Re: [RFC] : Is /proc/kcore still usefull and/or maintained ?

Eric Dumazet
2007-03-21T23:54:09Z

I stand corrected : This is a new bug

The /proc/kcore problem appears with linux-2.6.21-rc4-mm1

fd = open("/proc/kcore", 0);
llseek(fd, ...) returns an -EINVAL error

Quick code inspection (before going to sleep...) shows that

proc_reg_llseek() (file fs/proc/inode.c)

is doing something like :

rv = -EINVAL;
llseek = pde->proc_fops->llseek;
spin_unlock(&pde->pde_unload_lock);
if (llseek)
rv = llseek(file, offset, whence);

As kcore dont have a .llseek handler, proc_reg_llseek() returns -EINVAL;

Previous kernel was probably calling a default llseek() handler.

if (!llseek)
llseek = default_llseek;

Hum ???