==================================================================
BUG: KASAN: use-after-free in sixpack_close+0x236/0x270 drivers/net/hamradio/6pack.c:678
Read of size 8 at addr ffff88807595ec90 by task syz-executor.0/26735

CPU: 1 PID: 26735 Comm: syz-executor.0 Not tainted 5.15.0-next-20211112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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/0x320 mm/kasan/report.c:247
 __kasan_report mm/kasan/report.c:433 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
 sixpack_close+0x236/0x270 drivers/net/hamradio/6pack.c:678
 tty_ldisc_close+0x110/0x190 drivers/tty/tty_ldisc.c:474
 tty_set_ldisc+0x214/0x680 drivers/tty/tty_ldisc.c:573
 tiocsetd drivers/tty/tty_io.c:2455 [inline]
 tty_ioctl+0xae0/0x1670 drivers/tty/tty_io.c:2741
 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
RIP: 0033:0x7fcf6a4c6ae9
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:00007fcf67a3c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcf6a5d9f60 RCX: 00007fcf6a4c6ae9
RDX: 0000000020000000 RSI: 0000000000005423 RDI: 0000000000000003
RBP: 00007fcf6a520f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff6b9b9ccf R14: 00007fcf67a3c300 R15: 0000000000022000
 </TASK>

Allocated by task 26731:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:522
 kmalloc_node include/linux/slab.h:613 [inline]
 kvmalloc_node+0x61/0x120 mm/util.c:587
 kvmalloc include/linux/slab.h:741 [inline]
 kvzalloc include/linux/slab.h:749 [inline]
 alloc_netdev_mqs+0x98/0xec0 net/core/dev.c:10828
 sixpack_open+0xfa/0xa50 drivers/net/hamradio/6pack.c:558
 tty_ldisc_open+0x9b/0x110 drivers/tty/tty_ldisc.c:449
 tty_set_ldisc+0x2f1/0x680 drivers/tty/tty_ldisc.c:579
 tiocsetd drivers/tty/tty_io.c:2455 [inline]
 tty_ioctl+0xae0/0x1670 drivers/tty/tty_io.c:2741
 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

Freed by task 26735:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749
 slab_free mm/slub.c:3513 [inline]
 kfree+0xf6/0x560 mm/slub.c:4561
 kvfree+0x42/0x50 mm/util.c:620
 device_release+0x9f/0x240 drivers/base/core.c:2230
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c8/0x540 lib/kobject.c:753
 netdev_run_todo+0x75a/0xa80 net/core/dev.c:10638
 sixpack_close+0x184/0x270 drivers/net/hamradio/6pack.c:675
 tty_ldisc_close+0x110/0x190 drivers/tty/tty_ldisc.c:474
 tty_set_ldisc+0x214/0x680 drivers/tty/tty_ldisc.c:573
 tiocsetd drivers/tty/tty_io.c:2455 [inline]
 tty_ioctl+0xae0/0x1670 drivers/tty/tty_io.c:2741
 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 ffff88807595e000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 3216 bytes inside of
 4096-byte region [ffff88807595e000, ffff88807595f000)
The buggy address belongs to the page:
page:ffffea0001d65600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75958
head:ffffea0001d65600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0001383c00 dead000000000002 ffff888010c4c280
raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2970, ts 1065088144790, free_ts 1065058697812
 prep_new_page mm/page_alloc.c:2418 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369
 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191
 alloc_slab_page mm/slub.c:1793 [inline]
 allocate_slab mm/slub.c:1930 [inline]
 new_slab+0x32d/0x4a0 mm/slub.c:1993
 ___slab_alloc+0x918/0xfe0 mm/slub.c:3022
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3109
 slab_alloc_node mm/slub.c:3200 [inline]
 __kmalloc_node+0x2cb/0x390 mm/slub.c:4467
 kmalloc_node include/linux/slab.h:613 [inline]
 kvmalloc_node+0x61/0x120 mm/util.c:587
 kvmalloc include/linux/slab.h:741 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x7e7/0x1240 fs/seq_file.c:210
 kernfs_fop_read_iter+0x44f/0x5f0 fs/kernfs/file.c:241
 call_read_iter include/linux/fs.h:2156 [inline]
 new_sync_read+0x421/0x6e0 fs/read_write.c:400
 vfs_read+0x35c/0x600 fs/read_write.c:481
 ksys_read+0x12d/0x250 fs/read_write.c:619
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1338 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389
 free_unref_page_prepare mm/page_alloc.c:3309 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3388
 qlink_free mm/kasan/quarantine.c:146 [inline]
 qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:3234 [inline]
 slab_alloc mm/slub.c:3242 [inline]
 kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
 getname_flags include/linux/audit.h:323 [inline]
 getname+0x8e/0xd0 fs/namei.c:217
 do_sys_openat2+0xf5/0x4d0 fs/open.c:1206
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_open fs/open.c:1236 [inline]
 __se_sys_open fs/open.c:1232 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1232
 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

Memory state around the buggy address:
 ffff88807595eb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807595ec00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807595ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88807595ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807595ed80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================