5c37711d9f
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@linux.alibaba.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.