x86/insn-eval: Handle return values from the decoder

stable inclusion
from stable-v5.10.133
commit e6f8dc86a1c15b862486a61abcb54b88e8c177e3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YVKO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e6f8dc86a1c15b862486a61abcb54b88e8c177e3



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commit 6e8c83d2 upstream.

Now that the different instruction-inspecting functions return a value,
test that and return early from callers if error has been encountered.

While at it, do not call insn_get_modrm() when calling
insn_get_displacement() because latter will make sure to call
insn_get_modrm() if ModRM hasn't been parsed yet.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210304174237.31945-6-bp@alien8.de


Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>