On Tue, Jun 11, 2019 at 06:09:24AM +0900, Masahiro Yamada wrote: > This function never attempts to allocate memory, so returning -ENOMEM > looks weird to me. The reason of the failure is there is no more space > in the given kobj_uevent_env structure. > > Let's change the error code to -ENOSPC. > > This patch is safe since this function had never failed in reality. > > The callers of this function put a fixed number of small strings into > the buffer. > > The buffer is defined to be large enough: > > #define UEVENT_NUM_ENVP 32 /* number of env pointers */ > #define UEVENT_BUFFER_SIZE 2048 /* buffer for the variables > */ > > As you see WARN() in the error paths, any failure of this function is > a software bug. > > If such a case had ever happened before, you would have already seen > a noisy back-trace, then you would have increased UEVENT_NUM_ENVP or > UEVENT_BUFFER_SIZE. > > Nobody has ever increased UEVENT_NUM_ENVP or UEVENT_BUFFER_SIZE since > their addition, that is, this structure is always large enough.
That implies that we should just drop the WARN() entirely. Especially given that syzbot runs panic-on-warn, right? How about doing both things at the same time? thanks, greg k-h
