tracing: Reject string operand in the histogram expression

stable inclusion
from stable-5.10.58
commit b2aca8daa50eb48592683e66e204d53b55fe596e
bugzilla: 176984 https://gitee.com/openeuler/kernel/issues/I4E2P4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b2aca8daa50eb48592683e66e204d53b55fe596e

--------------------------------

commit a9d10ca4 upstream.

Since the string type can not be the target of the addition / subtraction
operation, it must be rejected. Without this fix, the string type silently
converted to digits.

Link: https://lkml.kernel.org/r/162742654278.290973.1523000673366456634.stgit@devnote2



Cc: stable@vger.kernel.org
Fixes: 100719dc ("tracing: Add simple expression support to hist triggers")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>