MIPS: kprobes: flush_insn_slot should flush only if probe initialised

Author: Marcin Nowakowski <[email protected]> Thu Jun 8 15:20:32 2017 +0200
Comitter: Ralf Baechle <[email protected]> Thu Jun 8 15:36:03 2017 +0200
Commit: 71b45f431ccbe3eb199c1907a99fb640f998f29a
Gitweb: https://git.linux-mips.org/g/ralf/linux/71b45f431ccb
Branch: linux-4.2-stable

When ftrace is used with kprobes, it is possible for a kprobe to contain
an invalid location (ie. only initialised to 0 and not to a specific
location in the code). Trying to perform a cache flush on such location
leads to a crash r4k_flush_icache_range().

Fixes: c1bf207d6ee1 ("MIPS: kprobe: Add support.")
Signed-off-by: Marcin Nowakowski <[email protected]>
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/16296/
Signed-off-by: Ralf Baechle <[email protected]>
(cherry picked from commit a1497c7641ff53ca3632e87030fc905f73f2e7a5)

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 arch/mips/include/asm/kprobes.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)