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e5ae9b5a65
commit8be9fbd534upstream. Setting filters on an ftrace ops results in some memory being allocated for the filter hashes, which must be freed before the ops can be freed. This can be done by removing every individual element of the hash by calling ftrace_set_filter_ip() or ftrace_set_filter_ips() with `remove` set, but this is somewhat error prone as it's easy to forget to remove an element. Make it easier to clean this up by exporting ftrace_free_filter(), which can be used to clean up all of the filter hashes after an ftrace_ops has been unregistered. Using this, fix the ftrace-direct* samples to free hashes prior to being unloaded. All other code either removes individual filters explicitly or is built-in and already calls ftrace_free_filter(). Link: https://lkml.kernel.org/r/20230103124912.2948963-3-mark.rutland@arm.com Cc: stable@vger.kernel.org Cc: Florent Revest <revest@chromium.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes:e1067a07cf("ftrace/samples: Add module to test multi direct modify interface") Fixes:5fae941b9a("ftrace/samples: Add multi direct interface test module") Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
160 lines
4.1 KiB
C
160 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/module.h>
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#include <linux/kthread.h>
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#include <linux/ftrace.h>
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#include <asm/asm-offsets.h>
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extern void my_direct_func1(unsigned long ip);
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extern void my_direct_func2(unsigned long ip);
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void my_direct_func1(unsigned long ip)
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{
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trace_printk("my direct func1 ip %lx\n", ip);
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}
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void my_direct_func2(unsigned long ip)
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{
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trace_printk("my direct func2 ip %lx\n", ip);
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}
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extern void my_tramp1(void *);
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extern void my_tramp2(void *);
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#ifdef CONFIG_X86_64
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#include <asm/ibt.h>
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asm (
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" .pushsection .text, \"ax\", @progbits\n"
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" .type my_tramp1, @function\n"
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" .globl my_tramp1\n"
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" my_tramp1:"
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ASM_ENDBR
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" pushq %rbp\n"
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" movq %rsp, %rbp\n"
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" pushq %rdi\n"
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" movq 8(%rbp), %rdi\n"
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" call my_direct_func1\n"
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" popq %rdi\n"
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" leave\n"
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ASM_RET
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" .size my_tramp1, .-my_tramp1\n"
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" .type my_tramp2, @function\n"
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" .globl my_tramp2\n"
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" my_tramp2:"
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ASM_ENDBR
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" pushq %rbp\n"
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" movq %rsp, %rbp\n"
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" pushq %rdi\n"
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" movq 8(%rbp), %rdi\n"
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" call my_direct_func2\n"
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" popq %rdi\n"
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" leave\n"
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ASM_RET
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" .size my_tramp2, .-my_tramp2\n"
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" .popsection\n"
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);
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#endif /* CONFIG_X86_64 */
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#ifdef CONFIG_S390
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asm (
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" .pushsection .text, \"ax\", @progbits\n"
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" .type my_tramp1, @function\n"
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" .globl my_tramp1\n"
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" my_tramp1:"
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" lgr %r1,%r15\n"
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" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
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" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
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" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
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" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
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" lgr %r2,%r0\n"
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" brasl %r14,my_direct_func1\n"
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" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
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" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
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" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
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" lgr %r1,%r0\n"
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" br %r1\n"
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" .size my_tramp1, .-my_tramp1\n"
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"\n"
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" .type my_tramp2, @function\n"
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" .globl my_tramp2\n"
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" my_tramp2:"
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" lgr %r1,%r15\n"
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" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
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" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
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" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
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" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
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" lgr %r2,%r0\n"
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" brasl %r14,my_direct_func2\n"
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" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
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" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
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" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
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" lgr %r1,%r0\n"
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" br %r1\n"
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" .size my_tramp2, .-my_tramp2\n"
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" .popsection\n"
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);
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#endif /* CONFIG_S390 */
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static unsigned long my_tramp = (unsigned long)my_tramp1;
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static unsigned long tramps[2] = {
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(unsigned long)my_tramp1,
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(unsigned long)my_tramp2,
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};
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static struct ftrace_ops direct;
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static int simple_thread(void *arg)
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{
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static int t;
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int ret = 0;
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while (!kthread_should_stop()) {
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set_current_state(TASK_INTERRUPTIBLE);
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schedule_timeout(2 * HZ);
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if (ret)
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continue;
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t ^= 1;
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ret = modify_ftrace_direct_multi(&direct, tramps[t]);
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if (!ret)
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my_tramp = tramps[t];
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WARN_ON_ONCE(ret);
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}
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return 0;
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}
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static struct task_struct *simple_tsk;
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static int __init ftrace_direct_multi_init(void)
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{
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int ret;
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ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
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ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
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ret = register_ftrace_direct_multi(&direct, my_tramp);
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if (!ret)
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simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
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return ret;
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}
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static void __exit ftrace_direct_multi_exit(void)
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{
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kthread_stop(simple_tsk);
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unregister_ftrace_direct_multi(&direct, my_tramp);
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ftrace_free_filter(&direct);
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}
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module_init(ftrace_direct_multi_init);
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module_exit(ftrace_direct_multi_exit);
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MODULE_AUTHOR("Jiri Olsa");
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MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()");
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MODULE_LICENSE("GPL");
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