==================================================================
BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x720/0x7f4 drivers/tty/n_gsm.c:2906
Read of size 4 at addr ffff00013049300c by task syz-executor.4/8507

CPU: 1 PID: 8507 Comm: syz-executor.4 Not tainted 6.3.0-rc7-syzkaller-g14f8db1c0f9a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 __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+0x20/0x2c 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+0x4c/0x15c 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 8499:
 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+0x70/0x88 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+0x4c/0x15c 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 8499:
 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+0x2a8/0x49c mm/slub.c:3800
 kfree+0xb8/0x19c 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+0x4c/0x15c 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
 insert_work+0x64/0x384 kernel/workqueue.c:1361
 __queue_work+0xd3c/0x1374 kernel/workqueue.c:1524
 rcu_work_rcufn+0x74/0x8c kernel/workqueue.c:1761
 rcu_do_batch kernel/rcu/tree.c:2112 [inline]
 rcu_core+0x800/0x1aa4 kernel/rcu/tree.c:2372
 rcu_core_si+0x10/0x1c kernel/rcu/tree.c:2389
 __do_softirq+0x2d0/0xd54 kernel/softirq.c:571

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+0x104/0xaf4 kernel/rcu/tree.c:2736
 call_rcu_hurry include/linux/rcupdate.h:116 [inline]
 queue_rcu_work+0x84/0xcc kernel/workqueue.c:1781
 tcf_queue_work+0xd8/0xf0 net/sched/cls_api.c:330
 fl_change+0x1310/0x17f8 net/sched/cls_flower.c:2326
 tc_new_tfilter+0xe38/0x1614 net/sched/cls_api.c:2310
 rtnetlink_rcv_msg+0x780/0xdb8 net/core/rtnetlink.c:6172
 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2577
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6199
 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
 netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365
 netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1942
 sock_sendmsg_nosec net/socket.c:724 [inline]
 sock_sendmsg net/socket.c:747 [inline]
 ____sys_sendmsg+0x568/0x81c net/socket.c:2501
 ___sys_sendmsg net/socket.c:2555 [inline]
 __sys_sendmmsg+0x318/0x7d8 net/socket.c:2641
 __do_sys_sendmmsg net/socket.c:2670 [inline]
 __se_sys_sendmmsg net/socket.c:2667 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2667
 __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+0x4c/0x15c 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

The buggy address belongs to the object at ffff000130493000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 12 bytes inside of
 freed 2048-byte region [ffff000130493000, ffff000130493800)

The buggy address belongs to the physical page:
page:0000000010920fac refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x170490
head:0000000010920fac 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:
 ffff000130492f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff000130492f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff000130493000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff000130493080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff000130493100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
list_add corruption. prev is NULL.
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:24!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 8507 Comm: syz-executor.4 Tainted: G    B              6.3.0-rc7-syzkaller-g14f8db1c0f9a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __list_add_valid+0xcc/0x110 lib/list_debug.c:23
lr : __list_add_valid+0xcc/0x110 lib/list_debug.c:23
sp : ffff800022ec7840
x29: ffff800022ec7840 x28: ffff0000d734f914 x27: ffff000133fd6a18
x26: ffff000133fd6a10 x25: dfff800000000000 x24: 0000000000000000
x23: 0000000000000000 x22: ffff000133fd69c8 x21: ffff0000d734f900
x20: 1fffe000267fad43 x19: ffff000133fd6600 x18: 1fffe00036855db6
x17: 0000000000000000 x16: ffff8000123165a4 x15: 0000000000000002
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001
x11: 0000000000000001 x10: 0000000000000000 x9 : 5cd3bb66ecc94500
x8 : 5cd3bb66ecc94500 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff800022ec7158 x4 : ffff800015d5c8c0 x3 : ffff800008583b68
x2 : 0000000000000001 x1 : 0000000100000001 x0 : 0000000000000022
Call trace:
 __list_add_valid+0xcc/0x110 lib/list_debug.c:23
 __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+0x4c/0x15c 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: d4210000 d003f500 91110000 95e13705 (d4210000) 
---[ end trace 0000000000000000 ]---