On Tue 10-04-18 12:40:47, Cyrill Gorcunov wrote: > On Tue, Apr 10, 2018 at 11:09:17AM +0200, Michal Hocko wrote: > > On Tue 10-04-18 05:52:54, Yang Shi wrote: > > [...] > > > So, introduce a new spinlock in mm_struct to protect the concurrent > > > access to arg_start|end, env_start|end and others except start_brk and > > > brk, which are still protected by mmap_sem to avoid concurrent access > > > from do_brk(). > > > > Is there any fundamental problem with brk using the same lock? > > Seems so. Look into mm/mmap.c:brk syscall which reads and writes > brk value under mmap_sem ('cause of do_brk called inside).
Why cannot we simply use the lock when the value is updated? -- Michal Hocko SUSE Labs