linux/drivers/virtio
Jiang Biao 89da619bc1 virtio_balloon: fix another race between migration and ballooning
Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e22504296d ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: stable@vger.kernel.org
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Huang Chong <huang.chong@zte.com.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-07-30 16:45:33 +03:00
..
Kconfig virtio: make VIRTIO a menuconfig to ease disabling it all 2018-02-01 16:26:43 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
virtio.c virtio: split device_register into device_initialize and device_add 2018-02-01 16:26:45 +02:00
virtio_balloon.c virtio_balloon: fix another race between migration and ballooning 2018-07-30 16:45:33 +03:00
virtio_input.c virtio: wrap find_vqs 2017-05-02 23:41:42 +03:00
virtio_mmio.c virtio: virtio_mmio: make of_device_ids const. 2018-01-31 01:47:35 +02:00
virtio_pci_common.c virtio, vhost: features, fixes 2018-06-16 06:35:02 +09:00
virtio_pci_common.h virtio: add context flag to find vqs 2017-05-02 23:41:43 +03:00
virtio_pci_legacy.c virtio: add context flag to find vqs 2017-05-02 23:41:43 +03:00
virtio_pci_modern.c virtio_pci: support enabling VFs 2018-06-12 04:59:29 +03:00
virtio_ring.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00