Re: [PATCH] mm/ksm: fix ksm_exit() deadlock on exec error path

["David Hildenbrand (Arm)" <david@kernel.org>]

On 11/6/26 02:39, Jinjiang Tu wrote:
> create_init_stack_vma() registers the new mm with ksmd via ksm_execve()
> while holding mmap_write_lock(), and calls ksm_exit() before dropping the
> lock. When insert_vm_struct() fails, __ksm_exit() takes mmap_write_lock()
> again when the mm is ksmd's current scan cursor, leading to deadlock.
> 
> The early registration is no longer needed after commit 590c03ca6a3f
> ("mm/ksm: fix exec/fork inheritance support for prctl"). ksm_vma_flags()
> calls __ksm_enter() when the first mergeable VMA is created. Remove
> ksm_execve() and its stubs.

I assume you mean the

} else if (mm_slot) {
	mmap_write_lock(mm);
	mmap_write_unlock(mm);
}

Can that actually trigger?

IOW, can we have an slot, and the slot can already have a mm_slot->rmap_list?

-- 
Cheers,

David