Jason Wang
2021-May-31 03:50 UTC
[PATCH net 1/2] virtio-net: fix for unable to handle page fault for address
? 2021/5/14 ??11:16, Xuan Zhuo ??:> In merge mode, when xdp is enabled, if the headroom of buf is smaller > than virtnet_get_headroom(), xdp_linearize_page() will be called but the > variable of "headroom" is still 0, which leads to wrong logic after > entering page_to_skb(). > > [ 16.600944] BUG: unable to handle page fault for address: ffffecbfff7b43c8[ 16.602175] #PF: supervisor read access in kernel mode > [ 16.603350] #PF: error_code(0x0000) - not-present page > [ 16.604200] PGD 0 P4D 0 > [ 16.604686] Oops: 0000 [#1] SMP PTI > [ 16.605306] CPU: 4 PID: 715 Comm: sh Tainted: G B 5.12.0+ #312 > [ 16.606429] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/04 > [ 16.608217] RIP: 0010:unmap_page_range+0x947/0xde0 > [ 16.609014] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065 > [ 16.611863] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286 > [ 16.612720] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359 > [ 16.613853] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005 > [ 16.614976] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030 > [ 16.616124] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f > [ 16.617276] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000 > [ 16.618423] FS: 0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000 > [ 16.619738] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 16.620670] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0 > [ 16.621792] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 16.622920] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 16.624047] Call Trace: > [ 16.624525] ? release_pages+0x24d/0x730 > [ 16.625209] unmap_single_vma+0xa9/0x130 > [ 16.625885] unmap_vmas+0x76/0xf0 > [ 16.626480] exit_mmap+0xa0/0x210 > [ 16.627129] mmput+0x67/0x180 > [ 16.627673] do_exit+0x3d1/0xf10 > [ 16.628259] ? do_user_addr_fault+0x231/0x840 > [ 16.629000] do_group_exit+0x53/0xd0 > [ 16.629631] __x64_sys_exit_group+0x1d/0x20 > [ 16.630354] do_syscall_64+0x3c/0x80 > [ 16.630988] entry_SYSCALL_64_after_hwframe+0x44/0xae > [ 16.631828] RIP: 0033:0x7f1a043d0191 > [ 16.632464] Code: Unable to access opcode bytes at RIP 0x7f1a043d0167. > [ 16.633502] RSP: 002b:00007ffe3d993308 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > [ 16.634737] RAX: ffffffffffffffda RBX: 00007f1a044c9490 RCX: 00007f1a043d0191 > [ 16.635857] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 > [ 16.636986] RBP: 0000000000000000 R08: ffffffffffffff88 R09: 0000000000000001 > [ 16.638120] R10: 0000000000000008 R11: 0000000000000246 R12: 00007f1a044c9490 > [ 16.639245] R13: 0000000000000001 R14: 00007f1a044c9968 R15: 0000000000000000 > [ 16.640408] Modules linked in: > [ 16.640958] CR2: ffffecbfff7b43c8 > [ 16.641557] ---[ end trace bc4891c6ce46354c ]--- > [ 16.642335] RIP: 0010:unmap_page_range+0x947/0xde0 > [ 16.643135] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065 > [ 16.645983] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286 > [ 16.646845] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359 > [ 16.647970] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005 > [ 16.649091] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030 > [ 16.650250] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f > [ 16.651394] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000 > [ 16.652529] FS: 0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000 > [ 16.653887] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 16.654841] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0 > [ 16.655992] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 16.657150] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 16.658290] Kernel panic - not syncing: Fatal exception > [ 16.659613] Kernel Offset: disabled > [ 16.660234] ---[ end Kernel panic - not syncing: Fatal exception ]--- > > Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom") > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > Acked-by: Michael S. Tsirkin <mst at redhat.com> > --- > drivers/net/virtio_net.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 9b6a4a875c55..3e46c12dde08 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > struct page *page, unsigned int offset, > unsigned int len, unsigned int truesize, > bool hdr_valid, unsigned int metasize, > - unsigned int headroom) > + bool whole_page) > { > struct sk_buff *skb; > struct virtio_net_hdr_mrg_rxbuf *hdr; > @@ -398,12 +398,12 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > else > hdr_padded_len = sizeof(struct padded_vnet_hdr); > > - /* If headroom is not 0, there is an offset between the beginning of the > + /* If whole_page, there is an offset between the beginning of the > * data and the allocated space, otherwise the data and the allocated > * space are aligned. > */ > - if (headroom) { > - /* Buffers with headroom use PAGE_SIZE as alloc size, > + if (whole_page) { > + /* Buffers with whole_page use PAGE_SIZE as alloc size, > * see add_recvbuf_mergeable() + get_mergeable_buf_len() > */ > truesize = PAGE_SIZE; > @@ -958,7 +958,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > put_page(page); > head_skb = page_to_skb(vi, rq, xdp_page, offset, > len, PAGE_SIZE, false, > - metasize, headroom); > + metasize, true); > return head_skb;Patch looks correct but I'd rather go with a much simple one: How about just use VIRTNET_XDP_HEADROOM instead of headroom here? Thanks> } > break; > @@ -1016,7 +1016,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > } > > head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog, > - metasize, headroom); > + metasize, !!headroom); > curr_skb = head_skb; > > if (unlikely(!curr_skb))
Xuan Zhuo
2021-May-31 10:56 UTC
[PATCH net 1/2] virtio-net: fix for unable to handle page fault for address
On Mon, 31 May 2021 11:50:00 +0800, Jason Wang <jasowang at redhat.com> wrote:> > ? 2021/5/14 ??11:16, Xuan Zhuo ??: > > In merge mode, when xdp is enabled, if the headroom of buf is smaller > > than virtnet_get_headroom(), xdp_linearize_page() will be called but the > > variable of "headroom" is still 0, which leads to wrong logic after > > entering page_to_skb(). > > > > [ 16.600944] BUG: unable to handle page fault for address: ffffecbfff7b43c8[ 16.602175] #PF: supervisor read access in kernel mode > > [ 16.603350] #PF: error_code(0x0000) - not-present page > > [ 16.604200] PGD 0 P4D 0 > > [ 16.604686] Oops: 0000 [#1] SMP PTI > > [ 16.605306] CPU: 4 PID: 715 Comm: sh Tainted: G B 5.12.0+ #312 > > [ 16.606429] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/04 > > [ 16.608217] RIP: 0010:unmap_page_range+0x947/0xde0 > > [ 16.609014] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065 > > [ 16.611863] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286 > > [ 16.612720] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359 > > [ 16.613853] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005 > > [ 16.614976] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030 > > [ 16.616124] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f > > [ 16.617276] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000 > > [ 16.618423] FS: 0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000 > > [ 16.619738] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 16.620670] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0 > > [ 16.621792] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > [ 16.622920] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > [ 16.624047] Call Trace: > > [ 16.624525] ? release_pages+0x24d/0x730 > > [ 16.625209] unmap_single_vma+0xa9/0x130 > > [ 16.625885] unmap_vmas+0x76/0xf0 > > [ 16.626480] exit_mmap+0xa0/0x210 > > [ 16.627129] mmput+0x67/0x180 > > [ 16.627673] do_exit+0x3d1/0xf10 > > [ 16.628259] ? do_user_addr_fault+0x231/0x840 > > [ 16.629000] do_group_exit+0x53/0xd0 > > [ 16.629631] __x64_sys_exit_group+0x1d/0x20 > > [ 16.630354] do_syscall_64+0x3c/0x80 > > [ 16.630988] entry_SYSCALL_64_after_hwframe+0x44/0xae > > [ 16.631828] RIP: 0033:0x7f1a043d0191 > > [ 16.632464] Code: Unable to access opcode bytes at RIP 0x7f1a043d0167. > > [ 16.633502] RSP: 002b:00007ffe3d993308 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 > > [ 16.634737] RAX: ffffffffffffffda RBX: 00007f1a044c9490 RCX: 00007f1a043d0191 > > [ 16.635857] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 > > [ 16.636986] RBP: 0000000000000000 R08: ffffffffffffff88 R09: 0000000000000001 > > [ 16.638120] R10: 0000000000000008 R11: 0000000000000246 R12: 00007f1a044c9490 > > [ 16.639245] R13: 0000000000000001 R14: 00007f1a044c9968 R15: 0000000000000000 > > [ 16.640408] Modules linked in: > > [ 16.640958] CR2: ffffecbfff7b43c8 > > [ 16.641557] ---[ end trace bc4891c6ce46354c ]--- > > [ 16.642335] RIP: 0010:unmap_page_range+0x947/0xde0 > > [ 16.643135] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065 > > [ 16.645983] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286 > > [ 16.646845] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359 > > [ 16.647970] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005 > > [ 16.649091] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030 > > [ 16.650250] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f > > [ 16.651394] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000 > > [ 16.652529] FS: 0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000 > > [ 16.653887] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 16.654841] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0 > > [ 16.655992] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > [ 16.657150] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > [ 16.658290] Kernel panic - not syncing: Fatal exception > > [ 16.659613] Kernel Offset: disabled > > [ 16.660234] ---[ end Kernel panic - not syncing: Fatal exception ]--- > > > > Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom") > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > > Acked-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > drivers/net/virtio_net.c | 12 ++++++------ > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 9b6a4a875c55..3e46c12dde08 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > > struct page *page, unsigned int offset, > > unsigned int len, unsigned int truesize, > > bool hdr_valid, unsigned int metasize, > > - unsigned int headroom) > > + bool whole_page) > > { > > struct sk_buff *skb; > > struct virtio_net_hdr_mrg_rxbuf *hdr; > > @@ -398,12 +398,12 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > > else > > hdr_padded_len = sizeof(struct padded_vnet_hdr); > > > > - /* If headroom is not 0, there is an offset between the beginning of the > > + /* If whole_page, there is an offset between the beginning of the > > * data and the allocated space, otherwise the data and the allocated > > * space are aligned. > > */ > > - if (headroom) { > > - /* Buffers with headroom use PAGE_SIZE as alloc size, > > + if (whole_page) { > > + /* Buffers with whole_page use PAGE_SIZE as alloc size, > > * see add_recvbuf_mergeable() + get_mergeable_buf_len() > > */ > > truesize = PAGE_SIZE; > > @@ -958,7 +958,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > > put_page(page); > > head_skb = page_to_skb(vi, rq, xdp_page, offset, > > len, PAGE_SIZE, false, > > - metasize, headroom); > > + metasize, true); > > return head_skb; > > > Patch looks correct but I'd rather go with a much simple one: > > How about just use VIRTNET_XDP_HEADROOM instead of headroom here? > > ThanksOK. Thanks.> > > > } > > break; > > @@ -1016,7 +1016,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > > } > > > > head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog, > > - metasize, headroom); > > + metasize, !!headroom); > > curr_skb = head_skb; > > > > if (unlikely(!curr_skb)) >