On Tue 17-10-17 20:26:14, Baoquan He wrote: > Hi Michal, > > Earlier I posted a patchset to clean up these in a different way, but > patches sent to your below mail address are all rejected. > > <[email protected]>: host mail.kerne.org[104.131.33.237] said: 454 4.1.1 > <[email protected]>: Recipient address rejected: User unknown in virtual > mailbox table (in reply to RCPT TO command)
yes, there was a typo in the email address which I've fixed up in the reply... Your cleanup was mostly about replacing vm_mmap by get_unmaped_area which is an independent issue to what I am trying to achieve here. > On 10/16/17 at 03:44pm, Michal Hocko wrote: > > From: Michal Hocko <[email protected]> > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > > index 6466153f2bf0..09456e2add18 100644 > > --- a/fs/binfmt_elf.c > > +++ b/fs/binfmt_elf.c > > @@ -341,6 +341,29 @@ create_elf_tables(struct linux_binprm *bprm, struct > > elfhdr *exec, > > > > #ifndef elf_map > > > > +static unsigned long elf_vm_mmap(struct file *filep, unsigned long addr, > > + unsigned long size, int prot, int type, unsigned long off) > > +{ > > + unsigned long map_addr; > > + > > + /* > > + * If caller requests the mapping at a specific place, make sure we fail > > + * rather than potentially clobber an existing mapping which can have > > + * security consequences (e.g. smash over the stack area). > > + */ > > + map_addr = vm_mmap(filep, addr, size, prot, type & ~MAP_FIXED, off); > > + if (BAD_ADDR(map_addr)) > > + return map_addr; > > + > > + if ((type & MAP_FIXED) && map_addr != addr) { > > + pr_info("Uhuuh, elf segement at %p requested but the memory is > > mapped already\n", > > + (void*)addr); > > + return -EAGAIN; > > + } > > + > > + return map_addr; > > +} > > + > > static unsigned long elf_map(struct file *filep, unsigned long addr, > > struct elf_phdr *eppnt, int prot, int type, > > unsigned long total_size) > > @@ -366,11 +389,11 @@ static unsigned long elf_map(struct file *filep, > > unsigned long addr, > > */ > > if (total_size) { > > total_size = ELF_PAGEALIGN(total_size); > > - map_addr = vm_mmap(filep, addr, total_size, prot, type, off); > > + map_addr = elf_vm_mmap(filep, addr, total_size, prot, type, > > off); > > if (!BAD_ADDR(map_addr)) > > vm_munmap(map_addr+size, total_size-size); > > Here we will still take the map total, then unmap the rest way. > > I am wondering why we don't fix those issues we figured out, but add > another level of wrapper elf_vm_mmap() to hack it. Could you be more specific please? > So we will have > elf_map() -> elf_vm_mmap() -> vm_mmap(), not even counting > vm_mmap_pgoff(), then finally enter into do_mmap_pgoff(), to do the > maping for elf program. I've added another level of helper to keep the code in elf_map saner. It is quite complex already. -- Michal Hocko SUSE Labs
