Re: kernel BUG at mm/gup.c:LINE!

[Oscar Salvador <osalvador@techadventures.net>]

> A strange thing is that __mm_populate() is only called by do_mlock() from mm/mlock.c,
> which makes len PAGE_ALIGN already. That VM_BUG_ON should not be triggered.

Unless I overlooked something, __mm_populate() gets called from:

load_elf_library() -> vm_brk() -> vm_brk_flags():

vm_brk_flags() {
	...
	populate = ((mm->def_flags & VM_LOCKED) != 0);
	...
	if (populate && !ret)
		mm_populate(addr, len);
}

mm_populate() -> __mm_populate():

__mm_populate() {
	...
	VM_BUG_ON(len != PAGE_ALIGN(len));
	...
}


In load_elf_library(), we have:

len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
			    ELF_MIN_ALIGN - 1);
bss = eppnt->p_memsz + eppnt->p_vaddr;
if (bss > len) {
	error = vm_brk(len, bss - len);
	if (error)
		goto out_free_ph;
}

So len gets page aligned, but not bss (eppnt->p_memsz + eppnt->p_vaddr), maybe that's the problem?


-- 
Oscar Salvador
SUSE L3