| Summary: | procfs probes should not put strings on kernel stack | ||
|---|---|---|---|
| Product: | systemtap | Reporter: | Frank Ch. Eigler <fche> |
| Component: | translator | Assignee: | David Smith <dsmith> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | ||
| Priority: | P2 | ||
| Version: | unspecified | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
Fixed in commit 8e0049e. Now procfs probes (read or write) do not put strings on the kernel stack. Resolved. |
The implementation of _st_procfs_{read,write} use a string_t temporary on the ordinary stack (strdata). It must not do that, since MAXSTRINGLEN could be large enough to overflow the kernel stack, which may or may not be suspected/detected at compile time. Rather, such stuff needs to go into the context directly. stap -DMAXSTRINGLEN=16384 -e ' { probe procfs("foo").write { log($value) }'