From: Cornelia H. <cor...@de...> - 2016-08-02 11:39:57
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On Sat, 30 Jul 2016 23:42:18 +0200 Vegard Nossum <veg...@or...> wrote: > Hi, > > With fault injection triggering an allocation failure for the > alloc_indirect() call in virtqueue_add() I'm seeing a hang in > p9_virtio_zc_request() -- it seems to be waiting here indefinitely > (i.e. at least 120 seconds): > > err = wait_event_interruptible(*req->wq, > req->status >= REQ_STATUS_RCVD); > > Maybe somebody who is already familiar with the could would have a look? > > Stack trace for the memory allocation failure: > > CPU: 2 PID: 3877 Comm: trinity-c2 Not tainted 4.7.0+ #70 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > ffffffff84354a78 ffff88010594f2e8 ffffffff81d72f91 ffffffff84354a60 > 1ffff10020b29e62 ffff88010594f398 ffffffff81e07df7 00007faad2003fff > 0000000000000064 ffffffffffffffff 0000000041b58ab3 ffffffff840a481c > Call Trace: > [...] > [<ffffffff81473886>] __kmalloc+0x66/0x2e0 > [<ffffffff81f7c6b4>] alloc_indirect.isra.8+0x24/0xa0 > [<ffffffff81f7d37f>] virtqueue_add_sgs+0x41f/0xc90 > [<ffffffff836eb281>] p9_virtio_zc_request+0x531/0xdb0 > [<ffffffff836d6ecf>] p9_client_zc_rpc.constprop.14+0x23f/0xe80 > [<ffffffff836db77c>] p9_client_read+0x4bc/0x8d0 > [<ffffffff8193f0a3>] v9fs_file_read_iter+0xd3/0x190 > [<ffffffff814b4b62>] do_iter_readv_writev+0x212/0x490 > [<ffffffff814b6be9>] do_readv_writev+0x359/0x660 > [<ffffffff814babc7>] vfs_readv+0x67/0xa0 > [<ffffffff814bacd8>] do_readv+0xd8/0x270 > > Stack trace for the stuck call: > > NMI backtrace for cpu 2 > CPU: 2 PID: 3877 Comm: trinity-c2 Not tainted 4.7.0+ #70 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > task: ffff8801174f5b00 task.stack: ffff880105948000 > RIP: 0010:[<ffffffff810b02a0>] [<ffffffff810b02a0>] > __default_send_IPI_dest_field+0xe0/0x130 > Call Trace: > [...] > [<ffffffff811d584e>] prepare_to_wait_event+0x19e/0x410 > [<ffffffff836eb790>] p9_virtio_zc_request+0xa40/0xdb0 > [<ffffffff836d6ecf>] p9_client_zc_rpc.constprop.14+0x23f/0xe80 > [<ffffffff836db77c>] p9_client_read+0x4bc/0x8d0 > [<ffffffff8193f0a3>] v9fs_file_read_iter+0xd3/0x190 > [<ffffffff814b4b62>] do_iter_readv_writev+0x212/0x490 > [<ffffffff814b6be9>] do_readv_writev+0x359/0x660 > [<ffffffff814babc7>] vfs_readv+0x67/0xa0 > [<ffffffff814bacd8>] do_readv+0xd8/0x270 What happens is that the code falls back to direct virtio addressing (after indirect addressing failed) - and this should work. I'm more inclined to suspect a qemu instead of a kernel bug, as your qemu version is quite old and there have been fixes in the virtio buffer handling and virtio-9p in the meantime. (I'm suspecting "virtio-9p: fix any_layout".) Could you retry with a more recent qemu (at least version 2.4)? |