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author | 2018-11-20 12:40:25 -0500 | |
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committer | 2018-11-27 20:31:54 -0500 | |
commit | 7c6ea35ef50810aa12ab26f21cb858d980881576 (patch) | |
tree | 9fc799fd26232ec5a9018d33d965bb048947aab8 /kernel | |
parent | function_graph: Move return callback before update of curr_ret_stack (diff) | |
download | linux-7c6ea35ef50810aa12ab26f21cb858d980881576.tar.gz linux-7c6ea35ef50810aa12ab26f21cb858d980881576.tar.bz2 linux-7c6ea35ef50810aa12ab26f21cb858d980881576.zip |
function_graph: Reverse the order of pushing the ret_stack and the callback
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: 03274a3ffb449 ("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>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/trace_functions_graph.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 4f0d72ae6362..2561460d7baf 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -188,15 +188,17 @@ int function_graph_enter(unsigned long ret, unsigned long func, trace.func = func; trace.depth = ++current->curr_ret_depth; - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - goto out; - if (ftrace_push_return_trace(ret, func, frame_pointer, retp)) goto out; + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) + goto out_ret; + return 0; + out_ret: + current->curr_ret_stack--; out: current->curr_ret_depth--; return -EBUSY; |