On Mon, Jan 24, 2011 at 17:24, Stefano Bonifazi wrote: >> how can the ldso possibly prevent clashes ? it has no idea what >> addresses an app will ask for at runtime. >> >> plus, if the kernel is employing ASLR (which isnt uncommon nowadays), >> the load addresses could be anywhere. > > Well not alone, in my mind ld.so asks the memory manager through calling > mmap where it can map the shared modules inside the process address space.. > the memory manager should know what addresses are free and which are taken > .. then when the process code requires dynamic memory allocation, it does it > again through the memory manager (i.e. malloc) avoiding of allocating memory > where shared modules have been loaded into.. > Again with ASLR I think the mmu should be aware of all used memory slots, > avoiding conflicts..
i'm not saying conflicts arent noticed. i'm saying that there is no way for the surrounding system (ldso/linux mm/...) to know ahead of time what the app is going to request with MAP_FIXED and thus prevent possible future conflicts. -mike
