tracing: Bound histogram expression strings with seq_buf

expr_str() allocates a fixed MAX_FILTER_STR_VAL buffer and then builds
expression names with a series of raw strcat() appends. Nested operands,
constants, field flags, and generated field names can push the rendered
string past that fixed limit before the name is attached to the hist
field.

Build expression strings with seq_buf and return -E2BIG when the
rendered name would exceed MAX_FILTER_STR_VAL. This keeps the existing
tracing-side limit while replacing the raw append logic with bounded
construction.

Link: https://patch.msgid.link/20260611055945.22348-4-pengpeng@iscas.ac.cn
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

0 files changed, 0 insertions, 0 deletions