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Violators will be prosecuted for from ; Tue, 24 Jan 2017 13:53:05 -0000 From: Mike Rapoport Subject: [RFC PATCH 3/5] userfaultfd: non-cooperative: add event for exit() notification Date: Tue, 24 Jan 2017 15:52:01 +0200 In-Reply-To: <1485265923-20256-1-git-send-email-rppt@linux.vnet.ibm.com> References: <1485265923-20256-1-git-send-email-rppt@linux.vnet.ibm.com> Message-Id: <1485265923-20256-4-git-send-email-rppt@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Linux-MM Cc: Andrea Arcangeli , Andrew Morton , "Dr. David Alan Gilbert" , Hillf Danton , Mike Kravetz , Pavel Emelyanov , LKML , Mike Rapoport Allow userfaultfd monitor track termination of the processes that have memory backed by the uffd. Signed-off-by: Mike Rapoport --- 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 --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 651d6d8..839ffd5 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -774,6 +774,30 @@ void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf) } } +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 --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index a40be5d..0468548 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -72,6 +72,8 @@ extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, 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_complete(struct mm_struct *mm, struct list_head *uf) { } + +static inline void userfaultfd_exit(struct mm_struct *mm) +{ +} + #endif /* CONFIG_USERFAULTFD */ #endif /* _LINUX_USERFAULTFD_K_H */ diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 3b05953..c055947 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/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 --git a/kernel/exit.c b/kernel/exit.c index 16c6077..c11bf9d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -55,6 +55,7 @@ #include #include #include +#include #include #include @@ -547,6 +548,7 @@ static void exit_mm(void) enter_lazy_tlb(mm, current); task_unlock(current); mm_update_next_owner(mm); + userfaultfd_exit(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) exit_oom_victim(); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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