mirror of https://gitee.com/openkylin/linux.git
powerpc/kprobes: Pause function_graph tracing during jprobes handling
This fixes a crash when function_graph and jprobes are used together. This is essentially commit237d28db03
("ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing"), but for powerpc. Jprobes breaks function_graph tracing since the jprobe hook needs to use jprobe_return(), which never returns back to the hook, but instead to the original jprobe'd function. The solution is to momentarily pause function_graph tracing before invoking the jprobe hook and re-enable it when returning back to the original jprobe'd function. Fixes:6794c78243
("powerpc64: port of the function graph tracer") Cc: stable@vger.kernel.org # v2.6.30+ Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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@ -617,6 +617,15 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
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regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
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#endif
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/*
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* jprobes use jprobe_return() which skips the normal return
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* path of the function, and this messes up the accounting of the
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* function graph tracer.
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*
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* Pause function graph tracing while performing the jprobe function.
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*/
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pause_graph_tracing();
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return 1;
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}
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NOKPROBE_SYMBOL(setjmp_pre_handler);
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@ -642,6 +651,8 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
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* saved regs...
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*/
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memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
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/* It's OK to start function graph tracing again */
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unpause_graph_tracing();
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preempt_enable_no_resched();
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return 1;
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}
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