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/clk-devres.c | 359 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 359 insertions(+) create mode 100644 drivers/clk/clk-devres.c (limited to 'drivers/clk/clk-devres.c') diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c new file mode 100644 index 000000000..4cc3863bd --- /dev/null +++ b/drivers/clk/clk-devres.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +struct devm_clk_state { + struct clk *clk; + void (*exit)(struct clk *clk); +}; + +static void devm_clk_release(struct device *dev, void *res) +{ + struct devm_clk_state *state = res; + + if (state->exit) + state->exit(state->clk); + + clk_put(state->clk); +} + +static struct clk *__devm_clk_get(struct device *dev, const char *id, + struct clk *(*get)(struct device *dev, const char *id), + int (*init)(struct clk *clk), + void (*exit)(struct clk *clk)) +{ + struct devm_clk_state *state; + struct clk *clk; + int ret; + + state = devres_alloc(devm_clk_release, sizeof(*state), GFP_KERNEL); + if (!state) + return ERR_PTR(-ENOMEM); + + clk = get(dev, id); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + goto err_clk_get; + } + + if (init) { + ret = init(clk); + if (ret) + goto err_clk_init; + } + + state->clk = clk; + state->exit = exit; + + devres_add(dev, state); + + return clk; + +err_clk_init: + + clk_put(clk); +err_clk_get: + + devres_free(state); + return ERR_PTR(ret); +} + +struct clk *devm_clk_get(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get, NULL, NULL); +} +EXPORT_SYMBOL(devm_clk_get); + +struct clk *devm_clk_get_prepared(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get, clk_prepare, clk_unprepare); +} +EXPORT_SYMBOL_GPL(devm_clk_get_prepared); + +struct clk *devm_clk_get_enabled(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get, + clk_prepare_enable, clk_disable_unprepare); +} +EXPORT_SYMBOL_GPL(devm_clk_get_enabled); + +struct clk *devm_clk_get_optional(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get_optional, NULL, NULL); +} +EXPORT_SYMBOL(devm_clk_get_optional); + +struct clk *devm_clk_get_optional_prepared(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get_optional, + clk_prepare, clk_unprepare); +} +EXPORT_SYMBOL_GPL(devm_clk_get_optional_prepared); + +struct clk *devm_clk_get_optional_enabled(struct device *dev, const char *id) +{ + return __devm_clk_get(dev, id, clk_get_optional, + clk_prepare_enable, clk_disable_unprepare); +} +EXPORT_SYMBOL_GPL(devm_clk_get_optional_enabled); + +static void devm_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +struct clk *devm_clk_get_optional_enabled_with_rate(struct device *dev, + const char *id, + unsigned long rate) +{ + struct clk *clk; + int ret; + + clk = devm_clk_get_optional(dev, id); + if (IS_ERR(clk)) + return ERR_CAST(clk); + + ret = clk_set_rate(clk, rate); + if (ret) + goto out_put_clk; + + ret = clk_prepare_enable(clk); + if (ret) + goto out_put_clk; + + ret = devm_add_action_or_reset(dev, devm_clk_disable_unprepare, clk); + if (ret) + goto out_put_clk; + + return clk; + +out_put_clk: + devm_clk_put(dev, clk); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(devm_clk_get_optional_enabled_with_rate); + +struct clk_bulk_devres { + struct clk_bulk_data *clks; + int num_clks; +}; + +static void devm_clk_bulk_release(struct device *dev, void *res) +{ + struct clk_bulk_devres *devres = res; + + clk_bulk_put(devres->num_clks, devres->clks); +} + +static int __devm_clk_bulk_get(struct device *dev, int num_clks, + struct clk_bulk_data *clks, bool optional) +{ + struct clk_bulk_devres *devres; + int ret; + + devres = devres_alloc(devm_clk_bulk_release, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + if (optional) + ret = clk_bulk_get_optional(dev, num_clks, clks); + else + ret = clk_bulk_get(dev, num_clks, clks); + if (!ret) { + devres->clks = clks; + devres->num_clks = num_clks; + devres_add(dev, devres); + } else { + devres_free(devres); + } + + return ret; +} + +int __must_check devm_clk_bulk_get(struct device *dev, int num_clks, + struct clk_bulk_data *clks) +{ + return __devm_clk_bulk_get(dev, num_clks, clks, false); +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get); + +int __must_check devm_clk_bulk_get_optional(struct device *dev, int num_clks, + struct clk_bulk_data *clks) +{ + return __devm_clk_bulk_get(dev, num_clks, clks, true); +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_optional); + +static void devm_clk_bulk_release_enable(struct device *dev, void *res) +{ + struct clk_bulk_devres *devres = res; + + clk_bulk_disable_unprepare(devres->num_clks, devres->clks); + clk_bulk_put(devres->num_clks, devres->clks); +} + +static int __devm_clk_bulk_get_enable(struct device *dev, int num_clks, + struct clk_bulk_data *clks, bool optional) +{ + struct clk_bulk_devres *devres; + int ret; + + devres = devres_alloc(devm_clk_bulk_release_enable, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + if (optional) + ret = clk_bulk_get_optional(dev, num_clks, clks); + else + ret = clk_bulk_get(dev, num_clks, clks); + if (ret) + goto err_clk_get; + + ret = clk_bulk_prepare_enable(num_clks, clks); + if (ret) + goto err_clk_prepare; + + devres->clks = clks; + devres->num_clks = num_clks; + devres_add(dev, devres); + + return 0; + +err_clk_prepare: + clk_bulk_put(num_clks, clks); +err_clk_get: + devres_free(devres); + return ret; +} + +int __must_check devm_clk_bulk_get_enable(struct device *dev, int num_clks, + struct clk_bulk_data *clks) +{ + return __devm_clk_bulk_get_enable(dev, num_clks, clks, false); +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_enable); + +int __must_check devm_clk_bulk_get_optional_enable(struct device *dev, int num_clks, + struct clk_bulk_data *clks) +{ + return __devm_clk_bulk_get_enable(dev, num_clks, clks, true); +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_optional_enable); + +static void devm_clk_bulk_release_all(struct device *dev, void *res) +{ + struct clk_bulk_devres *devres = res; + + clk_bulk_put_all(devres->num_clks, devres->clks); +} + +int __must_check devm_clk_bulk_get_all(struct device *dev, + struct clk_bulk_data **clks) +{ + struct clk_bulk_devres *devres; + int ret; + + devres = devres_alloc(devm_clk_bulk_release_all, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + ret = clk_bulk_get_all(dev, &devres->clks); + if (ret > 0) { + *clks = devres->clks; + devres->num_clks = ret; + devres_add(dev, devres); + } else { + devres_free(devres); + } + + return ret; +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all); + +static void devm_clk_bulk_release_all_enable(struct device *dev, void *res) +{ + struct clk_bulk_devres *devres = res; + + clk_bulk_disable_unprepare(devres->num_clks, devres->clks); + clk_bulk_put_all(devres->num_clks, devres->clks); +} + +int __must_check devm_clk_bulk_get_all_enabled(struct device *dev, + struct clk_bulk_data **clks) +{ + struct clk_bulk_devres *devres; + int ret; + + devres = devres_alloc(devm_clk_bulk_release_all_enable, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + ret = clk_bulk_get_all(dev, &devres->clks); + if (ret > 0) { + *clks = devres->clks; + devres->num_clks = ret; + } else { + devres_free(devres); + return ret; + } + + ret = clk_bulk_prepare_enable(devres->num_clks, *clks); + if (!ret) { + devres_add(dev, devres); + } else { + clk_bulk_put_all(devres->num_clks, devres->clks); + devres_free(devres); + return ret; + } + + return devres->num_clks; +} +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all_enabled); + +static int devm_clk_match(struct device *dev, void *res, void *data) +{ + struct clk **c = res; + if (!c || !*c) { + WARN_ON(!c || !*c); + return 0; + } + return *c == data; +} + +void devm_clk_put(struct device *dev, struct clk *clk) +{ + int ret; + + ret = devres_release(dev, devm_clk_release, devm_clk_match, clk); + + WARN_ON(ret); +} +EXPORT_SYMBOL(devm_clk_put); + +struct clk *devm_get_clk_from_child(struct device *dev, + struct device_node *np, const char *con_id) +{ + struct devm_clk_state *state; + struct clk *clk; + + state = devres_alloc(devm_clk_release, sizeof(*state), GFP_KERNEL); + if (!state) + return ERR_PTR(-ENOMEM); + + clk = of_clk_get_by_name(np, con_id); + if (!IS_ERR(clk)) { + state->clk = clk; + devres_add(dev, state); + } else { + devres_free(state); + } + + return clk; +} +EXPORT_SYMBOL(devm_get_clk_from_child); -- cgit v1.3.1