Messages in this thread Patch in this message | | | Subject | [PATCH] exec: Allow init to exec from any thread. | From | (Eric W. Biederman) | Date | Sun, 29 Jan 2006 14:40:19 -0700 |
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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>
---
fs/exec.c | 13 ++++++++++++- kernel/exit.c | 2 +- kernel/signal.c | 2 +- 3 files changed, 14 insertions(+), 3 deletions(-)
96629b6a7cc1bdb3afdd1b5190e08e3df62bfa6a diff --git a/fs/exec.c b/fs/exec.c index 62eca47..348e6ac 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -660,12 +660,23 @@ static int de_thread(struct task_struct 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 93cee36..4059b2a 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -802,7 +802,7 @@ fastcall NORET_TYPE void do_exit(long co 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 (tsk->io_context) exit_io_context(); diff --git a/kernel/signal.c b/kernel/signal.c index 20a67ae..6faf362 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2019,7 +2019,7 @@ relock: continue; /* Init gets no signals it doesn't want. */ - if (current->pid == 1) + if (current == child_reaper) continue; if (sig_kernel_stop(signr)) { -- 1.1.5.g3480 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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