The patch titled ptrace: wait_task_zombie: do not account traced sub-threads has been added to the -mm tree. Its filename is ptrace-wait_task_zombie-do-not-account-traced-sub-threads.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: ptrace: wait_task_zombie: do not account traced sub-threads From: Oleg Nesterov <oleg@xxxxxxxxxx> The bug is ancient, the fix doesn't depend on other changes in -mm. If we trace the sub-thread of our natural child and this sub-thread exits, we update parent->signal->cxxx fields. But we should not do this until the whole thread-group exits, otherwise we account this thread (and all other live threads) twice. Add the task_detached() check. No need to check thread_group_empty(), wait_consider_task()->delay_group_leader() already did this. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> Cc: Vitaly Mayatskikh <vmayatsk@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN kernel/exit.c~ptrace-wait_task_zombie-do-not-account-traced-sub-threads kernel/exit.c --- a/kernel/exit.c~ptrace-wait_task_zombie-do-not-account-traced-sub-threads +++ a/kernel/exit.c @@ -1194,7 +1194,7 @@ static int wait_task_zombie(struct task_ traced = ptrace_reparented(p); - if (likely(!traced)) { + if (likely(!traced) && likely(!task_detached(p))) { struct signal_struct *psig; struct signal_struct *sig; struct task_cputime cputime; _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch rework-fix-is_single_threaded.patch getrusage-fill-ru_maxrss-value.patch allow_signal-kill-the-bogus-mm-check-add-a-note-about-clone_sighand.patch ptrace-remove-pt_dtrace-from-arch-h8300.patch ptrace-remove-pt_dtrace-from-avr32-mn10300-parisc-s390-sh-xtensa.patch ptrace-remove-pt_dtrace-from-m68k-m68knommu.patch ptrace-remove-pt_dtrace-from-arch-m32r.patch ptrace-mm_need_new_owner-use-real_parent-to-search-in-the-siblings.patch ptrace-tracehook_unsafe_exec-remove-the-stale-comment.patch ptrace-tracehook_unsafe_exec-remove-the-stale-comment-fix.patch ptrace-do-not-use-task-ptrace-directly-in-core-kernel.patch ptrace-ptrace_attach-check-pf_kthread-exit_state-instead-of-mm.patch ptrace-cleanup-check-set-of-pt_ptraced-during-attach.patch ptrace-do-not-use-task_lock-for-attach.patch ptrace_get_task_struct-s-tasklist-rcu-make-it-static.patch ptrace-wait_task_zombie-s-parent-real_parent.patch ptrace-do_notify_parent_cldstop-fix-the-wrong-nsproxy-usage.patch ptrace-dont-take-tasklist-to-get-set-last_siginfo.patch ptrace-wait_task_zombie-do-not-account-traced-sub-threads.patch wait_task_zombie-do-not-use-thread_group_cputime.patch signals-tracehook_notify_jctl-change.patch utrace-core.patch copy_process-remove-the-unneeded-clear_tsk_thread_flagtif_sigpending.patch elf_core_dump-use-rcu_read_lock-to-access-real_parent.patch shift-ptrace-implies-wuntraced-from-ptrace_do_wait-to-wait_task_stopped.patch introduce-struct-wait_opts-to-simplify-do_wait-pathes.patch do_wait-simplify-retval-tsk_result-notask_error-mess.patch do_wait-kill-the-old-bug_on-use-while_each_thread.patch do_wait-fix-the-theoretical-race-with-stop-trace-cont.patch mm-exitc-reorder-wait_opts-to-remove-padding-on-64-bit-builds.patch kthreads-simplify-the-startup-synchronization.patch kthreads-rework-kthread_stop.patch kthreads-simplify-migration_thread-exit-path.patch pids-clean-up-find_task_by_pid-variants.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html