From: Xie Yongji <xieyongji@bytedance.com> To: mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com, sgarzare@redhat.com, parav@nvidia.com, hch@infradead.org, christian.brauner@canonical.com, rdunlap@infradead.org, willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com, dan.carpenter@oracle.com, joro@8bytes.org Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 03/12] eventfd: Increase the recursion depth of eventfd_signal() Date: Mon, 17 May 2021 17:55:04 +0800 [thread overview] Message-ID: <20210517095513.850-4-xieyongji@bytedance.com> (raw) In-Reply-To: <20210517095513.850-1-xieyongji@bytedance.com> Increase the recursion depth of eventfd_signal() to 1. This is the maximum recursion depth we have found so far, which can be triggered with the following call chain: kvm_io_bus_write [kvm] --> ioeventfd_write [kvm] --> eventfd_signal [eventfd] --> vhost_poll_wakeup [vhost] --> vduse_vdpa_kick_vq [vduse] --> eventfd_signal [eventfd] Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Acked-by: Jason Wang <jasowang@redhat.com> --- fs/eventfd.c | 2 +- include/linux/eventfd.h | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/eventfd.c b/fs/eventfd.c index e265b6dd4f34..cc7cd1dbedd3 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -71,7 +71,7 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) * it returns true, the eventfd_signal() call should be deferred to a * safe context. */ - if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count))) + if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH)) return 0; spin_lock_irqsave(&ctx->wqh.lock, flags); diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index fa0a524baed0..886d99cd38ef 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -29,6 +29,9 @@ #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) +/* Maximum recursion depth */ +#define EFD_WAKE_DEPTH 1 + struct eventfd_ctx; struct file; @@ -47,7 +50,7 @@ DECLARE_PER_CPU(int, eventfd_wake_count); static inline bool eventfd_signal_count(void) { - return this_cpu_read(eventfd_wake_count); + return this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH; } #else /* CONFIG_EVENTFD */ -- 2.11.0
WARNING: multiple messages have this Message-ID (diff)
From: Xie Yongji <xieyongji@bytedance.com> To: mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com, sgarzare@redhat.com, parav@nvidia.com, hch@infradead.org, christian.brauner@canonical.com, rdunlap@infradead.org, willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com, dan.carpenter@oracle.com, joro@8bytes.org Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v7 03/12] eventfd: Increase the recursion depth of eventfd_signal() Date: Mon, 17 May 2021 17:55:04 +0800 [thread overview] Message-ID: <20210517095513.850-4-xieyongji@bytedance.com> (raw) In-Reply-To: <20210517095513.850-1-xieyongji@bytedance.com> Increase the recursion depth of eventfd_signal() to 1. This is the maximum recursion depth we have found so far, which can be triggered with the following call chain: kvm_io_bus_write [kvm] --> ioeventfd_write [kvm] --> eventfd_signal [eventfd] --> vhost_poll_wakeup [vhost] --> vduse_vdpa_kick_vq [vduse] --> eventfd_signal [eventfd] Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Acked-by: Jason Wang <jasowang@redhat.com> --- fs/eventfd.c | 2 +- include/linux/eventfd.h | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/eventfd.c b/fs/eventfd.c index e265b6dd4f34..cc7cd1dbedd3 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -71,7 +71,7 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) * it returns true, the eventfd_signal() call should be deferred to a * safe context. */ - if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count))) + if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH)) return 0; spin_lock_irqsave(&ctx->wqh.lock, flags); diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index fa0a524baed0..886d99cd38ef 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -29,6 +29,9 @@ #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) +/* Maximum recursion depth */ +#define EFD_WAKE_DEPTH 1 + struct eventfd_ctx; struct file; @@ -47,7 +50,7 @@ DECLARE_PER_CPU(int, eventfd_wake_count); static inline bool eventfd_signal_count(void) { - return this_cpu_read(eventfd_wake_count); + return this_cpu_read(eventfd_wake_count) > EFD_WAKE_DEPTH; } #else /* CONFIG_EVENTFD */ -- 2.11.0 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-05-17 9:56 UTC|newest] Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-17 9:55 [PATCH v7 00/12] Introduce VDUSE - vDPA Device in Userspace Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 01/12] iova: Export alloc_iova_fast() Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-26 2:36 ` Jason Wang 2021-05-26 2:36 ` Jason Wang 2021-05-26 2:36 ` Jason Wang 2021-05-26 2:43 ` Yongji Xie 2021-05-26 2:43 ` Yongji Xie 2021-05-17 9:55 ` [PATCH v7 02/12] file: Export receive_fd() to modules Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-20 6:18 ` Al Viro 2021-05-20 6:18 ` Al Viro 2021-05-20 6:18 ` Al Viro 2021-05-20 6:32 ` Yongji Xie 2021-05-20 6:32 ` Yongji Xie 2021-05-17 9:55 ` Xie Yongji [this message] 2021-05-17 9:55 ` [PATCH v7 03/12] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji 2021-05-17 9:55 ` [PATCH v7 04/12] virtio-blk: Add validation for block size in config space Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-19 13:39 ` Yongji Xie 2021-05-19 13:39 ` Yongji Xie 2021-05-19 14:42 ` Dan Carpenter 2021-05-19 14:42 ` Dan Carpenter 2021-05-19 14:42 ` Dan Carpenter 2021-05-20 5:25 ` Yongji Xie 2021-05-20 5:25 ` Yongji Xie 2021-05-20 5:43 ` Michael S. Tsirkin 2021-05-20 5:43 ` Michael S. Tsirkin 2021-05-20 5:43 ` Michael S. Tsirkin 2021-05-20 7:08 ` Yongji Xie 2021-05-20 7:08 ` Yongji Xie 2021-05-17 9:55 ` [PATCH v7 05/12] virtio_scsi: Add validation for residual bytes from response Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-26 2:41 ` Jason Wang 2021-05-26 2:41 ` Jason Wang 2021-05-26 2:41 ` Jason Wang 2021-05-17 9:55 ` [PATCH v7 06/12] vhost-iotlb: Add an opaque pointer for vhost IOTLB Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 07/12] vdpa: Add an opaque pointer for vdpa_config_ops.dma_map() Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 08/12] vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap() Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 09/12] vdpa: Support transferring virtual addressing during DMA mapping Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 10/12] vduse: Implement an MMU-based IOMMU driver Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-17 9:55 ` [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-20 6:28 ` Al Viro 2021-05-20 6:28 ` Al Viro 2021-05-20 6:28 ` Al Viro 2021-05-20 7:03 ` Yongji Xie 2021-05-20 7:03 ` Yongji Xie 2021-05-27 4:12 ` Jason Wang 2021-05-27 4:12 ` Jason Wang 2021-05-27 4:12 ` Jason Wang 2021-05-27 4:57 ` Yongji Xie 2021-05-27 4:57 ` Yongji Xie 2021-05-27 5:00 ` Jason Wang 2021-05-27 5:00 ` Jason Wang 2021-05-27 5:00 ` Jason Wang 2021-05-27 5:08 ` Yongji Xie 2021-05-27 5:08 ` Yongji Xie 2021-05-27 5:40 ` Jason Wang 2021-05-27 5:40 ` Jason Wang 2021-05-27 5:40 ` Jason Wang 2021-05-27 7:34 ` Yongji Xie 2021-05-27 7:34 ` Yongji Xie 2021-05-27 8:41 ` Jason Wang 2021-05-27 8:41 ` Jason Wang 2021-05-27 8:41 ` Jason Wang 2021-05-27 8:43 ` Jason Wang 2021-05-27 8:43 ` Jason Wang 2021-05-27 8:43 ` Jason Wang 2021-05-27 10:14 ` Yongji Xie 2021-05-27 10:14 ` Yongji Xie 2021-05-28 1:33 ` Jason Wang 2021-05-28 1:33 ` Jason Wang 2021-05-28 1:33 ` Jason Wang 2021-05-28 3:54 ` Yongji Xie 2021-05-28 3:54 ` Yongji Xie 2021-05-28 6:38 ` Jason Wang 2021-05-28 6:38 ` Jason Wang 2021-05-28 6:38 ` Jason Wang 2021-05-27 13:17 ` Yongji Xie 2021-05-27 13:17 ` Yongji Xie 2021-05-28 2:31 ` Jason Wang 2021-05-28 2:31 ` Jason Wang 2021-05-28 2:31 ` Jason Wang 2021-05-31 4:27 ` Yongji Xie 2021-05-31 4:27 ` Yongji Xie 2021-05-31 4:38 ` Jason Wang 2021-05-31 4:38 ` Jason Wang 2021-05-31 4:38 ` Jason Wang 2021-05-31 6:24 ` Yongji Xie 2021-05-31 6:24 ` Yongji Xie 2021-05-31 4:56 ` Greg KH 2021-05-31 4:56 ` Greg KH 2021-05-31 4:56 ` Greg KH 2021-05-31 6:19 ` Yongji Xie 2021-05-31 6:19 ` Yongji Xie 2021-05-31 6:32 ` Greg KH 2021-05-31 6:32 ` Greg KH 2021-05-31 6:32 ` Greg KH 2021-05-31 7:13 ` Yongji Xie 2021-05-31 7:13 ` Yongji Xie 2021-05-17 9:55 ` [PATCH v7 12/12] Documentation: Add documentation for VDUSE Xie Yongji 2021-05-17 9:55 ` Xie Yongji 2021-05-20 6:06 ` [PATCH v7 00/12] Introduce VDUSE - vDPA Device in Userspace Michael S. Tsirkin 2021-05-20 6:06 ` Michael S. Tsirkin 2021-05-20 6:06 ` Michael S. Tsirkin 2021-05-20 9:06 ` Yongji Xie 2021-05-20 9:06 ` Yongji Xie 2021-05-25 6:40 ` Jason Wang 2021-05-25 6:40 ` Jason Wang 2021-05-25 6:40 ` Jason Wang 2021-05-25 6:48 ` Michael S. Tsirkin 2021-05-25 6:48 ` Michael S. Tsirkin 2021-05-25 6:48 ` Michael S. Tsirkin 2021-05-25 7:11 ` Jason Wang 2021-05-25 7:11 ` Jason Wang 2021-05-25 7:11 ` Jason Wang
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