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BUG: KASAN: use-after-free in tcindex_set_parms+0x17fd/0x1a00 net/sched/cls_tcindex.c:455
Write of size 16 at addr ffff8880a1cfe630 by task syz-executor556/9549

CPU: 1 PID: 9549 Comm: syz-executor556 Not tainted 5.6.0-rc3-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x32 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 tcindex_set_parms+0x17fd/0x1a00 net/sched/cls_tcindex.c:455
 tcindex_change+0x203/0x2e0 net/sched/cls_tcindex.c:518
 tc_new_tfilter+0xa59/0x20b0 net/sched/cls_api.c:2103
 rtnetlink_rcv_msg+0x810/0xad0 net/core/rtnetlink.c:5431
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2430
 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441739
Code: e8 5c ad 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 3b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd9cd96ed8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441739
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000006cc018 R08: 0000000120080522 R09: 0000000120080522
R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000402600
R13: 0000000000402690 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 1:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 call_usermodehelper_setup+0x98/0x300 kernel/umh.c:386
 kobject_uevent_env+0xcfb/0x11f0 lib/kobject_uevent.c:613
 tty_register_device_attr+0x475/0x6f0 drivers/tty/tty_io.c:3166
 tty_register_device drivers/tty/tty_io.c:3079 [inline]
 tty_register_driver+0x42d/0x800 drivers/tty/tty_io.c:3350
 ttyprintk_init+0x282/0x2cd drivers/char/ttyprintk.c:199
 do_one_initcall+0x10a/0x7d0 init/main.c:1152
 do_initcall_level init/main.c:1225 [inline]
 do_initcalls init/main.c:1241 [inline]
 do_basic_setup init/main.c:1261 [inline]
 kernel_init_freeable+0x501/0x5ae init/main.c:1445
 kernel_init+0xd/0x1bb init/main.c:1352
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 2511:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 call_usermodehelper_freeinfo kernel/umh.c:48 [inline]
 umh_complete kernel/umh.c:62 [inline]
 umh_complete+0x81/0x90 kernel/umh.c:51
 call_usermodehelper_exec_async+0x459/0x710 kernel/umh.c:122
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8880a1cfe600
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 48 bytes inside of
 192-byte region [ffff8880a1cfe600, ffff8880a1cfe6c0)
The buggy address belongs to the page:
page:ffffea0002873f80 refcount:1 mapcount:0 mapping:ffff8880aa000000 index:0xffff8880a1cfef00
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002882508 ffff8880aa001138 ffff8880aa000000
raw: ffff8880a1cfef00 ffff8880a1cfe000 000000010000000a 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a1cfe500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a1cfe580: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a1cfe600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880a1cfe680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880a1cfe700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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