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-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCXz5bNAAKCRCRxhvAZXjc opfjAP9R/J72yxdd2CLGNZ96hyiRX1NgFDOVUhscOvujYJf8ZwD+OoLmKMvAyFW6 hnMhT1n9Q+aq194hyzChOLQaBTejBQ8= =4WCX -----END PGP SIGNATURE----- Merge tag 'kernel-clone-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull kernel_clone() updates from Christian Brauner: "During the v5.9 merge window we reworked the process creation codepaths across multiple architectures. After this work we were only left with the _do_fork() helper based on the struct kernel_clone_args calling convention. As was pointed out _do_fork() isn't valid kernelese especially for a helper that isn't just static. This series removes the _do_fork() helper and introduces the new kernel_clone() helper. The process creation cleanup didn't change the name to something more reasonable mainly because _do_fork() was used in quite a few places. So sending this as a separate series seemed the better strategy. I originally intended to send this early in the v5.9 development cycle after the merge window had closed but given that this was touching quite a few places I decided to defer this until the v5.10 merge window" * tag 'kernel-clone-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: sched: remove _do_fork() tracing: switch to kernel_clone() kgdbts: switch to kernel_clone() kprobes: switch to kernel_clone() x86: switch to kernel_clone() sparc: switch to kernel_clone() nios2: switch to kernel_clone() m68k: switch to kernel_clone() ia64: switch to kernel_clone() h8300: switch to kernel_clone() fork: introduce kernel_clone()
120 lines
3.6 KiB
C
120 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* NOTE: This example is works on x86 and powerpc.
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* Here's a sample kernel module showing the use of kprobes to dump a
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* stack trace and selected registers when kernel_clone() is called.
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*
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* For more information on theory of operation of kprobes, see
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* Documentation/trace/kprobes.rst
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*
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* You will see the trace data in /var/log/messages and on the console
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* whenever kernel_clone() is invoked to create a new process.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/kprobes.h>
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#define MAX_SYMBOL_LEN 64
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static char symbol[MAX_SYMBOL_LEN] = "kernel_clone";
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module_param_string(symbol, symbol, sizeof(symbol), 0644);
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/* For each probe you need to allocate a kprobe structure */
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static struct kprobe kp = {
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.symbol_name = symbol,
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};
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/* kprobe pre_handler: called just before the probed instruction is executed */
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static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
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{
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#ifdef CONFIG_X86
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pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->ip, regs->flags);
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#endif
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#ifdef CONFIG_PPC
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pr_info("<%s> pre_handler: p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
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p->symbol_name, p->addr, regs->nip, regs->msr);
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#endif
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#ifdef CONFIG_MIPS
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pr_info("<%s> pre_handler: p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status);
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#endif
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#ifdef CONFIG_ARM64
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pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx,"
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" pstate = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> pre_handler: p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->psw.addr, regs->flags);
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#endif
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/* A dump_stack() here will give a stack backtrace */
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return 0;
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}
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/* kprobe post_handler: called after the probed instruction is executed */
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static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
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unsigned long flags)
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{
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#ifdef CONFIG_X86
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pr_info("<%s> post_handler: p->addr = 0x%p, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->flags);
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#endif
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#ifdef CONFIG_PPC
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pr_info("<%s> post_handler: p->addr = 0x%p, msr = 0x%lx\n",
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p->symbol_name, p->addr, regs->msr);
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#endif
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#ifdef CONFIG_MIPS
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pr_info("<%s> post_handler: p->addr = 0x%p, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->cp0_status);
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#endif
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#ifdef CONFIG_ARM64
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pr_info("<%s> post_handler: p->addr = 0x%p, pstate = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->pstate);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> pre_handler: p->addr, 0x%p, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->flags);
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#endif
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}
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/*
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* fault_handler: this is called if an exception is generated for any
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* instruction within the pre- or post-handler, or when Kprobes
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* single-steps the probed instruction.
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*/
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static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
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{
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pr_info("fault_handler: p->addr = 0x%p, trap #%dn", p->addr, trapnr);
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/* Return 0 because we don't handle the fault. */
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return 0;
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}
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/* NOKPROBE_SYMBOL() is also available */
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NOKPROBE_SYMBOL(handler_fault);
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static int __init kprobe_init(void)
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{
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int ret;
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kp.pre_handler = handler_pre;
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kp.post_handler = handler_post;
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kp.fault_handler = handler_fault;
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ret = register_kprobe(&kp);
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if (ret < 0) {
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pr_err("register_kprobe failed, returned %d\n", ret);
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return ret;
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}
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pr_info("Planted kprobe at %p\n", kp.addr);
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return 0;
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}
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static void __exit kprobe_exit(void)
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{
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unregister_kprobe(&kp);
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pr_info("kprobe at %p unregistered\n", kp.addr);
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}
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module_init(kprobe_init)
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module_exit(kprobe_exit)
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MODULE_LICENSE("GPL");
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