From fa9fac1725fd38dad414e3729c56c089a7188383 Mon Sep 17 00:00:00 2001 From: Andrey Vagin Date: Thu, 5 Dec 2013 18:36:20 +0400 Subject: [PATCH] virtio-net: determine type of bufs correctly free_unused_bufs must check vi->mergeable_rx_bufs before vi->big_packets, because we use this sequence in other places. Otherwise we allocate buffer of one type, then free it as another type. general protection fault: 0000 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: ip6table_filter ip6_tables iptable_filter ip_tables pcspkr virtio_balloon virtio_net(-) i2c_pii CPU: 0 PID: 400 Comm: rmmod Not tainted 3.13.0-rc2+ #170 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8800b6d2a210 ti: ffff8800aed32000 task.ti: ffff8800aed32000 RIP: 0010:[] [] free_unused_bufs+0xc3/0x190 [virtio_net] RSP: 0018:ffff8800aed33dd8 EFLAGS: 00010202 RAX: ffff8800b1fe2c00 RBX: ffff8800b66a7240 RCX: 6b6b6b6b6b6b6b6b RDX: 6b6b6b6b6b6b6b6b RSI: ffff8800b8419a68 RDI: ffff8800b66a1148 RBP: ffff8800aed33e00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffff8800b66a1148 R14: 0000000000000000 R15: 000077ff80000000 FS: 00007fc4f9c4e740(0000) GS:ffff8800bfa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f63f432f000 CR3: 00000000b6538000 CR4: 00000000000006f0 Stack: ffff8800b66a7240 ffff8800b66a7380 ffff8800377bd3f0 0000000000000000 00000000023302f0 ffff8800aed33e18 ffffffffa00346e2 ffff8800b66a7240 ffff8800aed33e38 ffffffffa003474d ffff8800377bd388 ffff8800377bd390 Call Trace: [] remove_vq_common+0x22/0x40 [virtio_net] [] virtnet_remove+0x4d/0x90 [virtio_net] [] virtio_dev_remove+0x23/0x80 [] __device_release_driver+0x7f/0xf0 [] driver_detach+0xc0/0xd0 [] bus_remove_driver+0x58/0xd0 [] driver_unregister+0x2c/0x50 [] unregister_virtio_driver+0xe/0x10 [] virtio_net_driver_exit+0x10/0x7be [virtio_net] [] SyS_delete_module+0x172/0x220 [] ? trace_hardirqs_on+0xd/0x10 [] ? __audit_syscall_entry+0x9c/0xf0 [] system_call_fastpath+0x16/0x1b Code: c0 74 55 0f 1f 44 00 00 80 7b 30 00 74 7a 48 8b 50 30 4c 89 e6 48 03 73 20 48 85 d2 0f 84 bb 00 00 00 66 0f RIP [] free_unused_bufs+0xc3/0x190 [virtio_net] RSP ---[ end trace edb570ea923cce9c ]--- Fixes: 2613af0ed18a (virtio_net: migrate mergeable rx buffers to page frag allocators) Cc: Michael Dalton Cc: Rusty Russell Cc: "Michael S. Tsirkin" Signed-off-by: Andrey Vagin Acked-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 916241d..930039a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1396,10 +1396,10 @@ static void free_unused_bufs(struct virtnet_info *vi) struct virtqueue *vq = vi->rq[i].vq; while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) { - if (vi->big_packets) - give_pages(&vi->rq[i], buf); - else if (vi->mergeable_rx_bufs) + if (vi->mergeable_rx_bufs) put_page(virt_to_head_page(buf)); + else if (vi->big_packets) + give_pages(&vi->rq[i], buf); else dev_kfree_skb(buf); --vi->rq[i].num; -- 2.7.4