The patch titled kill_pid_info: don't take now unneeded tasklist_lock has been added to the -mm tree. Its filename is kill_pid_info-dont-take-now-unneeded-tasklist_lock.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: kill_pid_info: don't take now unneeded tasklist_lock From: Oleg Nesterov <oleg@xxxxxxxxxx> Previously handle_stop_signal(SIGCONT) could drop ->siglock. That is why kill_pid_info(SIGCONT) takes tasklist_lock to make sure the target task can't go away after unlock. Not needed now. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Cc: Jiri Kosina <jkosina@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/signal.h | 2 -- kernel/signal.c | 7 +------ 2 files changed, 1 insertion(+), 8 deletions(-) diff -puN include/linux/signal.h~kill_pid_info-dont-take-now-unneeded-tasklist_lock include/linux/signal.h --- a/include/linux/signal.h~kill_pid_info-dont-take-now-unneeded-tasklist_lock +++ a/include/linux/signal.h @@ -362,8 +362,6 @@ int unhandled_signal(struct task_struct #define sig_kernel_stop(sig) \ (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK)) -#define sig_needs_tasklist(sig) ((sig) == SIGCONT) - #define sig_user_defined(t, signr) \ (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \ ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN)) diff -puN kernel/signal.c~kill_pid_info-dont-take-now-unneeded-tasklist_lock kernel/signal.c --- a/kernel/signal.c~kill_pid_info-dont-take-now-unneeded-tasklist_lock +++ a/kernel/signal.c @@ -1039,9 +1039,6 @@ int kill_pid_info(int sig, struct siginf struct task_struct *p; rcu_read_lock(); - if (unlikely(sig_needs_tasklist(sig))) - read_lock(&tasklist_lock); - retry: p = pid_task(pid, PIDTYPE_PID); if (p) { @@ -1055,10 +1052,8 @@ retry: */ goto retry; } - - if (unlikely(sig_needs_tasklist(sig))) - read_unlock(&tasklist_lock); rcu_read_unlock(); + return error; } _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are git-hrt.patch kthread-call-wake_up_process-without-the-lock-being-held.patch mmap_region-cleanup-the-final-vma_merge-related-code.patch remove-unused-variable-from-send_signal.patch turn-legacy_queue-macro-into-static-inline-function.patch consolidate-checking-for-ignored-legacy-signals.patch consolidate-checking-for-ignored-legacy-signals-simplify.patch signals-do_signal_stop-use-signal_group_exit.patch signals-do_group_exit-use-signal_group_exit-more-consistently.patch lock_task_sighand-add-rcu-lock-unlock.patch k_getrusage-dont-take-rcu_read_lock.patch do_task_stat-dont-take-rcu_read_lock.patch signals-consolidate-checks-for-whether-or-not-to-ignore-a-signal.patch signals-clean-dequeue_signal-from-excess-checks-and-assignments.patch signals-consolidate-send_sigqueue-and-send_group_sigqueue.patch signals-cleanup-security_task_kill-usage-implementation.patch signals-re-assign-cld_continued-notification-from-the-sender-to-reciever.patch kill_pid_info-dont-take-now-unneeded-tasklist_lock.patch ptrace-introduce-task_detached-helper.patch ptrace-introduce-ptrace_reparented-helper.patch reparent_thread-use-same_thread_group.patch document-de_thread-with-exit_notify-connection.patch workqueues-shrink-cpu_populated_map-when-cpu-dies.patch workqueues-shrink-cpu_populated_map-when-cpu-dies-fix.patch cleanup_workqueue_thread-remove-the-unneeded-cpu-parameter.patch simplify-cpu_hotplug_begin-put_online_cpus.patch redo-locking-of-tty-pgrp.patch resume-tty-on-susp-and-fix-crnl-order-in-n_tty-line-discipline.patch tty_io-fix-remaining-pid-struct-locking.patch tty_io-fix-remaining-pid-struct-locking-small-cleanup.patch procfs-task-exe-symlink.patch procfs-task-exe-symlink-fix.patch procfs-task-exe-symlink-fix-2.patch free_pidmap-turn-it-into-free_pidmapstruct-upid.patch put_pid-make-sure-we-dont-free-the-live-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