The patch titled exit: avoid sig->count in __exit_signal() to detect the group-dead case has been added to the -mm tree. Its filename is exit-avoid-sig-count-in-__exit_signal-to-detect-the-group-dead-case.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: exit: avoid sig->count in __exit_signal() to detect the group-dead case From: Oleg Nesterov <oleg@xxxxxxxxxx> Change __exit_signal() to check thread_group_leader() instead of atomic_dec_and_test(&sig->count). This must be equivalent, the group leader must be released only after all other threads have exited and passed __exit_signal(). Henceforth sig->count is not actually used, except in fs/proc for get_nr_threads/etc. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Roland McGrath <roland@xxxxxxxxxx> Cc: Veaceslav Falico <vfalico@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/exit.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff -puN kernel/exit.c~exit-avoid-sig-count-in-__exit_signal-to-detect-the-group-dead-case kernel/exit.c --- a/kernel/exit.c~exit-avoid-sig-count-in-__exit_signal-to-detect-the-group-dead-case +++ a/kernel/exit.c @@ -89,11 +89,12 @@ static void __exit_signal(struct task_st rcu_read_lock_held() || lockdep_tasklist_lock_is_held()); spin_lock(&sighand->siglock); + atomic_dec(&sig->count); posix_cpu_timers_exit(tsk); - if (atomic_dec_and_test(&sig->count)) + if (thread_group_leader(tsk)) { posix_cpu_timers_exit_group(tsk); - else { + } else { /* * If there is any task waiting for the group exit * then notify it: _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch posix-cpu-timers-reset-expire-cache-when-no-timer-is-running.patch cpu-timers-simplify-rlimit_cpu-handling.patch cpu-timers-cleanup-arm_timer.patch cpu-timers-return-correct-previous-timer-reload-value.patch cpu-timers-change-sigev_none-timer-implementation.patch cpu-timers-assure-to-not-iterate-over-all-threads-in-fastpath_timer_check.patch cpu-timers-optimize-run_posix_cpu_timers.patch proc-cleanup-remove-unused-assignments.patch kmod-add-init-function-to-usermodehelper.patch exec-replace-call_usermodehelper_pipe-with-use-of-umh-init-function-and-resolve-limit.patch umh-creds-convert-call_usermodehelper_keys-to-use-subprocess_info-init.patch umh-creds-kill-subprocess_info-cred-logic.patch call_usermodehelper-no-need-to-unblock-signals.patch wait_for_helper-sigchld-from-user-space-can-lead-to-use-after-free.patch call_usermodehelper-simplify-fix-umh_no_wait-case.patch call_usermodehelper-umh_wait_exec-ignores-kernel_thread-failure.patch coredump-factor-out-the-not-ispipe-file-checks.patch coredump-cleanup-ispipe-code.patch coredump-factor-out-put_cred-calls.patch coredump-shift-down_writemmap_sem-into-coredump_wait.patch exit-exit_notify-can-trust-signal-notify_count-0.patch exit-change-zap_other_threads-to-count-sub-threads.patch exit-avoid-sig-count-in-de_thread-__exit_signal-synchronization.patch exit-avoid-sig-count-in-__exit_signal-to-detect-the-group-dead-case.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