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 --- drivers/clk/sprd/common.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 drivers/clk/sprd/common.c (limited to 'drivers/clk/sprd/common.c') diff --git a/drivers/clk/sprd/common.c b/drivers/clk/sprd/common.c new file mode 100644 index 000000000..0f2181617 --- /dev/null +++ b/drivers/clk/sprd/common.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Spreadtrum clock infrastructure +// +// Copyright (C) 2017 Spreadtrum, Inc. +// Author: Chunyan Zhang + +#include +#include +#include +#include +#include + +#include "common.h" + +static const struct regmap_config sprdclk_regmap_config = { + .reg_bits = 32, + .reg_stride = 4, + .val_bits = 32, + .fast_io = true, +}; + +static void sprd_clk_set_regmap(const struct sprd_clk_desc *desc, + struct regmap *regmap) +{ + int i; + struct sprd_clk_common *cclk; + + for (i = 0; i < desc->num_clk_clks; i++) { + cclk = desc->clk_clks[i]; + if (!cclk) + continue; + + cclk->regmap = regmap; + } +} + +int sprd_clk_regmap_init(struct platform_device *pdev, + const struct sprd_clk_desc *desc) +{ + void __iomem *base; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node, *np; + struct regmap *regmap; + struct resource *res; + struct regmap_config reg_config = sprdclk_regmap_config; + + if (of_property_present(node, "sprd,syscon")) { + regmap = syscon_regmap_lookup_by_phandle(node, "sprd,syscon"); + if (IS_ERR(regmap)) { + pr_err("%s: failed to get syscon regmap\n", __func__); + return PTR_ERR(regmap); + } + } else if (of_device_is_compatible(np = of_get_parent(node), "syscon") || + (of_node_put(np), 0)) { + regmap = device_node_to_regmap(np); + of_node_put(np); + if (IS_ERR(regmap)) { + dev_err(dev, "failed to get regmap from its parent.\n"); + return PTR_ERR(regmap); + } + } else { + base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(base)) + return PTR_ERR(base); + + reg_config.max_register = resource_size(res) - reg_config.reg_stride; + + regmap = devm_regmap_init_mmio(&pdev->dev, base, + ®_config); + if (IS_ERR(regmap)) { + pr_err("failed to init regmap\n"); + return PTR_ERR(regmap); + } + } + + sprd_clk_set_regmap(desc, regmap); + + return 0; +} +EXPORT_SYMBOL_GPL(sprd_clk_regmap_init); + +int sprd_clk_probe(struct device *dev, struct clk_hw_onecell_data *clkhw) +{ + int i, ret; + struct clk_hw *hw; + + for (i = 0; i < clkhw->num; i++) { + const char *name; + + hw = clkhw->hws[i]; + if (!hw) + continue; + + name = hw->init->name; + ret = devm_clk_hw_register(dev, hw); + if (ret) { + dev_err(dev, "Couldn't register clock %d - %s\n", + i, name); + return ret; + } + } + + ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clkhw); + if (ret) + dev_err(dev, "Failed to add clock provider\n"); + + return ret; +} +EXPORT_SYMBOL_GPL(sprd_clk_probe); + +MODULE_DESCRIPTION("Spreadtrum clock infrastructure"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1