The patch titled signals: introduce send_sigkill() helper has been added to the -mm tree. Its filename is signals-introduce-send_sigkill-helper.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: signals: introduce send_sigkill() helper From: Oleg Nesterov <oleg@xxxxxxxxxx> Cleanup, no functional changes. There are a lot of buggy SIGKILL users in kernel. For example, almost every force_sig(SIGKILL) is wrong. force_sig() is not safe, it assumes that the task has the valid ->sighand, and in general it should be used only for synchronous signals. send_sig(SIGKILL, p, 1) or send_xxx(SEND_SIG_FORCED/SEND_SIG_PRIV) is not right too but this is not immediately obvious. The only way to correctly send SIGKILL is send_sig_info(SEND_SIG_NOINFO) but we do not want to use this directly, because we can optimize this case later. For example, zap_pid_ns_processes() allocates sigqueue for each process in namespace, this is unneeded. Introduce the trivial send_sigkill() helper on top of send_sig_info() and change zap_pid_ns_processes() as an example. Note: we need more cleanups here, this is only the first change. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/sched.h | 9 +++++++++ kernel/pid_namespace.c | 8 +------- 2 files changed, 10 insertions(+), 7 deletions(-) diff -puN include/linux/sched.h~signals-introduce-send_sigkill-helper include/linux/sched.h --- a/include/linux/sched.h~signals-introduce-send_sigkill-helper +++ a/include/linux/sched.h @@ -2049,6 +2049,15 @@ static inline int kill_cad_pid(int sig, #define SEND_SIG_PRIV ((struct siginfo *) 1) #define SEND_SIG_FORCED ((struct siginfo *) 2) +static inline int send_sigkill(struct task_struct * p) +{ + /* + * Kills any user-space task, even SIGNAL_UNKILLABLE. + * We use SEND_SIG_NOINFO to make si_fromuser() true. + */ + return send_sig_info(SIGKILL, SEND_SIG_NOINFO, p); +} + /* * True if we are on the alternate signal stack. */ diff -puN kernel/pid_namespace.c~signals-introduce-send_sigkill-helper kernel/pid_namespace.c --- a/kernel/pid_namespace.c~signals-introduce-send_sigkill-helper +++ a/kernel/pid_namespace.c @@ -160,15 +160,9 @@ void zap_pid_ns_processes(struct pid_nam nr = next_pidmap(pid_ns, 1); while (nr > 0) { rcu_read_lock(); - - /* - * Any nested-container's init processes won't ignore the - * SEND_SIG_NOINFO signal, see send_signal()->si_fromuser(). - */ task = pid_task(find_vpid(nr), PIDTYPE_PID); if (task) - send_sig_info(SIGKILL, SEND_SIG_NOINFO, task); - + send_sigkill(task); rcu_read_unlock(); nr = next_pidmap(pid_ns, nr); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch oom-check-pf_kthread-instead-of-mm-to-skip-kthreads.patch oom-pf_exiting-check-should-take-mm-into-account.patch oom-introduce-find_lock_task_mm-to-fix-mm-false-positives.patch oom-dump_tasks-use-find_lock_task_mm-too.patch oom-improve-commentary-in-dump_tasks.patch oom-dump_tasks-use-find_lock_task_mm-too-dump_tasks-use-find_lock_task_mm-too-fix.patch oom-sacrifice-child-with-highest-badness-score-for-parent-protect-dereferencing-of-tasks-comm.patch oom-sacrifice-child-with-highest-badness-score-for-parent-fix.patch oom-select-task-from-tasklist-for-mempolicy-ooms-add-has_intersects_mems_allowed-uma-variant.patch oom-select-task-from-tasklist-for-mempolicy-ooms-introduce-find_lock_task_mm-to-fix-mm-false-positives-fix.patch sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path.patch signals-introduce-send_sigkill-helper.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