NET_DMA violates the expectation of the dma-mapping api by allowing the cpu to touch receive buffer memory while dma is active. If this activity triggers a copy-on-write event the application may see missing data as the dma completes to the old mapping.
[PATCH 1/3] net_dma: mark broken Detail the failure and provide a small one-liner for -stable [PATCH 2/3] net_dma: remove Mark the tcp_dma_copybreak sysctl as removed and remove the rest of the implementation [PATCH 3/3] dma debug: flag copy-on-write events to pages undergoing dma Extend dma-debug to catch this condition in the future. Looking to take this through the dmaengine tree with a netdev ack. --- Documentation/ABI/removed/net_dma | 8 + Documentation/networking/ip-sysctl.txt | 6 - drivers/dma/Kconfig | 11 - drivers/dma/Makefile | 1 drivers/dma/dmaengine.c | 104 ------------ drivers/dma/ioat/dma.c | 1 drivers/dma/ioat/dma.h | 7 - drivers/dma/ioat/dma_v2.c | 1 drivers/dma/ioat/dma_v3.c | 1 drivers/dma/iovlock.c | 280 -------------------------------- include/linux/dma-debug.h | 6 + include/linux/dmaengine.h | 22 --- include/linux/skbuff.h | 7 - include/linux/tcp.h | 7 - include/net/netdma.h | 32 ---- include/net/sock.h | 18 -- include/net/tcp.h | 7 - kernel/sysctl_binary.c | 1 lib/dma-debug.c | 130 +++++++++++++-- mm/memory.c | 3 net/core/Makefile | 1 net/core/dev.c | 10 - net/core/sock.c | 6 - net/core/user_dma.c | 131 --------------- net/dccp/proto.c | 4 net/ipv4/sysctl_net_ipv4.c | 9 - net/ipv4/tcp.c | 147 ++--------------- net/ipv4/tcp_input.c | 61 ------- net/ipv4/tcp_ipv4.c | 18 -- net/ipv6/tcp_ipv6.c | 13 - net/llc/af_llc.c | 10 + 31 files changed, 161 insertions(+), 902 deletions(-) create mode 100644 Documentation/ABI/removed/net_dma delete mode 100644 drivers/dma/iovlock.c delete mode 100644 include/net/netdma.h delete mode 100644 net/core/user_dma.c -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
