diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2009-04-02 16:58:14 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-06-15 09:40:20 -0700 |
| commit | 8842593368490116911712ea5aaf6ea9dd2db7bb (patch) | |
| tree | 2487291ebcdd5b3c98a0d37522440e3268c5718b /kernel | |
| parent | 64cd4669da13c829635f0b668a6bd546ee472e01 (diff) | |
ptrace: fix possible zombie leak on PTRACE_DETACH
commit 4576145c1ecdaaea9ef8976a48335206aa1ebf91 upstream.
When ptrace_detach() takes tasklist, the tracee can be SIGKILL'ed. If it
has already passed exit_notify() we can leak a zombie, because a) ptracing
disables the auto-reaping logic, and b) ->real_parent was not notified
about the child's death.
ptrace_detach() should follow the ptrace_exit's logic, change the code
accordingly.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Tested-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/ptrace.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 2f5ec7a571a..893c2c7615d 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -237,6 +237,8 @@ out: int ptrace_detach(struct task_struct *child, unsigned int data) { + int dead = 0; + if (!valid_signal(data)) return -EIO; @@ -244,18 +246,21 @@ int ptrace_detach(struct task_struct *child, unsigned int data) ptrace_disable(child); clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); - /* protect against de_thread()->release_task() */ write_lock_irq(&tasklist_lock); + /* protect against de_thread()->release_task() */ if (child->ptrace) { child->exit_code = data; - __ptrace_unlink(child); + dead = __ptrace_detach(current, child); if (!child->exit_state) wake_up_process(child); } write_unlock_irq(&tasklist_lock); + if (unlikely(dead)) + release_task(child); + return 0; } |