{"action":"created","issue":{"url":"https://api.github.com/repos/raspberrypi/linux/issues/837","labels_url":"https://api.github.com/repos/raspberrypi/linux/issues/837/labels{/name}","comments_url":"https://api.github.com/repos/raspberrypi/linux/issues/837/comments","events_url":"https://api.github.com/repos/raspberrypi/linux/issues/837/events","html_url":"https://github.com/raspberrypi/linux/issues/837","id":57948727,"number":837,"title":"WARNING: CPU: 0 PID: 0 at net/core/skbuff.c:3995","user":{"login":"simonhiggs","id":11042589,"avatar_url":"https://avatars.githubusercontent.com/u/11042589?v=3","gravatar_id":"","url":"https://api.github.com/users/simonhiggs","html_url":"https://github.com/simonhiggs","followers_url":"https://api.github.com/users/simonhiggs/followers","following_url":"https://api.github.com/users/simonhiggs/following{/other_user}","gists_url":"https://api.github.com/users/simonhiggs/gists{/gist_id}","starred_url":"https://api.github.com/users/simonhiggs/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/simonhiggs/subscriptions","organizations_url":"https://api.github.com/users/simonhiggs/orgs","repos_url":"https://api.github.com/users/simonhiggs/repos","events_url":"https://api.github.com/users/simonhiggs/events{/privacy}","received_events_url":"https://api.github.com/users/simonhiggs/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":12,"created_at":"2015-02-17T16:47:00Z","updated_at":"2015-04-17T13:19:14Z","closed_at":null,"body":"Hello. It's been suggested on the Arch Linux ARM forums that I post here.\r\nI'm using a Pi 2 with a HiFiBerry Digi+ SPDIF interface. Occasionally I have a loud stuttering whilst streaming from a NAS, and have the following in the logs\r\n```\r\n[  298.902324] ------------[ cut here ]------------\r\n[  298.907282] WARNING: CPU: 0 PID: 0 at net/core/skbuff.c:3995 skb_try_coalesce+0x320/0x378()\r\n[  298.915988] Modules linked in: snd_soc_bcm2708_i2s snd_soc_hifiberry_digi snd_soc_wm8804 regmap_mmio snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm regmap_spi snd_timer regmap_i2c snd i2c_bcm2708 leds_gpio led_class uio_pdrv_genirq uio sch_fq_codel bcm2708_rng rng_core ipv6\r\n[  298.942115] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.7-4-ARCH #1\r\n[  298.948937] [<c0015630>] (unwind_backtrace) from [<c0011f2c>] (show_stack+0x10/0x14)\r\n[  298.957014] [<c0011f2c>] (show_stack) from [<c0734b44>] (dump_stack+0x84/0xc4)\r\n[  298.964421] [<c0734b44>] (dump_stack) from [<c002ca84>] (warn_slowpath_common+0x74/0x90)\r\n[  298.972751] [<c002ca84>] (warn_slowpath_common) from [<c002cb3c>] (warn_slowpath_null+0x1c/0x24)\r\n[  298.981794] [<c002cb3c>] (warn_slowpath_null) from [<c065db4c>] (skb_try_coalesce+0x320/0x378)\r\n[  298.990631] [<c065db4c>] (skb_try_coalesce) from [<c06b2108>] (tcp_try_coalesce.part.38+0x28/0xbc)\r\n[  298.999841] [<c06b2108>] (tcp_try_coalesce.part.38) from [<c06b38dc>] (tcp_data_queue+0x7a8/0xca8)\r\n[  299.009019] [<c06b38dc>] (tcp_data_queue) from [<c06b55d0>] (tcp_rcv_established+0x150/0x63c)\r\n[  299.034790] [<c06b55d0>] (tcp_rcv_established) from [<c06bd998>] (tcp_v4_do_rcv+0x180/0x394)\r\n[  299.078781] [<c06bd998>] (tcp_v4_do_rcv) from [<c06c01a4>] (tcp_v4_rcv+0x8c4/0x8cc)\r\n[  299.121648] [<c06c01a4>] (tcp_v4_rcv) from [<c069c830>] (ip_local_deliver_finish+0xe0/0x2c8)\r\n[  299.161879] [<c069c830>] (ip_local_deliver_finish) from [<c0667f9c>] (__netif_receive_skb_core+0x664/0x85c)\r\n[  299.203365] [<c0667f9c>] (__netif_receive_skb_core) from [<c066b8d8>] (process_backlog+0x8c/0x138)\r\n[  299.244130] [<c066b8d8>] (process_backlog) from [<c066b71c>] (net_rx_action+0x13c/0x26c)\r\n[  299.284239] [<c066b71c>] (net_rx_action) from [<c00303f4>] (__do_softirq+0x128/0x320)\r\n[  299.324355] [<c00303f4>] (__do_softirq) from [<c0030880>] (irq_exit+0xb8/0xf4)\r\n[  299.347914] [<c0030880>] (irq_exit) from [<c0073508>] (__handle_domain_irq+0xa8/0x104)\r\n[  299.388094] [<c0073508>] (__handle_domain_irq) from [<c073a830>] (__irq_svc+0x30/0x144)\r\n[  299.428484] [<c073a830>] (__irq_svc) from [<c000f13c>] (arch_cpu_idle+0x38/0x3c)\r\n[  299.468195] [<c000f13c>] (arch_cpu_idle) from [<c0064528>] (cpu_startup_entry+0x358/0x3e4)\r\n[  299.508846] [<c0064528>] (cpu_startup_entry) from [<c09f7c64>] (start_kernel+0x3a0/0x3ac)\r\n[  299.549293] ---[ end trace 90c67f02a1d32a34 ]---\r\n```\r\nI've no idea about what this means, let alone how to fix. Any help most welcome.\r\n\r\nSimon.\r\n\r\n```Linux raspi 3.18.7-4-ARCH #1 SMP PREEMPT Mon Feb 16 11:39:41 MST 2015 armv7l GNU/Linux```"},"comment":{"url":"https://api.github.com/repos/raspberrypi/linux/issues/comments/93984313","html_url":"https://github.com/raspberrypi/linux/issues/837#issuecomment-93984313","issue_url":"https://api.github.com/repos/raspberrypi/linux/issues/837","id":93984313,"user":{"login":"lucazen","id":10073681,"avatar_url":"https://avatars.githubusercontent.com/u/10073681?v=3","gravatar_id":"","url":"https://api.github.com/users/lucazen","html_url":"https://github.com/lucazen","followers_url":"https://api.github.com/users/lucazen/followers","following_url":"https://api.github.com/users/lucazen/following{/other_user}","gists_url":"https://api.github.com/users/lucazen/gists{/gist_id}","starred_url":"https://api.github.com/users/lucazen/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/lucazen/subscriptions","organizations_url":"https://api.github.com/users/lucazen/orgs","repos_url":"https://api.github.com/users/lucazen/repos","events_url":"https://api.github.com/users/lucazen/events{/privacy}","received_events_url":"https://api.github.com/users/lucazen/received_events","type":"User","site_admin":false},"created_at":"2015-04-17T13:19:14Z","updated_at":"2015-04-17T13:19:14Z","body":"Hi,\r\nafter a week of test in which i streamed once a day, i haven't had evidence of new errors.\r\n\r\nThis is my settings:\r\n\r\n```\r\npi@raspzen ~ $ cat /boot/cmdline.txt \r\ndwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait smsc95xx.turbo_mode=N\r\n```\r\n and /etc/samba/smb.conf\r\n```\r\n socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65535 SO_SNDBUF=65535 SO_KEEPALIVE\r\n        write cache size = 2097152 # 2MB - you should test some values it's pretty memory intesive\r\n        use sendfile = yes\r\n```\r\nThanks,\r\nLuca"}}