381ebff258
[ Upstream commit 3f01ddb962dc506916c243f9524e8bef97119b77 ] On receiving a packet the state index points to the rstate which must be used to fill up IP and TCP headers. But if the state index points to a rstate which is unitialized, i.e. filled with zeros, it gets stuck in an infinite loop inside ip_fast_csum trying to compute the ip checsum of a header with zero length. 89.666953: <2> [<ffffff9dd3e94d38>] slhc_uncompress+0x464/0x468 89.666965: <2> [<ffffff9dd3e87d88>] ppp_receive_nonmp_frame+0x3b4/0x65c 89.666978: <2> [<ffffff9dd3e89dd4>] ppp_receive_frame+0x64/0x7e0 89.666991: <2> [<ffffff9dd3e8a708>] ppp_input+0x104/0x198 89.667005: <2> [<ffffff9dd3e93868>] pppopns_recv_core+0x238/0x370 89.667027: <2> [<ffffff9dd4428fc8>] __sk_receive_skb+0xdc/0x250 89.667040: <2> [<ffffff9dd3e939e4>] pppopns_recv+0x44/0x60 89.667053: <2> [<ffffff9dd4426848>] __sock_queue_rcv_skb+0x16c/0x24c 89.667065: <2> [<ffffff9dd4426954>] sock_queue_rcv_skb+0x2c/0x38 89.667085: <2> [<ffffff9dd44f7358>] raw_rcv+0x124/0x154 89.667098: <2> [<ffffff9dd44f7568>] raw_local_deliver+0x1e0/0x22c 89.667117: <2> [<ffffff9dd44c8ba0>] ip_local_deliver_finish+0x70/0x24c 89.667131: <2> [<ffffff9dd44c92f4>] ip_local_deliver+0x100/0x10c ./scripts/faddr2line vmlinux slhc_uncompress+0x464/0x468 output: ip_fast_csum at arch/arm64/include/asm/checksum.h:40 (inlined by) slhc_uncompress at drivers/net/slip/slhc.c:615 Adding a variable to indicate if the current rstate is initialized. If such a packet arrives, move to toss state. Signed-off-by: Tejaswi Tanikella <tejaswit@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.