[PATCH 3.10 070/139] kernel/extable.c: mark core_kernel_text notrace

From: Willy Tarreau
Date: Wed Nov 01 2017 - 17:45:02 EST


From: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>

commit c0d80ddab89916273cb97114889d3f337bc370ae upstream.

core_kernel_text is used by MIPS in its function graph trace processing,
so having this method traced leads to an infinite set of recursive calls
such as:

Call Trace:
ftrace_return_to_handler+0x50/0x128
core_kernel_text+0x10/0x1b8
prepare_ftrace_return+0x6c/0x114
ftrace_graph_caller+0x20/0x44
return_to_handler+0x10/0x30
return_to_handler+0x0/0x30
return_to_handler+0x0/0x30
ftrace_ops_no_ops+0x114/0x1bc
core_kernel_text+0x10/0x1b8
core_kernel_text+0x10/0x1b8
core_kernel_text+0x10/0x1b8
ftrace_ops_no_ops+0x114/0x1bc
core_kernel_text+0x10/0x1b8
prepare_ftrace_return+0x6c/0x114
ftrace_graph_caller+0x20/0x44
(...)

Mark the function notrace to avoid it being traced.

Link: http://lkml.kernel.org/r/1498028607-6765-1-git-send-email-marcin.nowakowski@xxxxxxxxxx
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Meyer <thomas@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
kernel/extable.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/extable.c b/kernel/extable.c
index 67460b9..5ec4b6f 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -66,7 +66,7 @@ static inline int init_kernel_text(unsigned long addr)
return 0;
}

-int core_kernel_text(unsigned long addr)
+int notrace core_kernel_text(unsigned long addr)
{
if (addr >= (unsigned long)_stext &&
addr <= (unsigned long)_etext)
--
2.8.0.rc2.1.gbe9624a