================================================================== BUG: KASAN: use-after-free in gsm_cleanup_mux+0x700/0x7d8 drivers/tty/n_gsm.c:2491 Read of size 4 at addr ffff00012ad8600c by task syz-executor.1/7795 CPU: 1 PID: 7795 Comm: syz-executor.1 Not tainted 6.1.30-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 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+0x108/0x170 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x174/0x4c0 mm/kasan/report.c:395 kasan_report+0xd4/0x130 mm/kasan/report.c:495 __asan_report_load4_noabort+0x2c/0x38 mm/kasan/report_generic.c:350 gsm_cleanup_mux+0x700/0x7d8 drivers/tty/n_gsm.c:2491 gsm_config drivers/tty/n_gsm.c:2754 [inline] gsmld_ioctl+0x9d4/0x1384 drivers/tty/n_gsm.c:3117 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2782 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+0x64/0x218 arch/arm64/kernel/syscall.c:206 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 Allocated by task 7794: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1050 kmalloc include/linux/slab.h:553 [inline] kzalloc include/linux/slab.h:689 [inline] gsm_dlci_alloc+0x60/0x340 drivers/tty/n_gsm.c:2064 gsm_activate_mux+0x30/0x268 drivers/tty/n_gsm.c:2538 gsm_config drivers/tty/n_gsm.c:2778 [inline] gsmld_ioctl+0xbc0/0x1384 drivers/tty/n_gsm.c:3117 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2782 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+0x64/0x218 arch/arm64/kernel/syscall.c:206 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 Freed by task 7794: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____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:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook mm/slub.c:1750 [inline] slab_free mm/slub.c:3661 [inline] __kmem_cache_free+0x2c0/0x4b4 mm/slub.c:3674 kfree+0xcc/0x1b8 mm/slab_common.c:1007 gsm_dlci_free+0x11c/0x168 drivers/tty/n_gsm.c:2110 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:2120 [inline] gsm_dlci_release drivers/tty/n_gsm.c:2153 [inline] gsm_cleanup_mux+0x48c/0x7d8 drivers/tty/n_gsm.c:2512 gsm_config drivers/tty/n_gsm.c:2754 [inline] gsmld_ioctl+0x9d4/0x1384 drivers/tty/n_gsm.c:3117 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2782 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+0x64/0x218 arch/arm64/kernel/syscall.c:206 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:45 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 call_rcu+0xfc/0xa40 kernel/rcu/tree.c:2799 netlink_release+0x11c8/0x16f4 net/netlink/af_netlink.c:817 __sock_release net/socket.c:652 [inline] sock_close+0xb8/0x1fc net/socket.c:1370 __fput+0x30c/0x7bc fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 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+0x2144/0x3470 arch/arm64/kernel/signal.c:1132 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 Second to last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:45 __kasan_record_aux_stack+0xcc/0xe8 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 call_rcu+0xfc/0xa40 kernel/rcu/tree.c:2799 netlink_release+0x11c8/0x16f4 net/netlink/af_netlink.c:817 __sock_release net/socket.c:652 [inline] sock_close+0xb8/0x1fc net/socket.c:1370 __fput+0x30c/0x7bc fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x240/0x2f0 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x554/0x1a88 kernel/exit.c:869 do_group_exit+0x194/0x22c kernel/exit.c:1019 get_signal+0x14a0/0x158c kernel/signal.c:2858 do_signal arch/arm64/kernel/signal.c:1076 [inline] do_notify_resume+0x3ac/0x3470 arch/arm64/kernel/signal.c:1129 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 The buggy address belongs to the object at ffff00012ad86000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 12 bytes inside of 2048-byte region [ffff00012ad86000, ffff00012ad86800) The buggy address belongs to the physical page: page:0000000009ce8b61 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16ad80 head:0000000009ce8b61 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc0003240400 dead000000000002 ffff0000c0002900 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff00012ad85f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff00012ad85f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff00012ad86000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff00012ad86080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff00012ad86100: 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: 7795 Comm: syz-executor.1 Tainted: G B 6.1.30-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 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 : ffff80001fde78a0 x29: ffff80001fde78a0 x28: ffff0000d9545314 x27: ffff0000d1bad918 x26: ffff0000d1bad910 x25: dfff800000000000 x24: 0000000000000000 x23: 0000000000000000 x22: ffff0000d1bad8c8 x21: ffff0000d9545300 x20: 1fffe0001a375b23 x19: ffff0000d1bad500 x18: 1fffe000368ba176 x17: 0000000000000000 x16: ffff8000120fc834 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001 x11: ff80800008345658 x10: 0000000000000000 x9 : 13d51953d5095b00 x8 : 13d51953d5095b00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff80001fde71b8 x4 : ffff800015692ac0 x3 : ffff8000085879f4 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:726 gsm_command drivers/tty/n_gsm.c:789 [inline] gsm_dlci_begin_close drivers/tty/n_gsm.c:1933 [inline] gsm_cleanup_mux+0x1a0/0x7d8 drivers/tty/n_gsm.c:2492 gsm_config drivers/tty/n_gsm.c:2754 [inline] gsmld_ioctl+0x9d4/0x1384 drivers/tty/n_gsm.c:3117 tty_ioctl+0x924/0xd8c drivers/tty/tty_io.c:2782 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+0x64/0x218 arch/arm64/kernel/syscall.c:206 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+0x18c/0x190 arch/arm64/kernel/entry.S:581 Code: d4210000 9003e2e0 91178000 95d85f15 (d4210000) ---[ end trace 0000000000000000 ]---