kernel/linux.git/drivers/virtio, branch v4.4.171

virtio_balloon: fix another race between migration and ballooning

2018-08-06T14:24:42+00:00

commit 89da619bc18d79bca5304724c11d4ba3b67ce2c6 upstream. 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: e22504296d4f64f ("virtio_balloon: introduce migration primitives to balloon pages") Cc: stable@vger.kernel.org Signed-off-by: Jiang Biao Signed-off-by: Huang Chong Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_balloon: prevent uninitialized variable use

2018-02-25T10:03:42+00:00

commit f0bb2d50dfcc519f06f901aac88502be6ff1df2c upstream. The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized] This seems absolutely right, so we should add an extra check to prevent copying uninitialized stack data into the statistics. >From all I can tell, this has been broken since the statistics code was originally added in 2.6.34. Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)") Signed-off-by: Arnd Bergmann Signed-off-by: Ladi Prosek Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio: release virtio index when fail to device_register

2017-12-16T09:33:48+00:00

commit e60ea67bb60459b95a50a156296041a13e0e380e upstream. index can be reused by other virtio device. Signed-off-by: weiping zhang Reviewed-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_balloon: init 1st buffer in stats vq

2017-03-31T07:49:53+00:00

commit fc8653228c8588a120f6b5dad6983b7b61ff669e upstream. When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch updates the stats before pushing the initial buffer. Alternative fixes: * Push an empty buffer in init_vqs. Not easily done with the current virtio implementation and violates the spec "Driver MUST supply the same subset of statistics in all buffers submitted to the statsq". * Push a buffer with invalid tags in init_vqs. Violates the same spec clause, plus "invalid tag" is not really defined. Note: the spec says: When using the legacy interface, the device SHOULD ignore all values in the first buffer in the statsq supplied by the driver after device initialization. Note: Historically, drivers supplied an uninitialized buffer in the first buffer. Unfortunately QEMU does not seem to implement the recommendation even for the legacy interface. Signed-off-by: Ladi Prosek Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_ring: Make interrupt suppression spec compliant

2016-11-10T15:36:34+00:00

commit 0ea1e4a6d9b62cf29e210d2b4ba9fd43917522e3 upstream. According to the spec, if the VIRTIO_RING_F_EVENT_IDX feature bit is negotiated the driver MUST set flags to 0. Not dirtying the available ring in virtqueue_disable_cb also has a minor positive performance impact, improving L1 dcache load missed by ~0.5% in vring_bench. Writes to the used event field (vring_used_event) are still unconditional. Cc: Michael S. Tsirkin Signed-off-by: Ladi Prosek Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio: fix memory leak in virtqueue_add()

2016-09-07T06:32:36+00:00

commit 58625edf9e2515ed41dac2a24fa8004030a87b87 upstream. When using the indirect buffers feature, 'desc' is allocated in virtqueue_add() but isn't freed before leaving on a ring full error, causing a memory leak. For example, it seems rather clear that this can trigger with virtio net if mergeable buffers are not used. Signed-off-by: Wei Yongjun Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

balloon: check the number of available pages in leak balloon

2016-08-20T16:09:23+00:00

commit 37cf99e08c6fb4dcea0f9ad2b13b6daa8c76a711 upstream. The balloon has a special mechanism that is subscribed to the oom notification which leads to deflation for a fixed number of pages. The number is always fixed even when the balloon is fully deflated. But leak_balloon did not expect that the pages to deflate will be more than taken, and raise a "BUG" in balloon_page_dequeue when page list will be empty. So, the simplest solution would be to check that the number of releases pages is less or equal to the number taken pages. Signed-off-by: Konstantin Neumoin Signed-off-by: Denis V. Lunev CC: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_balloon: fix PFN format for virtio-1

2016-07-27T16:47:34+00:00

commit 87c9403b0d1de4676b0bd273eea68fcf6de68e68 upstream. Everything should be LE when using virtio-1, but the linux balloon driver does not seem to care about that. Reported-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Tested-by: Cornelia Huck Reviewed-by: Cornelia Huck Signed-off-by: Greg Kroah-Hartman

virtio: virtio 1.0 cs04 spec compliance for reset

2016-04-20T06:42:10+00:00

commit 05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c upstream. The spec says: after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Greg Kroah-Hartman

virtio_pci: fix use after free on release

2016-03-03T23:07:18+00:00

commit 2989be09a8a9d62a785137586ad941f916e08f83 upstream. KASan detected a use-after-free error in virtio-pci remove code. In virtio_pci_remove(), vp_dev is still used after being freed in unregister_virtio_device() (in virtio_pci_release_dev() more precisely). To fix, keep a reference until cleanup is done. Fixes: 63bd62a08ca4 ("virtio_pci: defer kfree until release callback") Reported-by: Jerome Marchand Cc: Sasha Levin Signed-off-by: Michael S. Tsirkin Tested-by: Jerome Marchand Signed-off-by: Greg Kroah-Hartman