The patch titled fix the "remove task_ppid_nr_ns" commit has been added to the -mm tree. Its filename is fix-the-remove-task_ppid_nr_ns-commit.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://www.zip.com.au/~akpm/linux/patches/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: fix the "remove task_ppid_nr_ns" commit From: Oleg Nesterov <oleg@xxxxxxxxxx> The commit 84427eaef1fb91704c7112bdb598c810003b99f3 (remove task_ppid_nr_ns) moves the task_tgid_nr_ns(task->real_parent) outside of lock_task_sighand(). This is wrong, ->real_parent could be freed/reused. Both ->parent/real_parent point to nothnig after __exit_signal() because we remove the child from ->children list, and thus the child can't be reparented when its parent exits. rcu_read_lock() protects ->parent/real_parent, but _only_ if we know it was valid before we take rcu lock. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Roland McGrath <roland@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/array.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN fs/proc/array.c~fix-the-remove-task_ppid_nr_ns-commit fs/proc/array.c --- a/fs/proc/array.c~fix-the-remove-task_ppid_nr_ns-commit +++ a/fs/proc/array.c @@ -426,7 +426,6 @@ static int do_task_stat(struct seq_file cgtime = gtime = cputime_zero; rcu_read_lock(); - ppid = task_tgid_nr_ns(task->real_parent, ns); if (lock_task_sighand(task, &flags)) { struct signal_struct *sig = task->signal; @@ -465,6 +464,7 @@ static int do_task_stat(struct seq_file } sid = task_session_nr_ns(task, ns); + ppid = task_tgid_nr_ns(task->real_parent, ns); pgid = task_pgrp_nr_ns(task, ns); unlock_task_sighand(task, &flags); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are remove-task_ppid_nr_ns.patch fix-the-remove-task_ppid_nr_ns-commit.patch __group_complete_signal-fix-coredump-with-group-stop-race.patch remove-handle_group_stop-in-favor-of-do_signal_stop.patch exec-rework-the-group-exit-and-fix-the-race-with-kill.patch use-__set_task_state-for-traced-stopped-tasks.patch add-task_wakekill.patch do_wait-remove-one-else-if-branch.patch proc-implement-proc_single_file_operations.patch proc-rewrite-do_task_stat-to-correctly-handle-pid-namespaces.patch proc-seqfile-convert-proc_pid_statm.patch proc-proper-pidns-handling-for-proc-self.patch proc-fix-the-threaded-proc-self.patch proc-fix-openless-usage-due-to-proc_fops-flip.patch proc-fix-openless-usage-due-to-proc_fops-flip-checkpatch-fixes.patch kill-pt_attached.patch kill-my_ptrace_child.patch ptrace_check_attach-remove-unneeded-signal-=-null-check.patch ptrace_stop-fix-the-race-with-ptrace-detachattach.patch wait_task_stopped-simplify-and-fix-races-with-sigcont-sigkill-untrace.patch do_wait-factor-out-retval-=-0-checks.patch ptrace_stop-fix-racy-nonstop_code-setting.patch wait_task_stopped-remove-unneeded-delay_group_leader-check.patch do_wait-cleanup-delay_group_leader-usage.patch do_wait-fix-security-checks.patch do_wait-fix-security-checks-fix.patch wait_task_continued-zombie-dont-use-task_pid_nr_ns-lockless.patch wait_task_zombie-remove-exit_state-exit_signal-checks-for-wnowait.patch sys_setpgid-simplify-pid-ns-interaction.patch fix-setsid-for-sub-namespace-sbin-init.patch teach-set_special_pids-to-use-struct-pid.patch move-daemonized-kernel-threads-into-the-swappers-session.patch start-the-global-sbin-init-with-00-special-pids.patch fix-group-stop-with-exit-race.patch sys_setsid-remove-now-unneeded-session-=-1-check.patch move-the-related-code-from-exit_notify-to-exit_signals.patch pid-sys_wait-fixes-v2.patch pid-extend-fix-pid_vnr.patch sys_getsid-dont-use-nsproxy-directly.patch pid-fix-mips-irix-emulation-pid-usage.patch pid-fix-mips-irix-emulation-pid-usage-fix.patch pid-fix-solaris_procids.patch uglify-kill_pid_info-to-fix-kill-vs-exec-race.patch uglify-while_each_pid_task-to-make-sure-we-dont-count-the-execing-pricess-twice.patch itimer_real-convert-to-use-struct-pid.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