On Sat, Apr 12, 2025 at 10:32 PM Menglong Dong <[email protected]> wrote: > > On Sat, Apr 12, 2025 at 10:09 PM Steven Rostedt <[email protected]> wrote: > > > > On Sat, 12 Apr 2025 21:33:48 +0800 > > Menglong Dong <[email protected]> wrote: > > > > > The max ftrace hash bits is made fls(32) in register_ftrace_direct(), > > > which seems illogical, and it seems to be a spelling mistake. > > > > > > Just fix it. > > > > > > (Do I misunderstand something?) > > > > I think the logic is incorrect and this patch doesn't fix it. > > > > > > > > Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash > > > while in use") > > > Signed-off-by: Menglong Dong <[email protected]> > > > --- > > > kernel/trace/ftrace.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > > index 1a48aedb5255..7697605a41e6 100644 > > > --- a/kernel/trace/ftrace.c > > > +++ b/kernel/trace/ftrace.c > > > @@ -5914,7 +5914,7 @@ int register_ftrace_direct(struct ftrace_ops *ops, > > > unsigned long addr) > > > > > > /* Make a copy hash to place the new and the old entries in */ > > > size = hash->count + direct_functions->count; > > > - if (size > 32) > > > + if (size < 32) > > > size = 32; > > > new_hash = alloc_ftrace_hash(fls(size)); > > > if (!new_hash) > > > > The above probably should be: > > > > size = hash->count + direct_functions->count > > size = fls(size); > > if (size > FTRACE_HASH_MAX_BITS) > > size = FTRACE_HASH_MAX_BITS; > > new_hash = alloc_ftrace_hash(size); > > Yeah, this seems to make more sense. And I'll send a V2 > later. > > BTW, Should we still keep the "size = min(size, 32)" logic
Oops, I mean "size = max(size, 32); size = fls(size);" here :/ > to avoid the hash bits being too small, just like the origin > logic in "dup_hash"? > > Thanks! > Menglong Dong > > > > > -- Steve > > > >
