The patch titled
coredump: kill mm->core_done
has been added to the -mm tree. Its filename is
coredump-kill-mm-core_done.patch
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out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: coredump: kill mm->core_done
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.
This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion). Also, with this change we can
decouple exit_mm() from the coredumping code.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 24 ++++++++++++++++++++++--
include/linux/mm_types.h | 4 +---
kernel/exit.c | 8 +++++++-
3 files changed, 30 insertions(+), 6 deletions(-)
diff -puN fs/exec.c~coredump-kill-mm-core_done fs/exec.c
--- a/fs/exec.c~coredump-kill-mm-core_done
+++ a/fs/exec.c
@@ -1603,7 +1603,6 @@ static int coredump_wait(int exit_code)
struct completion *vfork_done;
int core_waiters;
- init_completion(&mm->core_done);
init_completion(&core_state.startup);
core_waiters = zap_threads(tsk, mm, &core_state, exit_code);
up_write(&mm->mmap_sem);
@@ -1628,6 +1627,27 @@ fail:
return core_waiters;
}
+static void coredump_finish(struct mm_struct *mm)
+{
+ struct core_thread *curr, *next;
+ struct task_struct *task;
+
+ next = mm->core_state->dumper.next;
+ while ((curr = next) != NULL) {
+ next = curr->next;
+ task = curr->task;
+ /*
+ * see exit_mm(), curr->task must not see
+ * ->task == NULL before we read ->next.
+ */
+ smp_mb();
+ curr->task = NULL;
+ wake_up_process(task);
+ }
+
+ mm->core_state = NULL;
+}
+
/*
* set_dumpable converts traditional three-value dumpable to two flags and
* stores them into mm->flags. It modifies lower two bits of mm->flags, but
@@ -1811,7 +1831,7 @@ fail_unlock:
argv_free(helper_argv);
current->fsuid = fsuid;
- complete_all(&mm->core_done);
+ coredump_finish(mm);
fail:
return retval;
}
diff -puN include/linux/mm_types.h~coredump-kill-mm-core_done include/linux/mm_types.h
--- a/include/linux/mm_types.h~coredump-kill-mm-core_done
+++ a/include/linux/mm_types.h
@@ -228,9 +228,7 @@ struct mm_struct {
unsigned long flags; /* Must use atomic bitops to access the bits */
- /* coredumping support */
- struct core_state *core_state;
- struct completion core_done;
+ struct core_state *core_state; /* coredumping support */
/* aio bits */
rwlock_t ioctx_list_lock; /* aio lock */
diff -puN kernel/exit.c~coredump-kill-mm-core_done kernel/exit.c
--- a/kernel/exit.c~coredump-kill-mm-core_done
+++ a/kernel/exit.c
@@ -669,7 +669,13 @@ static void exit_mm(struct task_struct *
if (atomic_dec_and_test(&mm->core_state->nr_threads))
complete(&mm->core_state->startup);
- wait_for_completion(&mm->core_done);
+ for (;;) {
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+ if (!self.task) /* see coredump_finish() */
+ break;
+ schedule();
+ }
+ __set_task_state(tsk, TASK_RUNNING);
down_read(&mm->mmap_sem);
}
atomic_inc(&mm->mm_count);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
migrate_timers-add-comment-use-spinlock_irq.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup.patch
posix-timers-timer_delete-remove-the-bogus-it_process-=-null-check.patch
posix-timers-release_posix_timer-kill-the-bogus-put_task_struct-it_process.patch
signals-collect_signal-remove-the-unneeded-sigismember-check.patch
signals-collect_signal-simplify-the-still_pending-logic.patch
signals-change-collect_signal-to-return-void.patch
__exit_signal-dont-take-rcu-lock.patch
signals-dequeue_signal-dont-check-signal_group_exit-when-setting-signal_stop_dequeued.patch
signals-do_signal_stop-kill-the-signal_unkillable-check.patch
coredump-zap_threads-comments-use-while_each_thread.patch
signals-make-siginfo_t-si_utime-si_sstime-report-times-in-user_hz-not-hz.patch
kernel-signalc-change-vars-pid-and-tgid-types-to-pid_t.patch
include-asm-ptraceh-userspace-headers-cleanup.patch
ptrace-give-more-respect-to-sigkill.patch
ptrace-simplify-ptrace_stop-sigkill_pending-path.patch
introduce-pf_kthread-flag.patch
kill-pf_borrowed_mm-in-favour-of-pf_kthread.patch
coredump-zap_threads-must-skip-kernel-threads.patch
coredump-elf_core_dump-skip-kernel-threads.patch
coredump-turn-mm-core_startup_done-into-the-pointer-to-struct-core_state.patch
coredump-move-mm-core_waiters-into-struct-core_state.patch
coredump-simplify-core_state-nr_threads-calculation.patch
coredump-turn-core_state-nr_threads-into-atomic_t.patch
coredump-kill-mm-core_done.patch
workqueues-insert_work-use-list_head-instead-of-int-tail.patch
workqueues-implement-flush_work.patch
workqueues-schedule_on_each_cpu-use-flush_work.patch
workqueues-make-get_online_cpus-useable-for-work-func.patch
workqueues-make-get_online_cpus-useable-for-work-func-fix.patch
s390-topology-dont-use-kthread-for-arch_reinit_sched_domains.patch
workqueues-lockdep-annotations-for-flush_work.patch
workqueues-queue_work-can-use-queue_work_on.patch
workqueues-schedule_on_each_cpu-can-use-schedule_work_on.patch
pidns-remove-now-unused-kill_proc-function.patch
pidns-remove-now-unused-find_pid-function.patch
pidns-remove-find_task_by_pid-unused-for-a-long-time.patch
distinct-tgid-tid-i-o-statistics.patch
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