kernel/linux.git/drivers/virtio, branch v4.19.112

virtio_balloon: prevent pfn array overflow

2020-02-24T07:34:54+00:00

[ Upstream commit 6e9826e77249355c09db6ba41cd3f84e89f4b614 ] Make sure, at build time, that pfn array is big enough to hold a single page. It happens to be true since the PAGE_SHIFT value at the moment is 20, which is 1M - exactly 256 4K balloon pages. Signed-off-by: Michael S. Tsirkin Reviewed-by: David Hildenbrand Signed-off-by: Sasha Levin

virtio-balloon: fix managed page counts when migrating pages between zones

2019-12-17T19:34:43+00:00

commit 63341ab03706e11a31e3dd8ccc0fbc9beaf723f0 upstream. In case we have to migrate a ballon page to a newpage of another zone, the managed page count of both zones is wrong. Paired with memory offlining (which will adjust the managed page count), we can trigger kernel crashes and all kinds of different symptoms. One way to reproduce: 1. Start a QEMU guest with 4GB, no NUMA 2. Hotplug a 1GB DIMM and online the memory to ZONE_NORMAL 3. Inflate the balloon to 1GB 4. Unplug the DIMM (be quick, otherwise unmovable data ends up on it) 5. Observe /proc/zoneinfo Node 0, zone Normal pages free 16810 min 24848885473806 low 18471592959183339 high 36918337032892872 spanned 262144 present 262144 managed 18446744073709533486 6. Do anything that requires some memory (e.g., inflate the balloon some more). The OOM goes crazy and the system crashes [ 238.324946] Out of memory: Killed process 537 (login) total-vm:27584kB, anon-rss:860kB, file-rss:0kB, shmem-rss:00 [ 238.338585] systemd invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0 [ 238.339420] CPU: 0 PID: 1 Comm: systemd Tainted: G D W 5.4.0-next-20191204+ #75 [ 238.340139] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu4 [ 238.341121] Call Trace: [ 238.341337] dump_stack+0x8f/0xd0 [ 238.341630] dump_header+0x61/0x5ea [ 238.341942] oom_kill_process.cold+0xb/0x10 [ 238.342299] out_of_memory+0x24d/0x5a0 [ 238.342625] __alloc_pages_slowpath+0xd12/0x1020 [ 238.343024] __alloc_pages_nodemask+0x391/0x410 [ 238.343407] pagecache_get_page+0xc3/0x3a0 [ 238.343757] filemap_fault+0x804/0xc30 [ 238.344083] ? ext4_filemap_fault+0x28/0x42 [ 238.344444] ext4_filemap_fault+0x30/0x42 [ 238.344789] __do_fault+0x37/0x1a0 [ 238.345087] __handle_mm_fault+0x104d/0x1ab0 [ 238.345450] handle_mm_fault+0x169/0x360 [ 238.345790] do_user_addr_fault+0x20d/0x490 [ 238.346154] do_page_fault+0x31/0x210 [ 238.346468] async_page_fault+0x43/0x50 [ 238.346797] RIP: 0033:0x7f47eba4197e [ 238.347110] Code: Bad RIP value. [ 238.347387] RSP: 002b:00007ffd7c0c1890 EFLAGS: 00010293 [ 238.347834] RAX: 0000000000000002 RBX: 000055d196a20a20 RCX: 00007f47eba4197e [ 238.348437] RDX: 0000000000000033 RSI: 00007ffd7c0c18c0 RDI: 0000000000000004 [ 238.349047] RBP: 00007ffd7c0c1c20 R08: 0000000000000000 R09: 0000000000000033 [ 238.349660] R10: 00000000ffffffff R11: 0000000000000293 R12: 0000000000000001 [ 238.350261] R13: ffffffffffffffff R14: 0000000000000000 R15: 00007ffd7c0c18c0 [ 238.350878] Mem-Info: [ 238.351085] active_anon:3121 inactive_anon:51 isolated_anon:0 [ 238.351085] active_file:12 inactive_file:7 isolated_file:0 [ 238.351085] unevictable:0 dirty:0 writeback:0 unstable:0 [ 238.351085] slab_reclaimable:5565 slab_unreclaimable:10170 [ 238.351085] mapped:3 shmem:111 pagetables:155 bounce:0 [ 238.351085] free:720717 free_pcp:2 free_cma:0 [ 238.353757] Node 0 active_anon:12484kB inactive_anon:204kB active_file:48kB inactive_file:28kB unevictable:0kB iss [ 238.355979] Node 0 DMA free:11556kB min:36kB low:48kB high:60kB reserved_highatomic:0KB active_anon:152kB inactivB [ 238.358345] lowmem_reserve[]: 0 2955 2884 2884 2884 [ 238.358761] Node 0 DMA32 free:2677864kB min:7004kB low:10028kB high:13052kB reserved_highatomic:0KB active_anon:0B [ 238.361202] lowmem_reserve[]: 0 0 72057594037927865 72057594037927865 72057594037927865 [ 238.361888] Node 0 Normal free:193448kB min:99395541895224kB low:73886371836733356kB high:147673348131571488kB reB [ 238.364765] lowmem_reserve[]: 0 0 0 0 0 [ 238.365101] Node 0 DMA: 7*4kB (U) 5*8kB (UE) 6*16kB (UME) 2*32kB (UM) 1*64kB (U) 2*128kB (UE) 3*256kB (UME) 2*512B [ 238.366379] Node 0 DMA32: 0*4kB 1*8kB (U) 2*16kB (UM) 2*32kB (UM) 2*64kB (UM) 1*128kB (U) 1*256kB (U) 1*512kB (U)B [ 238.367654] Node 0 Normal: 1985*4kB (UME) 1321*8kB (UME) 844*16kB (UME) 524*32kB (UME) 300*64kB (UME) 138*128kB (B [ 238.369184] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB [ 238.369915] 130 total pagecache pages [ 238.370241] 0 pages in swap cache [ 238.370533] Swap cache stats: add 0, delete 0, find 0/0 [ 238.370981] Free swap = 0kB [ 238.371239] Total swap = 0kB [ 238.371488] 1048445 pages RAM [ 238.371756] 0 pages HighMem/MovableOnly [ 238.372090] 306992 pages reserved [ 238.372376] 0 pages cma reserved [ 238.372661] 0 pages hwpoisoned In another instance (older kernel), I was able to observe this (negative page count :/): [ 180.896971] Offlined Pages 32768 [ 182.667462] Offlined Pages 32768 [ 184.408117] Offlined Pages 32768 [ 186.026321] Offlined Pages 32768 [ 187.684861] Offlined Pages 32768 [ 189.227013] Offlined Pages 32768 [ 190.830303] Offlined Pages 32768 [ 190.833071] Built 1 zonelists, mobility grouping on. Total pages: -36920272750453009 In another instance (older kernel), I was no longer able to start any process: [root@vm ~]# [ 214.348068] Offlined Pages 32768 [ 215.973009] Offlined Pages 32768 cat /proc/meminfo -bash: fork: Cannot allocate memory [root@vm ~]# cat /proc/meminfo -bash: fork: Cannot allocate memory Fix it by properly adjusting the managed page count when migrating if the zone changed. The managed page count of the zones now looks after unplug of the DIMM (and after deflating the balloon) just like before inflating the balloon (and plugging+onlining the DIMM). We'll temporarily modify the totalram page count. If this ever becomes a problem, we can fine tune by providing helpers that don't touch the totalram pages (e.g., adjust_zone_managed_page_count()). Please note that fixing up the managed page count is only necessary when we adjusted the managed page count when inflating - only if we don't have VIRTIO_BALLOON_F_DEFLATE_ON_OOM. With that feature, the managed page count is not touched when inflating/deflating. Reported-by: Yumei Huang Fixes: 3dcc0571cd64 ("mm: correctly update zone->managed_pages") Cc: # v3.11+ Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Jiang Liu Cc: Andrew Morton Cc: Igor Mammedov Cc: virtualization@lists.linux-foundation.org Signed-off-by: David Hildenbrand Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_ring: fix return code on DMA mapping fails

2019-12-01T08:17:40+00:00

[ Upstream commit f7728002c1c7bfa787b276a31c3ef458739b8e7c ] Commit 780bc7903a32 ("virtio_ring: Support DMA APIs") makes virtqueue_add() return -EIO when we fail to map our I/O buffers. This is a very realistic scenario for guests with encrypted memory, as swiotlb may run out of space, depending on it's size and the I/O load. The virtio-blk driver interprets -EIO form virtqueue_add() as an IO error, despite the fact that swiotlb full is in absence of bugs a recoverable condition. Let us change the return code to -ENOMEM, and make the block layer recover form these failures when virtio-blk encounters the condition described above. Cc: stable@vger.kernel.org Fixes: 780bc7903a32 ("virtio_ring: Support DMA APIs") Signed-off-by: Halil Pasic Tested-by: Michael Mueller Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

virtio_pci: fix a NULL pointer reference in vp_del_vqs

2019-05-10T15:54:08+00:00

[ Upstream commit 6a8aae68c87349dbbcd46eac380bc43cdb98a13b ] If the msix_affinity_masks is alloced failed, then we'll try to free some resources in vp_free_vectors() that may access it directly. We met the following stack in our production: [ 29.296767] BUG: unable to handle kernel NULL pointer dereference at (null) [ 29.311151] IP: [] vp_free_vectors+0x6a/0x150 [virtio_pci] [ 29.324787] PGD 0 [ 29.333224] Oops: 0000 [#1] SMP [...] [ 29.425175] RIP: 0010:[] [] vp_free_vectors+0x6a/0x150 [virtio_pci] [ 29.441405] RSP: 0018:ffff9a55c2dcfa10 EFLAGS: 00010206 [ 29.453491] RAX: 0000000000000000 RBX: ffff9a55c322c400 RCX: 0000000000000000 [ 29.467488] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9a55c322c400 [ 29.481461] RBP: ffff9a55c2dcfa20 R08: 0000000000000000 R09: ffffc1b6806ff020 [ 29.495427] R10: 0000000000000e95 R11: 0000000000aaaaaa R12: 0000000000000000 [ 29.509414] R13: 0000000000010000 R14: ffff9a55bd2d9e98 R15: ffff9a55c322c400 [ 29.523407] FS: 00007fdcba69f8c0(0000) GS:ffff9a55c2840000(0000) knlGS:0000000000000000 [ 29.538472] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.551621] CR2: 0000000000000000 CR3: 000000003ce52000 CR4: 00000000003607a0 [ 29.565886] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.580055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.594122] Call Trace: [ 29.603446] [] vp_request_msix_vectors+0xe2/0x260 [virtio_pci] [ 29.618017] [] vp_try_to_find_vqs+0x95/0x3b0 [virtio_pci] [ 29.632152] [] vp_find_vqs+0x37/0xb0 [virtio_pci] [ 29.645582] [] init_vq+0x153/0x260 [virtio_blk] [ 29.658831] [] virtblk_probe+0xe8/0x87f [virtio_blk] [...] Cc: Gonglei Signed-off-by: Longpeng Signed-off-by: Michael S. Tsirkin Reviewed-by: Gonglei Signed-off-by: Sasha Levin

virtio: Honour 'may_reduce_num' in vring_create_virtqueue

2019-04-17T06:38:52+00:00

commit cf94db21905333e610e479688add629397a4b384 upstream. vring_create_virtqueue() allows the caller to specify via the may_reduce_num parameter whether the vring code is allowed to allocate a smaller ring than specified. However, the split ring allocation code tries to allocate a smaller ring on allocation failure regardless of what the caller specified. This may cause trouble for e.g. virtio-pci in legacy mode, which does not support ring resizing. (The packed ring code does not resize in any case.) Let's fix this by bailing out immediately in the split ring code if the requested size cannot be allocated and may_reduce_num has not been specified. While at it, fix a typo in the usage instructions. Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Reviewed-by: Halil Pasic Reviewed-by: Jens Freimann Signed-off-by: Greg Kroah-Hartman

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2018-08-24T15:45:19+00:00

Pull virtio updates from Michael Tsirkin: "virtio, vhost: fixes, tweaks No new features but a bunch of tweaks such as switching balloon from oom notifier to shrinker" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost/scsi: increase VHOST_SCSI_PREALLOC_PROT_SGLS to 2048 vhost: allow vhost-scsi driver to be built-in virtio: pci-legacy: Validate queue pfn virtio: mmio-v1: Validate queue PFN virtio_balloon: replace oom notifier with shrinker virtio-balloon: kzalloc the vb struct virtio-balloon: remove BUG() in init_vqs

virtio: pci-legacy: Validate queue pfn

2018-08-21T21:56:58+00:00

Legacy PCI over virtio uses a 32bit PFN for the queue. If the queue pfn is too large to fit in 32bits, which we could hit on arm64 systems with 52bit physical addresses (even with 64K page size), we simply miss out a proper link to the other side of the queue. Add a check to validate the PFN, rather than silently breaking the devices. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Marc Zyngier Cc: Christoffer Dall Cc: Peter Maydel Cc: Jean-Philippe Brucker Signed-off-by: Suzuki K Poulose Signed-off-by: Michael S. Tsirkin

virtio: mmio-v1: Validate queue PFN

2018-08-21T21:56:56+00:00

virtio-mmio with virtio-v1 uses a 32bit PFN for the queue. If the queue pfn is too large to fit in 32bits, which we could hit on arm64 systems with 52bit physical addresses (even with 64K page size), we simply miss out a proper link to the other side of the queue. Add a check to validate the PFN, rather than silently breaking the devices. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Marc Zyngier Cc: Christoffer Dall Cc: Peter Maydel Cc: Jean-Philippe Brucker Signed-off-by: Suzuki K Poulose Signed-off-by: Michael S. Tsirkin

virtio_balloon: replace oom notifier with shrinker

2018-08-21T21:56:24+00:00

The OOM notifier is getting deprecated to use for the reasons: - As a callout from the oom context, it is too subtle and easy to generate bugs and corner cases which are hard to track; - It is called too late (after the reclaiming has been performed). Drivers with large amuont of reclaimable memory is expected to release them at an early stage of memory pressure; - The notifier callback isn't aware of oom contrains; Link: https://lkml.org/lkml/2018/7/12/314 This patch replaces the virtio-balloon oom notifier with a shrinker to release balloon pages on memory pressure. The balloon pages are given back to mm adaptively by returning the number of pages that the reclaimer is asking for (i.e. sc->nr_to_scan). Currently the max possible value of sc->nr_to_scan passed to the balloon shrinker is SHRINK_BATCH, which is 128. This is smaller than the limitation that only VIRTIO_BALLOON_ARRAY_PFNS_MAX (256) pages can be returned via one invocation of leak_balloon. But this patch still considers the case that SHRINK_BATCH or shrinker->batch could be changed to a value larger than VIRTIO_BALLOON_ARRAY_PFNS_MAX, which will need to do multiple invocations of leak_balloon. Historically, the feature VIRTIO_BALLOON_F_DEFLATE_ON_OOM has been used to release balloon pages on OOM. We continue to use this feature bit for the shrinker, so the shrinker is only registered when this feature bit has been negotiated with host. Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Cc: Michal Hocko Cc: Andrew Morton Cc: Tetsuo Handa Signed-off-by: Michael S. Tsirkin

virtio-balloon: kzalloc the vb struct

2018-08-21T21:56:24+00:00

Zero all the vb fields at alloaction, so that we don't need to zero-initialize each field one by one later. Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Cc: Tetsuo Handa Signed-off-by: Michael S. Tsirkin