The patch titled
coredump: construct the list of coredumping threads at startup time
has been removed from the -mm tree. Its filename was
coredump-construct-the-list-of-coredumping-threads-at-startup-time.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: coredump: construct the list of coredumping threads at startup time
From: Oleg Nesterov <oleg@xxxxxxxxxx>
binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.
With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.
This allows us to do further changes:
- simplify ->core_dump()
- change exit_mm() to clear ->mm first, then wait for ->core_done.
this makes the coredumping process visible to oom_kill
- kill mm->core_done
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 2 ++
include/linux/mm_types.h | 6 ++++++
kernel/exit.c | 15 ++++++++++++---
3 files changed, 20 insertions(+), 3 deletions(-)
diff -puN fs/exec.c~coredump-construct-the-list-of-coredumping-threads-at-startup-time fs/exec.c
--- a/fs/exec.c~coredump-construct-the-list-of-coredumping-threads-at-startup-time
+++ a/fs/exec.c
@@ -1604,6 +1604,8 @@ static int coredump_wait(int exit_code,
init_completion(&mm->core_done);
init_completion(&core_state->startup);
+ core_state->dumper.task = tsk;
+ core_state->dumper.next = NULL;
core_waiters = zap_threads(tsk, mm, core_state, exit_code);
up_write(&mm->mmap_sem);
diff -puN include/linux/mm_types.h~coredump-construct-the-list-of-coredumping-threads-at-startup-time include/linux/mm_types.h
--- a/include/linux/mm_types.h~coredump-construct-the-list-of-coredumping-threads-at-startup-time
+++ a/include/linux/mm_types.h
@@ -159,8 +159,14 @@ struct vm_area_struct {
#endif
};
+struct core_thread {
+ struct task_struct *task;
+ struct core_thread *next;
+};
+
struct core_state {
atomic_t nr_threads;
+ struct core_thread dumper;
struct completion startup;
};
diff -puN kernel/exit.c~coredump-construct-the-list-of-coredumping-threads-at-startup-time kernel/exit.c
--- a/kernel/exit.c~coredump-construct-the-list-of-coredumping-threads-at-startup-time
+++ a/kernel/exit.c
@@ -664,6 +664,7 @@ assign_new_owner:
static void exit_mm(struct task_struct * tsk)
{
struct mm_struct *mm = tsk->mm;
+ struct core_state *core_state;
mm_release(tsk, mm);
if (!mm)
@@ -676,11 +677,19 @@ static void exit_mm(struct task_struct *
* group with ->mm != NULL.
*/
down_read(&mm->mmap_sem);
- if (mm->core_state) {
+ core_state = mm->core_state;
+ if (core_state) {
+ struct core_thread self;
up_read(&mm->mmap_sem);
- if (atomic_dec_and_test(&mm->core_state->nr_threads))
- complete(&mm->core_state->startup);
+ self.task = tsk;
+ self.next = xchg(&core_state->dumper.next, &self);
+ /*
+ * Implies mb(), the result of xchg() must be visible
+ * to core_state->dumper.
+ */
+ if (atomic_dec_and_test(&core_state->nr_threads))
+ complete(&core_state->startup);
wait_for_completion(&mm->core_done);
down_read(&mm->mmap_sem);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
migrate_timers-add-comment-use-spinlock_irq.patch
tracehook-add-linux-tracehookh.patch
tracehook-exec.patch
tracehook-unexport-ptrace_notify.patch
tracehook-exit.patch
tracehook-clone.patch
tracehook-vfork-done.patch
tracehook-release_task.patch
tracehook-tracehook_tracer_task.patch
tracehook-tracehook_expect_breakpoints.patch
tracehook-tracehook_signal_handler.patch
tracehook-tracehook_consider_ignored_signal.patch
tracehook-tracehook_consider_fatal_signal.patch
tracehook-syscall.patch
tracehook-get_signal_to_deliver.patch
tracehook-job-control.patch
tracehook-death.patch
tracehook-force-signal_pending.patch
tracehook-tif_notify_resume.patch
tracehook-asm-syscallh.patch
tracehook-config_have_arch_tracehook.patch
tracehook-wait_task_inactive.patch
task_current_syscall.patch
proc-pid-syscall.patch
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