res) != IORESOURCE_MEM) { + ret = dev_err_probe(dev, -EINVAL, "invalid resource %pR\n", res); + return IOMEM_ERR_PTR(ret); + } + + if (type == DEVM_IOREMAP && res->flags & IORESOURCE_MEM_NONPOSTED) + type = DEVM_IOREMAP_NP; + + size = resource_size(res); + + if (res->name) + pretty_name = devm_kasprintf(dev, GFP_KERNEL, "%s %s", + dev_name(dev), res->name); + else + pretty_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL); + if (!pretty_name) { + ret = dev_err_probe(dev, -ENOMEM, "can't generate pretty name for resource %pR\n", res); + return IOMEM_ERR_PTR(ret); + } + + if (!devm_request_mem_region(dev, res->start, size, pretty_name)) { + ret = dev_err_probe(dev, -EBUSY, "can't request region for resource %pR\n", res); + return IOMEM_ERR_PTR(ret); + } + + dest_ptr = __devm_ioremap(dev, res->start, size, type); + if (!dest_ptr) { + devm_release_mem_region(dev, res->start, size); + ret = dev_err_probe(dev, -ENOMEM, "ioremap failed for resource %pR\n", res); + return IOMEM_ERR_PTR(ret); + } + + return dest_ptr; +} + +/** + * devm_ioremap_resource() - check, request region, and ioremap resource + * @dev: generic device to handle the resource for + * @res: resource to be handled + * + * Checks that a resource is a valid memory region, requests the memory + * region and ioremaps it. All operations are managed and will be undone + * on driver detach. + * + * Usage example: + * + * res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + * base = devm_ioremap_resource(&pdev->dev, res); + * if (IS_ERR(base)) + * return PTR_ERR(base); + * + * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code + * on failure. + */ +void __iomem *devm_ioremap_resource(struct device *dev, + const struct resource *res) +{ + return __devm_ioremap_resource(dev, res, DEVM_IOREMAP); +} +EXPORT_SYMBOL(devm_ioremap_resource); + +/** + * devm_ioremap_resource_wc() - write-combined variant of + * devm_ioremap_resource() + * @dev: generic device to handle the resource for + * @res: resource to be handled + * + * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code + * on failure. + */ +void __iomem *devm_ioremap_resource_wc(struct device *dev, + const struct resource *res) +{ + return __devm_ioremap_resource(dev, res, DEVM_IOREMAP_WC); +} +EXPORT_SYMBOL(devm_ioremap_resource_wc); + +/* + * devm_of_iomap - Requests a resource and maps the memory mapped IO + * for a given device_node managed by a given device + * + * Checks that a resource is a valid memory region, requests the memory + * region and ioremaps it. All operations are managed and will be undone + * on driver detach of the device. + * + * This is to be used when a device requests/maps resources described + * by other device tree nodes (children or otherwise). + * + * @dev: The device "managing" the resource + * @node: The device-tree node where the resource resides + * @index: index of the MMIO range in the "reg" property + * @size: Returns the size of the resource (pass NULL if not needed) + * + * Usage example: + * + * base = devm_of_iomap(&pdev->dev, node, 0, NULL); + * if (IS_ERR(base)) + * return PTR_ERR(base); + * + * Please Note: This is not a one-to-one replacement for of_iomap() because the + * of_iomap() function does not track whether the region is already mapped. If + * two drivers try to map the same memory, the of_iomap() function will succeed + * but the devm_of_iomap() function will return -EBUSY. + * + * Return: a pointer to the requested and mapped memory or an ERR_PTR() encoded + * error code on failure. + */ +void __iomem *devm_of_iomap(struct device *dev, struct device_node *node, int index, + resource_size_t *size) +{ + struct resource res; + + if (of_address_to_resource(node, index, &res)) + return IOMEM_ERR_PTR(-EINVAL); + if (size) + *size = resource_size(&res); + return devm_ioremap_resource(dev, &res); +} +EXPORT_SYMBOL(devm_of_iomap); + +#ifdef CONFIG_HAS_IOPORT_MAP +/* + * Generic iomap devres + */ +static void devm_ioport_map_release(struct device *dev, void *res) +{ + ioport_unmap(*(void __iomem **)res); +} + +static int devm_ioport_map_match(struct device *dev, void *res, + void *match_data) +{ + return *(void **)res == match_data; +} + +/** + * devm_ioport_map - Managed ioport_map() + * @dev: Generic device to map ioport for + * @port: Port to map + * @nr: Number of ports to map + * + * Managed ioport_map(). Map is automatically unmapped on driver + * detach. + * + * Return: a pointer to the remapped memory or NULL on failure. + */ +void __iomem *devm_ioport_map(struct device *dev, unsigned long port, + unsigned int nr) +{ + void __iomem **ptr, *addr; + + ptr = devres_alloc_node(devm_ioport_map_release, sizeof(*ptr), GFP_KERNEL, + dev_to_node(dev)); + if (!ptr) + return NULL; + + addr = ioport_map(port, nr); + if (addr) { + *ptr = addr; + devres_add(dev, ptr); + } else + devres_free(ptr); + + return addr; +} +EXPORT_SYMBOL(devm_ioport_map); + +/** + * devm_ioport_unmap - Managed ioport_unmap() + * @dev: Generic device to unmap for + * @addr: Address to unmap + * + * Managed ioport_unmap(). @addr must have been mapped using + * devm_ioport_map(). + */ +void devm_ioport_unmap(struct device *dev, void __iomem *addr) +{ + WARN_ON(devres_release(dev, devm_ioport_map_release, + devm_ioport_map_match, (__force void *)addr)); +} +EXPORT_SYMBOL(devm_ioport_unmap); +#endif /* CONFIG_HAS_IOPORT_MAP */ + +static void devm_arch_phys_ac_add_release(struct device *dev, void *res) +{ + arch_phys_wc_del(*((int *)res)); +} + +/** + * devm_arch_phys_wc_add - Managed arch_phys_wc_add() + * @dev: Managed device + * @base: Memory base address + * @size: Size of memory range + * + * Adds a WC MTRR using arch_phys_wc_add() and sets up a release callback. + * See arch_phys_wc_add() for more information. + */ +int devm_arch_phys_wc_add(struct device *dev, unsigned long base, unsigned long size) +{ + int *mtrr; + int ret; + + mtrr = devres_alloc_node(devm_arch_phys_ac_add_release, sizeof(*mtrr), GFP_KERNEL, + dev_to_node(dev)); + if (!mtrr) + return -ENOMEM; + + ret = arch_phys_wc_add(base, size); + if (ret < 0) { + devres_free(mtrr); + return ret; + } + + *mtrr = ret; + devres_add(dev, mtrr); + + return ret; +} +EXPORT_SYMBOL(devm_arch_phys_wc_add); + +struct arch_io_reserve_memtype_wc_devres { + resource_size_t start; + resource_size_t size; +}; + +static void devm_arch_io_free_memtype_wc_release(struct device *dev, void *res) +{ + const struct arch_io_reserve_memtype_wc_devres *this = res; + + arch_io_free_memtype_wc(this->start, this->size); +} + +/** + * devm_arch_io_reserve_memtype_wc - Managed arch_io_reserve_memtype_wc() + * @dev: Managed device + * @start: Memory base address + * @size: Size of memory range + * + * Reserves a memory range with WC caching using arch_io_reserve_memtype_wc() + * and sets up a release callback See arch_io_reserve_memtype_wc() for more + * information. + */ +int devm_arch_io_reserve_memtype_wc(struct device *dev, resource_size_t start, + resource_size_t size) +{ + struct arch_io_reserve_memtype_wc_devres *dr; + int ret; + + dr = devres_alloc_node(devm_arch_io_free_memtype_wc_release, sizeof(*dr), GFP_KERNEL, + dev_to_node(dev)); + if (!dr) + return -ENOMEM; + + ret = arch_io_reserve_memtype_wc(start, size); + if (ret < 0) { + devres_free(dr); + return ret; + } + + dr->start = start; + dr->size = size; + devres_add(dev, dr); + + return ret; +} +EXPORT_SYMBOL(devm_arch_io_reserve_memtype_wc); -- cgit v1.3.1