On Thu, Sep 14, 2023 at 10:02:03AM -0700, Andrew Morton wrote: > On Thu, 14 Sep 2023 12:30:20 -0400 Ben Wolsieffer <ben.wolsieffer@xxxxxxxxxxx> wrote: > > > The no-MMU implementation of /proc/<pid>/map doesn't normally release > > the mmap read lock, because it uses !IS_ERR_OR_NULL(_vml) to determine > > whether to release the lock. Since _vml is NULL when the end of the > > mappings is reached, the lock is not released. > > > > Thanks. Is this bug demonstrable from userspace? If so, how? Yes, run "cat /proc/1/maps" twice. You should observe that the second run hangs.
