Hello, syzbot found the following issue on: HEAD commit: 0280e3c58f92 Merge tag 'nfs-for-5.17-1' of git://git.linux.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11b3dde4700000 kernel config: https://syzkaller.appspot.com/x/.config?x=916d34c0d501b86 dashboard link: https://syzkaller.appspot.com/bug?extid=476bd1c816c8c9c340d7 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+476bd1c816c8c9c340d7@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in recv_work+0x840/0x8b0 drivers/block/nbd.c:863 Read of size 8 at addr ffff88801886e9b0 by task kworker/u5:5/3653 CPU: 0 PID: 3653 Comm: kworker/u5:5 Not tainted 5.17.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: nbd1-recv recv_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 recv_work+0x840/0x8b0 drivers/block/nbd.c:863 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Allocated by task 7763: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kmalloc_node include/linux/slab.h:604 [inline] __vmalloc_area_node mm/vmalloc.c:2948 [inline] __vmalloc_node_range+0x444/0x1060 mm/vmalloc.c:3107 __vmalloc_node mm/vmalloc.c:3157 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3227 do_ipt_get_ctl+0x60d/0x9d0 net/ipv4/netfilter/ip_tables.c:801 nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116 ip_getsockopt net/ipv4/ip_sockglue.c:1786 [inline] ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1765 tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:4284 __sys_getsockopt+0x21f/0x5f0 net/socket.c:2224 __do_sys_getsockopt net/socket.c:2239 [inline] __se_sys_getsockopt net/socket.c:2236 [inline] __x64_sys_getsockopt+0xba/0x150 net/socket.c:2236 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 29418: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x130/0x160 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kfree+0xcb/0x280 mm/slub.c:4562 krealloc+0x69/0xf0 mm/slab_common.c:1219 nbd_add_socket+0x2cb/0x810 drivers/block/nbd.c:1130 __nbd_ioctl drivers/block/nbd.c:1454 [inline] nbd_ioctl+0x38c/0xb10 drivers/block/nbd.c:1511 blkdev_ioctl+0x37a/0x800 block/ioctl.c:588 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88801886e9b0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff88801886e9b0, ffff88801886e9b8) The buggy address belongs to the page: page:ffffea0000621b80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1886e flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0001d57400 dead000000000002 ffff888010c41280 raw: 0000000000000000 0000000080660066 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 0x12a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY), pid 3634, ts 181715914950, free_ts 181667651758 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab mm/slub.c:1944 [inline] new_slab+0x28a/0x3b0 mm/slub.c:2004 ___slab_alloc+0x87c/0xe90 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] slab_alloc mm/slub.c:3238 [inline] __kmalloc+0x2fb/0x340 mm/slub.c:4420 kmalloc_array include/linux/slab.h:621 [inline] kcalloc include/linux/slab.h:652 [inline] nsim_fib6_event_init drivers/net/netdevsim/fib.c:807 [inline] nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:940 [inline] nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:991 [inline] nsim_fib_event_nb+0x2f1/0xc50 drivers/net/netdevsim/fib.c:1028 call_fib_notifier+0x32/0x70 net/core/fib_notifier.c:24 call_fib6_entry_notifier net/ipv6/ip6_fib.c:373 [inline] fib6_rt_dump net/ipv6/ip6_fib.c:452 [inline] fib6_node_dump+0x1c4/0x2d0 net/ipv6/ip6_fib.c:462 fib6_walk_continue+0x3e9/0x6c0 net/ipv6/ip6_fib.c:2112 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2160 fib6_table_dump net/ipv6/ip6_fib.c:474 [inline] fib6_tables_dump+0x1dc/0x340 net/ipv6/ip6_fib.c:503 fib6_dump+0x47/0x60 net/ipv6/fib6_notifier.c:39 fib_net_dump net/core/fib_notifier.c:71 [inline] register_fib_notifier+0x1fc/0x7b0 net/core/fib_notifier.c:109 nsim_fib_create+0x7a5/0xa60 drivers/net/netdevsim/fib.c:1557 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1352 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3404 qlink_free mm/kasan/quarantine.c:157 [inline] qlist_free_all+0x6d/0x160 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slub.c:3230 [inline] kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3266 __alloc_skb+0x215/0x340 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1158 [inline] nlmsg_new include/net/netlink.h:953 [inline] devlink_param_notify+0xba/0x230 net/core/devlink.c:4729 devlink_notify_register net/core/devlink.c:9112 [inline] devlink_register+0x398/0x4a0 net/core/devlink.c:9164 nsim_drv_probe+0xd81/0x11c0 drivers/net/netdevsim/dev.c:1604 call_driver_probe drivers/base/dd.c:517 [inline] really_probe+0x245/0xcc0 drivers/base/dd.c:596 __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:752 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:782 __device_attach_driver+0x20b/0x2f0 drivers/base/dd.c:899 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427 __device_attach+0x228/0x4a0 drivers/base/dd.c:970 Memory state around the buggy address: ffff88801886e880: fc fc fc fa fc fc fc fc fa fc fc fc fc fb fc fc ffff88801886e900: fc fc fa fc fc fc fc fa fc fc fc fc fa fc fc fc >ffff88801886e980: fc fa fc fc fc fc fa fc fc fc fc fa fc fc fc fc ^ ffff88801886ea00: fa fc fc fc fc fa fc fc fc fc fb fc fc fc fc fa ffff88801886ea80: fc fc fc fc fa fc fc fc fc fb fc fc fc fc fa fc ================================================================== --- This report is generated by a bot. 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