The patch titled Subject: freezer: do not send a fake signal to a PF_DUMPCORE thread has been removed from the -mm tree. Its filename was freezer-do-not-send-a-fake-signal-to-a-pf_dumpcore-thread.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: freezer: do not send a fake signal to a PF_DUMPCORE thread A coredumping thread can't be frozen anyway but the fake signal sent by freeze_task() can confuse dump_write/wait_for_dump_helpers/etc and interrupt the coredump. We are going to make the do_coredump() paths freezable but the fake TIF_SIGPENDING doesn't help, it only makes sense when we assume that the target can return to user-mode and call get_signal_to_deliver(). Change freeze_task() to check PF_DUMPCORE along with PF_KTHREAD. We need to recheck PF_DUMPCORE under ->siglock to avoid the race with zap_threads() which can set this flag right before we take the lock. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: Mandeep Singh Baines <msb@xxxxxxxxxxxx> Cc: Neil Horman <nhorman@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/freezer.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff -puN kernel/freezer.c~freezer-do-not-send-a-fake-signal-to-a-pf_dumpcore-thread kernel/freezer.c --- a/kernel/freezer.c~freezer-do-not-send-a-fake-signal-to-a-pf_dumpcore-thread +++ a/kernel/freezer.c @@ -85,14 +85,21 @@ bool __refrigerator(bool check_kthr_stop } EXPORT_SYMBOL(__refrigerator); -static void fake_signal_wake_up(struct task_struct *p) +static bool fake_signal_wake_up(struct task_struct *p) { unsigned long flags; + bool ret = false; + + if (p->flags & (PF_KTHREAD | PF_DUMPCORE)) + return ret; if (lock_task_sighand(p, &flags)) { - signal_wake_up(p, 0); + ret = !(p->flags & PF_DUMPCORE); + if (ret) + signal_wake_up(p, 0); unlock_task_sighand(p, &flags); } + return ret; } /** @@ -100,8 +107,8 @@ static void fake_signal_wake_up(struct t * @p: task to send the request to * * If @p is freezing, the freeze request is sent either by sending a fake - * signal (if it's not a kernel thread) or waking it up (if it's a kernel - * thread). + * signal (if it's not a kernel thread or a coredumping thread) or waking + * it up otherwise. * * RETURNS: * %false, if @p is not freezing or already frozen; %true, otherwise @@ -116,9 +123,7 @@ bool freeze_task(struct task_struct *p) return false; } - if (!(p->flags & PF_KTHREAD)) - fake_signal_wake_up(p); - else + if (!fake_signal_wake_up(p)) wake_up_state(p, TASK_INTERRUPTIBLE); spin_unlock_irqrestore(&freezer_lock, flags); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are thinkpad-acpi-kill-hotkey_thread_mutex.patch lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch ptrace-add-ability-to-retrieve-signals-without-removing-from-a-queue-v4.patch selftest-add-a-test-case-for-ptrace_peeksiginfo.patch coredump-only-sigkill-should-interrupt-the-coredumping-task.patch coredump-ensure-that-sigkill-always-kills-the-dumping-thread.patch coredump-sanitize-the-setting-of-signal-group_exit_code.patch coredump-make-wait_for_dump_helpers-freezable.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