==================================================================
BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x720/0x7f4 drivers/tty/n_gsm.c:2906
Read of size 4 at addr ffff0000d73e200c by task syz-executor.0/6534

CPU: 1 PID: 6534 Comm: syz-executor.0 Not tainted 6.3.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:319 [inline]
 print_report+0x174/0x514 mm/kasan/report.c:430
 kasan_report+0xd4/0x130 mm/kasan/report.c:536
 __asan_report_load4_noabort+0x2c/0x38 mm/kasan/report_generic.c:380
 gsm_cleanup_mux+0x720/0x7f4 drivers/tty/n_gsm.c:2906
 gsm_config drivers/tty/n_gsm.c:3180 [inline]
 gsmld_ioctl+0xe28/0x1a7c drivers/tty/n_gsm.c:3571
 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2786
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Allocated by task 6529:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x7c mm/kasan/common.c:52
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:510
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:196 [inline]
 kmalloc_trace+0x7c/0x94 mm/slab_common.c:1066
 kmalloc include/linux/slab.h:580 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 gsm_dlci_alloc+0x64/0x53c drivers/tty/n_gsm.c:2472
 gsm_activate_mux+0x30/0x268 drivers/tty/n_gsm.c:2954
 gsm_config drivers/tty/n_gsm.c:3208 [inline]
 gsmld_ioctl+0x1098/0x1a7c drivers/tty/n_gsm.c:3571
 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2786
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Freed by task 6529:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x7c mm/kasan/common.c:52
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:521
 ____kasan_slab_free+0x144/0x1c0 mm/kasan/common.c:236
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:244
 kasan_slab_free include/linux/kasan.h:162 [inline]
 slab_free_hook mm/slub.c:1781 [inline]
 slab_free_freelist_hook mm/slub.c:1807 [inline]
 slab_free mm/slub.c:3787 [inline]
 __kmem_cache_free+0x2c0/0x4b4 mm/slub.c:3800
 kfree+0x104/0x228 mm/slab_common.c:1019
 gsm_dlci_free+0x11c/0x168 drivers/tty/n_gsm.c:2525
 tty_port_destructor drivers/tty/tty_port.c:296 [inline]
 kref_put include/linux/kref.h:65 [inline]
 tty_port_put+0xfc/0x190 drivers/tty/tty_port.c:311
 dlci_put drivers/tty/n_gsm.c:2535 [inline]
 gsm_dlci_release drivers/tty/n_gsm.c:2568 [inline]
 gsm_cleanup_mux+0x4ac/0x7f4 drivers/tty/n_gsm.c:2928
 gsm_config drivers/tty/n_gsm.c:3180 [inline]
 gsmld_ioctl+0xe28/0x1a7c drivers/tty/n_gsm.c:3571
 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2786
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Last potentially related work creation:
 kasan_save_stack+0x40/0x6c mm/kasan/common.c:45
 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:491
 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:501
 __call_rcu_common kernel/rcu/tree.c:2622 [inline]
 call_rcu+0x104/0xb38 kernel/rcu/tree.c:2736
 netlink_release+0x12c0/0x1818 net/netlink/af_netlink.c:828
 __sock_release net/socket.c:651 [inline]
 sock_close+0xb8/0x1fc net/socket.c:1393
 __fput+0x30c/0x7bc fs/file_table.c:321
 ____fput+0x20/0x30 fs/file_table.c:349
 task_work_run+0x240/0x2f0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2180/0x3c90 arch/arm64/kernel/signal.c:1302
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

Second to last potentially related work creation:
 kasan_save_stack+0x40/0x6c mm/kasan/common.c:45
 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:491
 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:501
 __call_rcu_common kernel/rcu/tree.c:2622 [inline]
 call_rcu+0x104/0xb38 kernel/rcu/tree.c:2736
 netlink_release+0x12c0/0x1818 net/netlink/af_netlink.c:828
 __sock_release net/socket.c:651 [inline]
 sock_close+0xb8/0x1fc net/socket.c:1393
 __fput+0x30c/0x7bc fs/file_table.c:321
 ____fput+0x20/0x30 fs/file_table.c:349
 task_work_run+0x240/0x2f0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2180/0x3c90 arch/arm64/kernel/signal.c:1302
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591

The buggy address belongs to the object at ffff0000d73e2000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 12 bytes inside of
 freed 2048-byte region [ffff0000d73e2000, ffff0000d73e2800)

The buggy address belongs to the physical page:
page:00000000203b3f5b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1173e0
head:00000000203b3f5b order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 ffff0000c0002900 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d73e1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d73e1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d73e2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff0000d73e2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d73e2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
list_add corruption. prev->next should be next (ffff0000c1b20010), but was 913ae1299006c869. (prev=ffff8000083209a4).
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:32!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 6534 Comm: syz-executor.0 Tainted: G    B              6.3.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __list_add_valid+0x10c/0x110 lib/list_debug.c:30
lr : __list_add_valid+0x10c/0x110 lib/list_debug.c:30
sp : ffff80001e437840
x29: ffff80001e437840 x28: ffff0000e32a8414 x27: ffff0000c1b20018
x26: ffff0000c1b20010 x25: dfff800000000000 x24: ffff8000083209a4
x23: dfff800000000000 x22: ffff0000c1b20018 x21: ffff0000e32a8400
x20: ffff8000083209a4 x19: ffff0000c1b20010 x18: 1fffe000368995b6
x17: 3031303032623163 x16: ffff80001246250c x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001
x11: ff80800008357cc8 x10: 0000000000000000 x9 : e98344e190345a00
x8 : e98344e190345a00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff80001e437158 x4 : ffff800015dc52c0 x3 : ffff80000859c514
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 0000000000000075
Call trace:
 __list_add_valid+0x10c/0x110 lib/list_debug.c:30
 __list_add include/linux/list.h:69 [inline]
 list_add_tail include/linux/list.h:102 [inline]
 gsm_send+0x350/0x604 drivers/tty/n_gsm.c:831
 gsm_command drivers/tty/n_gsm.c:894 [inline]
 gsm_dlci_begin_close drivers/tty/n_gsm.c:2340 [inline]
 gsm_cleanup_mux+0x1a0/0x7f4 drivers/tty/n_gsm.c:2907
 gsm_config drivers/tty/n_gsm.c:3180 [inline]
 gsmld_ioctl+0xe28/0x1a7c drivers/tty/n_gsm.c:3571
 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2786
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
Code: 91068000 aa1303e1 aa1403e3 95e2df94 (d4210000) 
---[ end trace 0000000000000000 ]---