| Message ID | 20230311051712.4095040-11-mcgrof@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | module: avoid userspace pressure on unwanted allocations | expand |
diff --git a/kernel/module/main.c b/kernel/module/main.c index e24323e2c499..909454f9616e 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2713,6 +2713,10 @@ static int early_mod_check(struct load_info *info, int flags) if (err) return err; + err = module_patient_check_exists(info->mod->name); + if (err) + return err; + return 0; }
load_module() will allocate a struct module before even checking if the module is already loaded. This can create unecessary memory pressure since we can easily just check if the module is already present early with the copy of the module information from userspace after we've validated it a bit. This can only be an issue if a system is getting hammered with userspace loading modules. Note that there are two ways to load modules, one is auto-loading in-kernel and that pings back to userspace to just call modprobe. Then userspace itself *is* supposed to check if a module is present before loading it. But we're observing situations where tons of the same module are in effect being loaded. In that situation we can end up allocating memory for module requests which after allocating memory will fail to load. To avoid memory pressure for such stupid cases put a stop gap for them. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> --- kernel/module/main.c | 4 ++++ 1 file changed, 4 insertions(+)