The patch titled
Subject: userfaultfd: non-cooperative: add event for exit() notification
has been added to the -mm tree. Its filename is
userfaultfd-non-cooperative-add-event-for-exit-notification.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-non-cooperative-add-event-for-exit-notification.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-non-cooperative-add-event-for-exit-notification.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Subject: userfaultfd: non-cooperative: add event for exit() notification
Allow userfaultfd monitor track termination of the processes that have
memory backed by the uffd.
Link: http://lkml.kernel.org/r/1485542673-24387-4-git-send-email-rppt@xxxxxxxxxxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 24 ++++++++++++++++++++++++
include/linux/userfaultfd_k.h | 7 +++++++
include/uapi/linux/userfaultfd.h | 5 ++++-
kernel/exit.c | 2 ++
4 files changed, 37 insertions(+), 1 deletion(-)
diff -puN fs/userfaultfd.c~userfaultfd-non-cooperative-add-event-for-exit-notification fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-non-cooperative-add-event-for-exit-notification
+++ a/fs/userfaultfd.c
@@ -774,6 +774,30 @@ void userfaultfd_unmap_complete(struct m
}
}
+void userfaultfd_exit(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma = mm->mmap;
+
+ while (vma) {
+ struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+ if (ctx && (ctx->features & UFFD_FEATURE_EVENT_EXIT)) {
+ struct userfaultfd_wait_queue ewq;
+
+ userfaultfd_ctx_get(ctx);
+
+ msg_init(&ewq.msg);
+ ewq.msg.event = UFFD_EVENT_EXIT;
+
+ userfaultfd_event_wait_completion(ctx, &ewq);
+
+ ctx->features &= ~UFFD_FEATURE_EVENT_EXIT;
+ }
+
+ vma = vma->vm_next;
+ }
+}
+
static int userfaultfd_release(struct inode *inode, struct file *file)
{
struct userfaultfd_ctx *ctx = file->private_data;
diff -puN include/linux/userfaultfd_k.h~userfaultfd-non-cooperative-add-event-for-exit-notification include/linux/userfaultfd_k.h
--- a/include/linux/userfaultfd_k.h~userfaultfd-non-cooperative-add-event-for-exit-notification
+++ a/include/linux/userfaultfd_k.h
@@ -72,6 +72,8 @@ extern int userfaultfd_unmap_prep(struct
extern void userfaultfd_unmap_complete(struct mm_struct *mm,
struct list_head *uf);
+extern void userfaultfd_exit(struct mm_struct *mm);
+
#else /* CONFIG_USERFAULTFD */
/* mm helpers */
@@ -136,6 +138,11 @@ static inline void userfaultfd_unmap_com
struct list_head *uf)
{
}
+
+static inline void userfaultfd_exit(struct mm_struct *mm)
+{
+}
+
#endif /* CONFIG_USERFAULTFD */
#endif /* _LINUX_USERFAULTFD_K_H */
diff -puN include/uapi/linux/userfaultfd.h~userfaultfd-non-cooperative-add-event-for-exit-notification include/uapi/linux/userfaultfd.h
--- a/include/uapi/linux/userfaultfd.h~userfaultfd-non-cooperative-add-event-for-exit-notification
+++ a/include/uapi/linux/userfaultfd.h
@@ -18,7 +18,8 @@
* means the userland is reading).
*/
#define UFFD_API ((__u64)0xAA)
-#define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_FORK | \
+#define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_EXIT | \
+ UFFD_FEATURE_EVENT_FORK | \
UFFD_FEATURE_EVENT_REMAP | \
UFFD_FEATURE_EVENT_REMOVE | \
UFFD_FEATURE_EVENT_UNMAP | \
@@ -112,6 +113,7 @@ struct uffd_msg {
#define UFFD_EVENT_REMAP 0x14
#define UFFD_EVENT_REMOVE 0x15
#define UFFD_EVENT_UNMAP 0x16
+#define UFFD_EVENT_EXIT 0x17
/* flags for UFFD_EVENT_PAGEFAULT */
#define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */
@@ -161,6 +163,7 @@ struct uffdio_api {
#define UFFD_FEATURE_MISSING_HUGETLBFS (1<<4)
#define UFFD_FEATURE_MISSING_SHMEM (1<<5)
#define UFFD_FEATURE_EVENT_UNMAP (1<<6)
+#define UFFD_FEATURE_EVENT_EXIT (1<<7)
__u64 features;
__u64 ioctls;
diff -puN kernel/exit.c~userfaultfd-non-cooperative-add-event-for-exit-notification kernel/exit.c
--- a/kernel/exit.c~userfaultfd-non-cooperative-add-event-for-exit-notification
+++ a/kernel/exit.c
@@ -46,6 +46,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/tracehook.h>
#include <linux/fs_struct.h>
+#include <linux/userfaultfd_k.h>
#include <linux/init_task.h>
#include <linux/perf_event.h>
#include <trace/events/sched.h>
@@ -518,6 +519,7 @@ static void exit_mm(struct task_struct *
enter_lazy_tlb(mm, current);
task_unlock(tsk);
mm_update_next_owner(mm);
+ userfaultfd_exit(mm);
mmput(mm);
if (test_thread_flag(TIF_MEMDIE))
exit_oom_victim();
_
Patches currently in -mm which might be from rppt@xxxxxxxxxxxxxxxxxx are
userfaultfd-non-cooperative-dup_userfaultfd-use-mm_count-instead-of-mm_users.patch
userfaultfd-introduce-vma_can_userfault.patch
userfaultfd-shmem-add-shmem_mcopy_atomic_pte-for-userfaultfd-support.patch
userfaultfd-shmem-introduce-vma_is_shmem.patch
userfaultfd-shmem-use-shmem_mcopy_atomic_pte-for-shared-memory.patch
userfaultfd-shmem-add-userfaultfd-hook-for-shared-memory-faults.patch
userfaultfd-shmem-allow-registration-of-shared-memory-ranges.patch
userfaultfd-shmem-add-userfaultfd_shmem-test.patch
userfaultfd-non-cooperative-selftest-introduce-userfaultfd_open.patch
userfaultfd-non-cooperative-selftest-add-ufd-parameter-to-copy_page.patch
userfaultfd-non-cooperative-selftest-add-test-for-fork-madvdontneed-and-remap-events.patch
userfaultfd-non-cooperative-rename-event_madvdontneed-to-event_remove.patch
userfaultfd-non-cooperative-add-madvise-event-for-madv_remove-request.patch
userfaultfd-non-cooperative-selftest-enable-remove-event-test-for-shmem.patch
mm-call-vm_munmap-in-munmap-syscall-instead-of-using-open-coded-version.patch
userfaultfd-non-cooperative-add-event-for-memory-unmaps.patch
userfaultfd-non-cooperative-add-event-for-exit-notification.patch
userfaultfd-mcopy_atomic-return-enoent-when-no-compatible-vma-found.patch
userfaultfd_copy-return-enospc-in-case-mm-has-gone.patch
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