Michael S. Tsirkin
2023-Jun-26 07:15 UTC
[syzbot] [net?] [virt?] [kvm?] KASAN: slab-use-after-free Read in __vhost_vq_attach_worker
On Mon, Jun 26, 2023 at 12:06:54AM -0700, syzbot wrote:> Hello, > > syzbot found the following issue on: > > HEAD commit: 8d2be868b42c Add linux-next specific files for 20230623 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12872950a80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d8ac8dd33677e8e0 > dashboard link: https://syzkaller.appspot.com/bug?extid=8540db210d403f1aa214 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c1b70f280000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122ee4cb280000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/2a004483aca3/disk-8d2be868.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/5688cb13b277/vmlinux-8d2be868.xz > kernel image: https://storage.googleapis.com/syzbot-assets/76de0b63bc53/bzImage-8d2be868.xz > > The issue was bisected to: > > commit 21a18f4a51896fde11002165f0e7340f4131d6a0 > Author: Mike Christie <michael.christie at oracle.com> > Date: Tue Jun 13 01:32:46 2023 +0000 > > vhost: allow userspace to create workers > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=130850bf280000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=108850bf280000 > console output: https://syzkaller.appspot.com/x/log.txt?x=170850bf280000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8540db210d403f1aa214 at syzkaller.appspotmail.com > Fixes: 21a18f4a5189 ("vhost: allow userspace to create workers")Mike, would appreciate prompt attention to this as I am preparing a pull request for the merge window and need to make a decision on whether to include your userspace-controlled threading patchset. Thanks!> =================================================================> BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:582 [inline] > BUG: KASAN: slab-use-after-free in __mutex_lock+0x1029/0x1350 kernel/locking/mutex.c:747 > Read of size 8 at addr ffff8880703fff68 by task syz-executor204/5105 > > CPU: 0 PID: 5105 Comm: syz-executor204 Not tainted 6.4.0-rc7-next-20230623-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 > print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:364 > print_report mm/kasan/report.c:475 [inline] > kasan_report+0x11d/0x130 mm/kasan/report.c:588 > __mutex_lock_common kernel/locking/mutex.c:582 [inline] > __mutex_lock+0x1029/0x1350 kernel/locking/mutex.c:747 > __vhost_vq_attach_worker+0xe7/0x390 drivers/vhost/vhost.c:678 > vhost_dev_set_owner+0x670/0xa60 drivers/vhost/vhost.c:892 > vhost_net_set_owner drivers/vhost/net.c:1687 [inline] > vhost_net_ioctl+0x668/0x16a0 drivers/vhost/net.c:1737 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:870 [inline] > __se_sys_ioctl fs/ioctl.c:856 [inline] > __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7fe7a9715629 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fe7a96ba208 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00007fe7a9715629 > RDX: 0000000000000000 RSI: 000000000000af01 RDI: 0000000000000003 > RBP: 00007fe7a979e240 R08: 00007fe7a979e248 R09: 00007fe7a979e248 > R10: 00007fe7a979e248 R11: 0000000000000246 R12: 00007fe7a979e24c > R13: 00007ffcfa04d48f R14: 00007fe7a96ba300 R15: 0000000000022000 > </TASK> > > Allocated by task 5105: > kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 > kasan_set_track+0x25/0x30 mm/kasan/common.c:52 > ____kasan_kmalloc mm/kasan/common.c:374 [inline] > ____kasan_kmalloc mm/kasan/common.c:333 [inline] > __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 > kmalloc include/linux/slab.h:579 [inline] > kzalloc include/linux/slab.h:700 [inline] > vhost_worker_create+0x9c/0x320 drivers/vhost/vhost.c:627 > vhost_dev_set_owner+0x5b9/0xa60 drivers/vhost/vhost.c:885 > vhost_net_set_owner drivers/vhost/net.c:1687 [inline] > vhost_net_ioctl+0x668/0x16a0 drivers/vhost/net.c:1737 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:870 [inline] > __se_sys_ioctl fs/ioctl.c:856 [inline] > __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > Freed by task 5108: > kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 > kasan_set_track+0x25/0x30 mm/kasan/common.c:52 > kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521 > ____kasan_slab_free mm/kasan/common.c:236 [inline] > ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 > kasan_slab_free include/linux/kasan.h:164 [inline] > slab_free_hook mm/slub.c:1792 [inline] > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1818 > slab_free mm/slub.c:3801 [inline] > __kmem_cache_free+0xb8/0x2d0 mm/slub.c:3814 > vhost_worker_destroy drivers/vhost/vhost.c:600 [inline] > vhost_workers_free drivers/vhost/vhost.c:615 [inline] > vhost_dev_cleanup+0x66b/0x850 drivers/vhost/vhost.c:991 > vhost_dev_reset_owner+0x25/0x160 drivers/vhost/vhost.c:923 > vhost_net_reset_owner drivers/vhost/net.c:1621 [inline] > vhost_net_ioctl+0x807/0x16a0 drivers/vhost/net.c:1735 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:870 [inline] > __se_sys_ioctl fs/ioctl.c:856 [inline] > __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The buggy address belongs to the object at ffff8880703fff00 > which belongs to the cache kmalloc-cg-192 of size 192 > The buggy address is located 104 bytes inside of > freed 192-byte region [ffff8880703fff00, ffff8880703fffc0) > > The buggy address belongs to the physical page: > page:ffffea0001c0ffc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x703ff > flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) > page_type: 0xffffffff() > raw: 00fff00000000200 ffff88801284ddc0 dead000000000122 0000000000000000 > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask 0x16cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY), pid 5034, tgid 5034 (syz-executor204), ts 72916757418, free_ts 72797036103 > set_page_owner include/linux/page_owner.h:31 [inline] > post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1570 > prep_new_page mm/page_alloc.c:1577 [inline] > get_page_from_freelist+0xfd9/0x2c40 mm/page_alloc.c:3257 > __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4513 > alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279 > alloc_slab_page mm/slub.c:1862 [inline] > allocate_slab+0x25f/0x390 mm/slub.c:2009 > new_slab mm/slub.c:2062 [inline] > ___slab_alloc+0xbc3/0x15d0 mm/slub.c:3215 > __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3314 > __slab_alloc_node mm/slub.c:3367 [inline] > slab_alloc_node mm/slub.c:3460 [inline] > __kmem_cache_alloc_node+0x143/0x350 mm/slub.c:3509 > __do_kmalloc_node mm/slab_common.c:984 [inline] > __kmalloc_node+0x51/0x1a0 mm/slab_common.c:992 > kmalloc_node include/linux/slab.h:599 [inline] > kvmalloc_node+0xa2/0x1a0 mm/util.c:604 > kvmalloc include/linux/slab.h:717 [inline] > kvzalloc include/linux/slab.h:725 [inline] > netif_alloc_rx_queues net/core/dev.c:9847 [inline] > alloc_netdev_mqs+0xbde/0x1270 net/core/dev.c:10660 > ieee80211_if_add+0x1b7/0x19d0 net/mac80211/iface.c:2099 > ieee80211_register_hw+0x37e5/0x40e0 net/mac80211/main.c:1407 > mac80211_hwsim_new_radio+0x26e6/0x4c70 drivers/net/wireless/virtual/mac80211_hwsim.c:5303 > hwsim_new_radio_nl+0xacf/0x1210 drivers/net/wireless/virtual/mac80211_hwsim.c:5983 > genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:970 > page last free stack trace: > reset_page_owner include/linux/page_owner.h:24 [inline] > free_pages_prepare mm/page_alloc.c:1161 [inline] > free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2384 > free_unref_page+0x33/0x370 mm/page_alloc.c:2479 > __unfreeze_partials+0x1fe/0x220 mm/slub.c:2647 > qlink_free mm/kasan/quarantine.c:166 [inline] > qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185 > kasan_quarantine_reduce+0x195/0x220 mm/kasan/quarantine.c:292 > __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:305 > kasan_slab_alloc include/linux/kasan.h:188 [inline] > slab_post_alloc_hook mm/slab.h:750 [inline] > slab_alloc_node mm/slub.c:3470 [inline] > __kmem_cache_alloc_node+0x1ce/0x350 mm/slub.c:3509 > __do_kmalloc_node mm/slab_common.c:984 [inline] > __kmalloc_node+0x51/0x1a0 mm/slab_common.c:992 > kmalloc_node include/linux/slab.h:599 [inline] > kvmalloc_node+0xa2/0x1a0 mm/util.c:604 > kvmalloc include/linux/slab.h:717 [inline] > seq_buf_alloc fs/seq_file.c:38 [inline] > seq_read_iter+0x7fb/0x12d0 fs/seq_file.c:210 > kernfs_fop_read_iter+0x4ce/0x690 fs/kernfs/file.c:279 > call_read_iter include/linux/fs.h:1865 [inline] > new_sync_read fs/read_write.c:389 [inline] > vfs_read+0x4a8/0x8d0 fs/read_write.c:470 > ksys_read+0x122/0x250 fs/read_write.c:613 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > Memory state around the buggy address: > ffff8880703ffe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8880703ffe80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc > >ffff8880703fff00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8880703fff80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff888070400000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > =================================================================> > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller at googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > If the bug is already fixed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > If you want to change bug's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the bug is a duplicate of another bug, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
Mike Christie
2023-Jun-26 15:03 UTC
[syzbot] [net?] [virt?] [kvm?] KASAN: slab-use-after-free Read in __vhost_vq_attach_worker
On 6/26/23 2:15 AM, Michael S. Tsirkin wrote:> On Mon, Jun 26, 2023 at 12:06:54AM -0700, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 8d2be868b42c Add linux-next specific files for 20230623 >> git tree: linux-next >> console+strace: https://syzkaller.appspot.com/x/log.txt?x=12872950a80000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=d8ac8dd33677e8e0 >> dashboard link: https://syzkaller.appspot.com/bug?extid=8540db210d403f1aa214 >> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c1b70f280000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122ee4cb280000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/2a004483aca3/disk-8d2be868.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/5688cb13b277/vmlinux-8d2be868.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/76de0b63bc53/bzImage-8d2be868.xz >> >> The issue was bisected to: >> >> commit 21a18f4a51896fde11002165f0e7340f4131d6a0 >> Author: Mike Christie <michael.christie at oracle.com> >> Date: Tue Jun 13 01:32:46 2023 +0000 >> >> vhost: allow userspace to create workers >> >> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=130850bf280000 >> final oops: https://syzkaller.appspot.com/x/report.txt?x=108850bf280000 >> console output: https://syzkaller.appspot.com/x/log.txt?x=170850bf280000 >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+8540db210d403f1aa214 at syzkaller.appspotmail.com >> Fixes: 21a18f4a5189 ("vhost: allow userspace to create workers") > > Mike, would appreciate prompt attention to this as I am preparing > a pull request for the merge window and need to make a > decision on whether to include your userspace-controlled > threading patchset. >Do you want me to resubmit the patchset or submit a patch against your vhost branch? The bug is that vhost-net can call vhost_dev_reset_owner and that will free the workers. However, I leave the virtqueue->worker pointer set so we end up referencing the freed workers later on. When I handled a review comment between v5 and v6, I deleted that code thinking it was also not needed. So the fix is: diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ab79b064aade..5a07e220e46d 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -607,6 +607,10 @@ static void vhost_workers_free(struct vhost_dev *dev) if (!dev->use_worker) return; + + for (i = 0; i < dev->nvqs; i++) + rcu_assign_pointer(dev->vqs[i]->worker, NULL); + /* * Free the default worker we created and cleanup workers userspace * created but couldn't clean up (it forgot or crashed).