233a806b00
- Some kernel-doc cleanups. That script is still regex onslaught from
hell, but it has gotten a little better.
- Improvements to the checkpatch docs, which are also used by the tool
itself.
- A major update to the pathname lookup documentation.
- Elimination of :doc: markup, since our automarkup magic can create
references from filenames without all the extra noise.
- The flurry of Chinese translation activity continues.
Plus, of course, the usual collection of updates, typo fixes, and warning
fixes.
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Merge tag 'docs-5.14' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"This was a reasonably active cycle for documentation; this includes:
- Some kernel-doc cleanups. That script is still regex onslaught from
hell, but it has gotten a little better.
- Improvements to the checkpatch docs, which are also used by the
tool itself.
- A major update to the pathname lookup documentation.
- Elimination of :doc: markup, since our automarkup magic can create
references from filenames without all the extra noise.
- The flurry of Chinese translation activity continues.
Plus, of course, the usual collection of updates, typo fixes, and
warning fixes"
* tag 'docs-5.14' of git://git.lwn.net/linux: (115 commits)
docs: path-lookup: use bare function() rather than literals
docs: path-lookup: update symlink description
docs: path-lookup: update get_link() ->follow_link description
docs: path-lookup: update WALK_GET, WALK_PUT desc
docs: path-lookup: no get_link()
docs: path-lookup: update i_op->put_link and cookie description
docs: path-lookup: i_op->follow_link replaced with i_op->get_link
docs: path-lookup: Add macro name to symlink limit description
docs: path-lookup: remove filename_mountpoint
docs: path-lookup: update do_last() part
docs: path-lookup: update path_mountpoint() part
docs: path-lookup: update path_to_nameidata() part
docs: path-lookup: update follow_managed() part
docs: Makefile: Use CONFIG_SHELL not SHELL
docs: Take a little noise out of the build process
docs: x86: avoid using ReST :doc:`foo` markup
docs: virt: kvm: s390-pv-boot.rst: avoid using ReST :doc:`foo` markup
docs: userspace-api: landlock.rst: avoid using ReST :doc:`foo` markup
docs: trace: ftrace.rst: avoid using ReST :doc:`foo` markup
docs: trace: coresight: coresight.rst: avoid using ReST :doc:`foo` markup
...
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#define pr_fmt(fmt) "%s: " fmt, __func__
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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> 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> 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> 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> p->addr = 0x%p, pc = 0x%lx, 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_ARM
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pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->ARM_pc, (long)regs->ARM_cpsr);
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#endif
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#ifdef CONFIG_RISCV
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pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->epc, regs->status);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> 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> 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> 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> 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> 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_ARM
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pr_info("<%s> p->addr = 0x%p, cpsr = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->ARM_cpsr);
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#endif
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#ifdef CONFIG_RISCV
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pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->status);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> 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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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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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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