On 07/14, David Ahern wrote: > > On 7/14/15 1:47 PM, Oleg Nesterov wrote: >>> >>> if (show_flags & TASK_DIAG_SHOW_VMA) { >>> + /* if the request is to dump all threads of all processes >>> + * only show VMAs for group leader. >>> + */ >>> + if (req->dump_strategy == TASK_DIAG_DUMP_ALL_THREAD && >>> + !thread_group_leader(tsk)) >>> + goto done; >>> + >> >> This doesn't look right, group leader can be a zombie with ->mm == NULL, > > Seriously? Yes, the main thread can do sys_exit() / pthread_exit(), although this is not that common. > I'll find some way to track whether VMAs have been dumped for > a pid. In case I confused you, the thread_group_leader() check and "goto done" above are fine, just you can't trust tsk->mm, so >>> if (i >= n) >>> err = fill_vma(tsk, skb, cb, &progress, show_flags); >> >> so this probably needs something like find_lock_task_mm(). > > ok. Yes, you just need to (try) find a subthread with ->mm != NULL if !tsk->mm, find_lock_task_mm() can help. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html