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| author | Eric W. Biederman <ebiederm@xmission.com> | 2006-03-28 16:10:58 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-28 18:36:40 -0800 |
| commit | fef23e7fbb11a0a78cd61935f7056bc2b237995a (patch) | |
| tree | a6ff460b3a5d11d01c0532de561eb81183e056c2 | |
| parent | ca9ba4471c1203bb6e759b76e83167fec54fe590 (diff) | |
| download | linux-fef23e7fbb11a0a78cd61935f7056bc2b237995a.tar.gz linux-fef23e7fbb11a0a78cd61935f7056bc2b237995a.tar.bz2 linux-fef23e7fbb11a0a78cd61935f7056bc2b237995a.zip | |
[PATCH] exec: allow init to exec from any thread.
After looking at the problem of init calling exec some more I figured out
an easy way to make the code work.
The actual symptom without out this patch is that all threads will die
except pid == 1, and the thread calling exec. The thread calling exec will
wait forever for pid == 1 to die.
Since pid == 1 does not install a handler for SIGKILL it will never die.
This modifies the tests for init from current->pid == 1 to the equivalent
current == child_reaper. And then it causes exec in the ugly case to
modify child_reaper.
The only weird symptom is that you wind up with an init process that
doesn't have the oldest start time on the box.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/exec.c | 13 | ||||
| -rw-r--r-- | kernel/exit.c | 2 | ||||
| -rw-r--r-- | kernel/signal.c | 2 |
3 files changed, 14 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c index c7397c46ad6d..d0ecea0781f7 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -660,12 +660,23 @@ static int de_thread(struct task_struct *tsk) struct dentry *proc_dentry1, *proc_dentry2; unsigned long ptrace; + leader = current->group_leader; + /* + * If our leader is the child_reaper become + * the child_reaper and resend SIGKILL signal. + */ + if (unlikely(leader == child_reaper)) { + write_lock(&tasklist_lock); + child_reaper = current; + zap_other_threads(current); + write_unlock(&tasklist_lock); + } + /* * Wait for the thread group leader to be a zombie. * It should already be zombie at this point, most * of the time. */ - leader = current->group_leader; while (leader->exit_state != EXIT_ZOMBIE) yield(); diff --git a/kernel/exit.c b/kernel/exit.c index a8c7efc7a681..223a8802b665 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -807,7 +807,7 @@ fastcall NORET_TYPE void do_exit(long code) panic("Aiee, killing interrupt handler!"); if (unlikely(!tsk->pid)) panic("Attempted to kill the idle task!"); - if (unlikely(tsk->pid == 1)) + if (unlikely(tsk == child_reaper)) panic("Attempted to kill init!"); if (unlikely(current->ptrace & PT_TRACE_EXIT)) { diff --git a/kernel/signal.c b/kernel/signal.c index 75f7341b0c39..dc8f91bf9f89 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1990,7 +1990,7 @@ relock: continue; /* Init gets no signals it doesn't want. */ - if (current->pid == 1) + if (current == child_reaper) continue; if (sig_kernel_stop(signr)) { |