The patch titled allow_signal: kill the bogus ->mm check, add a note about CLONE_SIGHAND has been added to the -mm tree. Its filename is allow_signal-kill-the-bogus-mm-check-add-a-note-about-clone_sighand.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: allow_signal: kill the bogus ->mm check, add a note about CLONE_SIGHAND From: Oleg Nesterov <oleg@xxxxxxxxxx> allow_signal() checks ->mm == NULL. Not sure why. Perhaps to make sure current is the kernel thread. But this helper must not be used unless we are the kernel thread, kill this check. Also, document the fact that the CLONE_SIGHAND kthread must not use allow_signal(), unless the caller really wants to change the parent's ->sighand->action as well. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Roland McGrath <roland@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/exit.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff -puN kernel/exit.c~allow_signal-kill-the-bogus-mm-check-add-a-note-about-clone_sighand kernel/exit.c --- a/kernel/exit.c~allow_signal-kill-the-bogus-mm-check-add-a-note-about-clone_sighand +++ a/kernel/exit.c @@ -370,9 +370,8 @@ static void set_special_pids(struct pid } /* - * Let kernel threads use this to say that they - * allow a certain signal (since daemonize() will - * have disabled all of them by default). + * Let kernel threads use this to say that they allow a certain signal. + * Must not be used if kthread was cloned with CLONE_SIGHAND. */ int allow_signal(int sig) { @@ -380,14 +379,14 @@ int allow_signal(int sig) return -EINVAL; spin_lock_irq(¤t->sighand->siglock); + /* This is only needed for daemonize()'ed kthreads */ sigdelset(¤t->blocked, sig); - if (!current->mm) { - /* Kernel threads handle their own signals. - Let the signal code know it'll be handled, so - that they don't get converted to SIGKILL or - just silently dropped */ - current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; - } + /* + * Kernel threads handle their own signals. Let the signal code + * know it'll be handled, so that they don't get converted to + * SIGKILL or just silently dropped. + */ + current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); return 0; _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch rcu_sched_grace_period-kill-the-bogus-flush_signals.patch drivers-staging-epl-do-not-use-clone_sighand-with-allow_signal.patch slow_work_thread-should-do-the-exclusive-wait.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 copy_process-remove-the-unneeded-clear_tsk_thread_flagtif_sigpending.patch elf_core_dump-use-rcu_read_lock-to-access-real_parent.patch kthreads-simplify-the-startup-synchronization.patch kthreads-rework-kthread_stop.patch kthreads-simplify-migration_thread-exit-path.patch signals-split-do_tkill.patch signals-implement-sys_rt_tgsigqueueinfo.patch x86-hookup-sys_rt_tgsigqueueinfo.patch signals-tracehook_notify_jctl-change.patch utrace-core-kill-exclude_xtrace-logic.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