function_graph: Reverse the order of pushing the ret_stack and the callback
commit 7c6ea35ef50810aa12ab26f21cb858d980881576 upstream.
The function graph profiler uses the ret_stack to store the "subtime" and
reuse it by nested functions and also on the return. But the current logic
has the profiler callback called before the ret_stack is updated, and it is
just modifying the ret_stack that will later be allocated (it's just lucky
that the "subtime" is not touched when it is allocated).
This could also cause a crash if we are at the end of the ret_stack when
this happens.
By reversing the order of the allocating the ret_stack and then calling the
callbacks attached to a function being traced, the ret_stack entry is no
longer used before it is allocated.
Cc: stable@kernel.org
Fixes: 03274a3ffb
("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
d2bcf809e8
commit
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@ -188,15 +188,17 @@ int function_graph_enter(unsigned long ret, unsigned long func,
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trace.func = func;
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trace.func = func;
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trace.depth = ++current->curr_ret_depth;
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trace.depth = ++current->curr_ret_depth;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace))
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goto out;
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if (ftrace_push_return_trace(ret, func,
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if (ftrace_push_return_trace(ret, func,
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frame_pointer, retp))
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frame_pointer, retp))
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goto out;
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goto out;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace))
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goto out_ret;
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return 0;
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return 0;
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out_ret:
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current->curr_ret_stack--;
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out:
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out:
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current->curr_ret_depth--;
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current->curr_ret_depth--;
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return -EBUSY;
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return -EBUSY;
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