================================================================== BUG: KASAN: slab-use-after-free in qfq_reset_qdisc+0x323/0x420 net/sched/sch_qfq.c:1484 Read of size 8 at addr ffff888024d07850 by task syz.1.5153/25392 CPU: 3 UID: 0 PID: 25392 Comm: syz.1.5153 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 qfq_reset_qdisc+0x323/0x420 net/sched/sch_qfq.c:1484 qdisc_reset+0xe0/0x630 net/sched/sch_generic.c:1034 __qdisc_destroy+0xd3/0x4a0 net/sched/sch_generic.c:1073 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1105 dev_shutdown+0x1d0/0x430 net/sched/sch_generic.c:1493 unregister_netdevice_many_notify+0xb37/0x2590 net/core/dev.c:12369 unregister_netdevice_many net/core/dev.c:12444 [inline] unregister_netdevice_queue net/core/dev.c:12258 [inline] unregister_netdevice_queue+0x305/0x3c0 net/core/dev.c:12248 unregister_netdevice include/linux/netdevice.h:3405 [inline] __tun_detach+0x119c/0x1490 drivers/net/tun.c:621 tun_detach drivers/net/tun.c:637 [inline] tun_chr_close+0xc2/0x230 drivers/net/tun.c:3436 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xfb/0x540 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] __do_fast_syscall_32+0x4a4/0x680 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f76579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000ff91fe9c EFLAGS: 00000202 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 000000000000001e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 25393: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] qfq_change_class+0x2ba/0x1da0 net/sched/sch_qfq.c:479 __tc_ctl_tclass net/sched/sch_api.c:2279 [inline] tc_ctl_tclass+0x59d/0x16c0 net/sched/sch_api.c:2309 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 25393: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6663 [inline] kfree+0x2f8/0x6e0 mm/slub.c:6871 qfq_change_class+0x1576/0x1da0 net/sched/sch_qfq.c:533 __tc_ctl_tclass net/sched/sch_api.c:2279 [inline] tc_ctl_tclass+0x59d/0x16c0 net/sched/sch_api.c:2309 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff888024d07800 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 80 bytes inside of freed 128-byte region [ffff888024d07800, ffff888024d07880) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24d07 anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b442a00 0000000000000000 dead000000000001 raw: 0000000000000000 0000000080100010 00000000f5000000 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 15055, tgid 15054 (syz.3.2328), ts 624568304789, free_ts 624536163301 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_pages_slowpath mm/page_alloc.c:4741 [inline] __alloc_frozen_pages_noprof+0x6d7/0x2430 mm/page_alloc.c:5223 alloc_slab_page mm/slub.c:3077 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0xaf/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5246 [inline] __do_kmalloc_node mm/slub.c:5651 [inline] __kmalloc_node_noprof+0x4d8/0x930 mm/slub.c:5658 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x43/0xf0 mm/slub.c:2123 __memcg_slab_post_alloc_hook+0x24b/0x880 mm/memcontrol.c:3197 memcg_slab_post_alloc_hook mm/slub.c:2338 [inline] slab_post_alloc_hook mm/slub.c:4959 [inline] slab_alloc_node mm/slub.c:5258 [inline] __do_kmalloc_node mm/slub.c:5651 [inline] __kmalloc_node_track_caller_noprof+0x6e3/0x930 mm/slub.c:5759 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608 __alloc_skb+0x186/0x410 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xe0/0x860 net/core/skbuff.c:6712 sock_alloc_send_pskb+0x7f9/0x980 net/core/sock.c:2995 unix_dgram_sendmsg+0x3bc/0x1830 net/unix/af_unix.c:2130 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 page last free pid 7261 tgid 7261 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 vfree+0x1fd/0xb50 mm/vmalloc.c:3466 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3385 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff888024d07700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc ffff888024d07780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888024d07800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888024d07880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888024d07900: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi