From 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 2 Sep 2026 15:31:14 -0700 Subject: treewide: refresh kmalloc_obj() conversions This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook --- samples/kprobes/kprobe_example.c | 129 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 samples/kprobes/kprobe_example.c (limited to 'samples/kprobes/kprobe_example.c') diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c new file mode 100644 index 000000000..53ec6c8b8 --- /dev/null +++ b/samples/kprobes/kprobe_example.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Here's a sample kernel module showing the use of kprobes to dump a + * stack trace and selected registers when kernel_clone() is called. + * + * For more information on theory of operation of kprobes, see + * Documentation/trace/kprobes.rst + * + * You will see the trace data in /var/log/messages and on the console + * whenever kernel_clone() is invoked to create a new process. + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include +#include +#include + +static char symbol[KSYM_NAME_LEN] = "kernel_clone"; +module_param_string(symbol, symbol, KSYM_NAME_LEN, 0644); + +/* For each probe you need to allocate a kprobe structure */ +static struct kprobe kp = { + .symbol_name = symbol, +}; + +/* kprobe pre_handler: called just before the probed instruction is executed */ +static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs) +{ +#ifdef CONFIG_X86 + pr_info("<%s> p->addr = 0x%p, ip = %lx, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->ip, regs->flags); +#endif +#ifdef CONFIG_PPC + pr_info("<%s> p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n", + p->symbol_name, p->addr, regs->nip, regs->msr); +#endif +#ifdef CONFIG_MIPS + pr_info("<%s> p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n", + p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status); +#endif +#ifdef CONFIG_ARM64 + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, pstate = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate); +#endif +#ifdef CONFIG_ARM + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->ARM_pc, (long)regs->ARM_cpsr); +#endif +#ifdef CONFIG_RISCV + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n", + p->symbol_name, p->addr, regs->epc, regs->status); +#endif +#ifdef CONFIG_S390 + pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->psw.addr, regs->flags); +#endif +#ifdef CONFIG_LOONGARCH + pr_info("<%s> p->addr = 0x%p, era = 0x%lx, estat = 0x%lx\n", + p->symbol_name, p->addr, regs->csr_era, regs->csr_estat); +#endif + + /* A dump_stack() here will give a stack backtrace */ + return 0; +} + +/* kprobe post_handler: called after the probed instruction is executed */ +static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs, + unsigned long flags) +{ +#ifdef CONFIG_X86 + pr_info("<%s> p->addr = 0x%p, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->flags); +#endif +#ifdef CONFIG_PPC + pr_info("<%s> p->addr = 0x%p, msr = 0x%lx\n", + p->symbol_name, p->addr, regs->msr); +#endif +#ifdef CONFIG_MIPS + pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n", + p->symbol_name, p->addr, regs->cp0_status); +#endif +#ifdef CONFIG_ARM64 + pr_info("<%s> p->addr = 0x%p, pstate = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->pstate); +#endif +#ifdef CONFIG_ARM + pr_info("<%s> p->addr = 0x%p, cpsr = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->ARM_cpsr); +#endif +#ifdef CONFIG_RISCV + pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n", + p->symbol_name, p->addr, regs->status); +#endif +#ifdef CONFIG_S390 + pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->flags); +#endif +#ifdef CONFIG_LOONGARCH + pr_info("<%s> p->addr = 0x%p, estat = 0x%lx\n", + p->symbol_name, p->addr, regs->csr_estat); +#endif +} + +static int __init kprobe_init(void) +{ + int ret; + kp.pre_handler = handler_pre; + kp.post_handler = handler_post; + + ret = register_kprobe(&kp); + if (ret < 0) { + pr_err("register_kprobe failed, returned %d\n", ret); + return ret; + } + pr_info("Planted kprobe at %p\n", kp.addr); + return 0; +} + +static void __exit kprobe_exit(void) +{ + unregister_kprobe(&kp); + pr_info("kprobe at %p unregistered\n", kp.addr); +} + +module_init(kprobe_init) +module_exit(kprobe_exit) +MODULE_DESCRIPTION("sample kernel module showing the use of kprobes"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1