On Wed, Aug 03, 2016 at 11:32:33AM +0200, Vegard Nossum wrote: > On 07/22/2016 01:12 PM, Vegard Nossum wrote: > > The memory allocated by iov_iter_get_pages_alloc() can be allocated with > > vmalloc() if kmalloc() failed -- see get_pages_array(). > > > > In that case we need to free it with vfree(), so let's use kvfree(). > > > > The bug manifests like this: > > > > BUG: unable to handle kernel paging request at ffffeb0400072da0 > > IP: [<ffffffff8139c67b>] kfree+0x4b/0x140 > > PGD 0 > > Oops: 0000 [#1] PREEMPT SMP KASAN > > CPU: 2 PID: 675 Comm: trinity-c2 Not tainted 4.7.0-rc7+ #14 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > > task: ffff8800badef2c0 ti: ffff880069208000 task.ti: ffff880069208000 > > RIP: 0010:[<ffffffff8139c67b>] [<ffffffff8139c67b>] kfree+0x4b/0x140 > > RSP: 0000:ffff88006920f3f0 EFLAGS: 00010282 > > RAX: ffffea0000000000 RBX: ffffc90001cb6000 RCX: 0000000000000000 > > RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffffc90001cb6000 > > RBP: ffff88006920f410 R08: 0000000000000000 R09: dffffc0000000000 > > R10: ffff8800badefa30 R11: 0000056a3d3b0d9f R12: ffff88006920f620 > > R13: ffffeb0400072d80 R14: ffff8800baa94078 R15: 0000000000000000 > > FS: 00007fbd2b437700(0000) GS:ffff88011af00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: ffffeb0400072da0 CR3: 000000006926d000 CR4: 00000000000006e0 > > Stack: > > 0000000000000001 ffff88006920f620 ffffed001755280f ffff8800baa94078 > > ffff88006920f6a8 ffffffff8310442b dffffc0000000000 ffff8800badefa30 > > ffff8800badefa28 ffff88011af1fba0 1ffff1000d241e98 ffff8800ba892150 > > Call Trace: > > [<ffffffff8310442b>] p9_virtio_zc_request+0x72b/0xdb0 > > [<ffffffff830f2116>] p9_client_zc_rpc.constprop.8+0x246/0xb10 > > [<ffffffff830f5d79>] p9_client_read+0x4c9/0x750 > > [<ffffffff8175ceac>] v9fs_fid_readpage+0x14c/0x320 > > [<ffffffff8175d0b6>] v9fs_vfs_readpage+0x36/0x50 > > [<ffffffff812c6f13>] filemap_fault+0x9a3/0xe60 > > [<ffffffff81331878>] __do_fault+0x158/0x300 > > [<ffffffff81339e01>] handle_mm_fault+0x1cf1/0x3c80 > > [<ffffffff810c0aaa>] __do_page_fault+0x30a/0x8e0 > > [<ffffffff810c10df>] do_page_fault+0x2f/0x80 > > [<ffffffff810b5b07>] do_async_page_fault+0x27/0xa0 > > [<ffffffff83296c48>] async_page_fault+0x28/0x30 > > Code: 00 80 41 54 53 49 01 fd 48 0f 42 05 b0 39 67 02 48 89 fb 49 01 c5 48 > > b8 00 00 00 00 00 ea ff ff 49 c1 ed 0c 49 c1 e5 06 49 01 c5 <49> 8b 45 20 > > 48 8d 50 ff a8 01 4c 0f 45 ea 49 8b 55 20 48 8d 42 > > RIP [<ffffffff8139c67b>] kfree+0x4b/0x140 > > RSP <ffff88006920f3f0> > > CR2: ffffeb0400072da0 > > ---[ end trace f3d59a04bafec038 ]--- > > > > Cc: Al Viro <v...@zeniv.linux.org.uk> > > Signed-off-by: Vegard Nossum <vegard.nos...@oracle.com> > > --- > > net/9p/trans_virtio.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > > index 4acb1d5..f24b25c 100644 > > --- a/net/9p/trans_virtio.c > > +++ b/net/9p/trans_virtio.c > > @@ -507,8 +507,8 @@ err_out: > > /* wakeup anybody waiting for slots to pin pages */ > > wake_up(&vp_wq); > > } > > - kfree(in_pages); > > - kfree(out_pages); > > + kvfree(in_pages); > > + kvfree(out_pages); > > return err; > > } > > > > > > Ping? Should this go to somebody else? Added a couple of Ccs. > > > Vegard
I'll pick it up, thanks. Is virtio 9p in odd fixes mode? Anyone interested in maintaining it? I think it's actually kind of broken in virtio 1 mode, and probably in IOMMU_PLATFORM mode as well. The endian-ness also looks questionable - does it actually pass native endian structures guets to host? -- MST
