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authorDmitry Torokhov <[email protected]>2020-01-10 14:56:04 -0800
committerDmitry Torokhov <[email protected]>2020-01-10 14:56:04 -0800
commit1bdd3e05a0a3b4a97ea88bc46fef8fb265c8b94c (patch)
tree2244894a9ea0c941a8f32e5f3d196b4ea0eae24b /kernel/trace/fgraph.c
parent643dd7416649bea2e8c61d8fdeeefb409a0ca5eb (diff)
parentc79f46a282390e0f5b306007bf7b11a46d529538 (diff)
Merge tag 'v5.5-rc5' into next
Sync up with mainline to get SPI "delay" API changes.
Diffstat (limited to 'kernel/trace/fgraph.c')
-rw-r--r--kernel/trace/fgraph.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 7950a0356042..a2659735db73 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -101,6 +101,15 @@ int function_graph_enter(unsigned long ret, unsigned long func,
{
struct ftrace_graph_ent trace;
+ /*
+ * Skip graph tracing if the return location is served by direct trampoline,
+ * since call sequence and return addresses is unpredicatable anymore.
+ * Ex: BPF trampoline may call original function and may skip frame
+ * depending on type of BPF programs attached.
+ */
+ if (ftrace_direct_func_count &&
+ ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
+ return -EBUSY;
trace.func = func;
trace.depth = ++current->curr_ret_depth;
@@ -332,9 +341,14 @@ int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
return 0;
}
+/*
+ * Simply points to ftrace_stub, but with the proper protocol.
+ * Defined by the linker script in linux/vmlinux.lds.h
+ */
+extern void ftrace_stub_graph(struct ftrace_graph_ret *);
+
/* The callbacks that hook a function */
-trace_func_graph_ret_t ftrace_graph_return =
- (trace_func_graph_ret_t)ftrace_stub;
+trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph;
trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
@@ -614,7 +628,7 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
goto out;
ftrace_graph_active--;
- ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
+ ftrace_graph_return = ftrace_stub_graph;
ftrace_graph_entry = ftrace_graph_entry_stub;
__ftrace_graph_entry = ftrace_graph_entry_stub;
ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);