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BUG: KASAN: use-after-free in tcf_block_put+0xf6/0x100 net/sched/cls_api.c:797
Read of size 8 at addr ffff8880b4e50260 by task syz-executor.0/26401

CPU: 0 PID: 26401 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 tcf_block_put+0xf6/0x100 net/sched/cls_api.c:797
 cake_destroy+0x3f/0x80 net/sched/sch_cake.c:2634
 qdisc_create+0xb70/0x1130 net/sched/sch_api.c:1204
 tc_modify_qdisc+0x50d/0x1a80 net/sched/sch_api.c:1572
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f15b8444ae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f15b7399188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f15b8558028 RCX: 00007f15b8444ae9
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000005
RBP: 00007f15b73991d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007ffc6445cc3f R14: 00007f15b7399300 R15: 0000000000022000

Allocated by task 26401:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 tcf_block_create net/sched/cls_api.c:505 [inline]
 tcf_block_get_ext+0x26a/0x13b0 net/sched/cls_api.c:680
 tcf_block_get+0xa9/0xf0 net/sched/cls_api.c:742
 cake_init+0x2c9/0xb50 net/sched/sch_cake.c:2667
 qdisc_create+0x579/0x1130 net/sched/sch_api.c:1156
 tc_modify_qdisc+0x50d/0x1a80 net/sched/sch_api.c:1572
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 26401:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 tcf_block_put_ext.part.0+0x5a1/0x6e0 net/sched/cls_api.c:784
 tcf_block_put_ext net/sched/cls_api.c:754 [inline]
 tcf_block_put+0xad/0x100 net/sched/cls_api.c:797
 cake_destroy net/sched/sch_cake.c:2634 [inline]
 cake_init+0xa9a/0xb50 net/sched/sch_cake.c:2710
 qdisc_create+0x579/0x1130 net/sched/sch_api.c:1156
 tc_modify_qdisc+0x50d/0x1a80 net/sched/sch_api.c:1572
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880b4e50240
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 32 bytes inside of
 128-byte region [ffff8880b4e50240, ffff8880b4e502c0)
The buggy address belongs to the page:
page:ffffea0002d39400 count:1 mapcount:0 mapping:ffff88813bff0640 index:0x0
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea000294fa48 ffffea00024ff188 ffff88813bff0640
raw: 0000000000000000 ffff8880b4e50000 0000000100000015 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b4e50100: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880b4e50180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880b4e50200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                       ^
 ffff8880b4e50280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880b4e50300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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