On Mon 2023-05-29 16:50:45, Miguel Ojeda wrote: > On Mon, May 29, 2023 at 1:08 PM Maninder Singh <maninder...@samsung.com> > wrote: > > > > I Will add co-developed-by` tag. > > because this change was identified while we were working on kallsyms some > > time back. > > https://lore.kernel.org/lkml/yontol4zc4cyt...@infradead.org/t/ > > > > this patch set is pending and we will start working on that again, so i > > thought better > > to send bugfix first. > > Sounds good to me! > > (Fixed Wedson's email address) > > > Yes, I think second buffer was not related to kallsyms, so I have not > > touched that. > > Kees: what is the current stance on `[static N]` parameters? Something like: > > const char *kallsyms_lookup(unsigned long addr, > unsigned long *symbolsize, > unsigned long *offset, > - char **modname, char *namebuf); > + char **modname, char namebuf[static > KSYM_NAME_LEN]); > > makes the compiler complain about cases like these (even if trivial): > > arch/powerpc/xmon/xmon.c:1711:10: error: array argument is too small; > contains 128 elements, callee requires at least 512 > [-Werror,-Warray-bounds] > name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr); > ^ ~~~~~~ > ./include/linux/kallsyms.h:86:29: note: callee declares array > parameter as static here > char **modname, char namebuf[static KSYM_NAME_LEN]); > ^ ~~~~~~~~~~~~~~~~~~~~~~ > > But I only see 2 files in the kernel using `[static N]` (from 2020 and > 2021). Should something else be used instead (e.g. `__counted_by`), > even if constexpr-sized?. > > Also, I went through the other callers to `kallsyms_lookup` to see > other issues -- one I am not sure about is `fetch_store_symstring` in > `kernel/trace/trace_probe_tmpl.h`. Steven/Masami: is that "with max > length" in the function docs enough? Is it 0xffff?
The best solution would be to pass the buffer size as an extra parameter. Especially when some code passes buffers that are allocated/reserved dynamically. Sigh, I am not sure how many changes it would require in kallsyms API and all the callers. But it would be really appreciated, IMHO. Best Regards, Petr
