• Roland McGrath's avatar
    [PATCH] wait4 PTRACE_ATTACH race fix · 7f2a5255
    Roland McGrath authored
    Back about a year ago when I last fiddled heavily with the do_wait code, I
    was thinking too hard about the wrong thing and I now think I introduced a
    bug whose inverse thought I was fixing.
    Apparently noone was looking too hard over much shoulder, so as to cite my
    bogus reasoning at the time.  In the race condition when PTRACE_ATTACH is
    about to steal a child and then the child hits a tracing event (what
    my_ptrace_child checks for), the real parent does need to set its flag
    noting it has some eligible live children.  Otherwise a spurious ECHILD
    error is possible, since the child in question is not yet on the
    ptrace_children list.
    Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
exit.c 39.6 KB