1. 18 Apr, 2008 2 commits
    • Roland McGrath's avatar
      ptrace_signal subroutine · 18c98b65
      Roland McGrath authored
      This breaks out the ptrace handling from get_signal_to_deliver into a
      new subroutine.  The actual code there doesn't change, and it gets
      inlined into nearly identical compiled code.  This makes the function
      substantially shorter and thus easier to read, and it nicely isolates
      the ptrace magic.
      Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
      Acked-by: default avatarKyle McMartin <kyle@mcmartin.ca>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      18c98b65
    • Li Zefan's avatar
      cgroup: fix a race condition in manipulating tsk->cg_list · 0e04388f
      Li Zefan authored
      When I ran a test program to fork mass processes and at the same time
      'cat /cgroup/tasks', I got the following oops:
      
        ------------[ cut here ]------------
        kernel BUG at lib/list_debug.c:72!
        invalid opcode: 0000 [#1] SMP
        Pid: 4178, comm: a.out Not tainted (2.6.25-rc9 #72)
        ...
        Call Trace:
         [<c044a5f9>] ? cgroup_exit+0x55/0x94
         [<c0427acf>] ? do_exit+0x217/0x5ba
         [<c0427ed7>] ? do_group_exit+0.65/0x7c
         [<c0427efd>] ? sys_exit_group+0xf/0x11
         [<c0404842>] ? syscall_call+0x7/0xb
         [<c05e0000>] ? init_cyrix+0x2fa/0x479
        ...
        EIP: [<c04df671>] list_del+0x35/0x53 SS:ESP 0068:ebc7df4
        ---[ end trace caffb7332252612b ]---
        Fixing recursive fault but reboot is needed!
      
      After digging into the code and debugging, I finlly found out a race
      situation:
      
      				do_exit()
      				  ->cgroup_exit()
      				    ->if (!list_empty(&tsk->cg_list))
      				        list_del(&tsk->cg_list);
      
        cgroup_iter_start()
          ->cgroup_enable_task_cg_list()
            ->list_add(&tsk->cg_list, ..);
      
      In this case the list won't be deleted though the process has exited.
      
      We got two bug reports in the past, which seem to be the same bug as
      this one:
      	http://lkml.org/lkml/2008/3/5/332
      	http://lkml.org/lkml/2007/10/17/224
      
      Actually sometimes I got oops on list_del, sometimes oops on list_add.
      And I can change my test program a bit to trigger other oops.
      
      The patch has been tested both on x86_32 and x86_64.
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Acked-by: default avatarPaul Menage <menage@google.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: stable@kernel.org
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0e04388f
  2. 17 Apr, 2008 2 commits
  3. 16 Apr, 2008 36 commits