================================================================== BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x799/0x810 drivers/tty/n_gsm.c:2906 Read of size 4 at addr ffff888078e0200c by task syz-executor.2/10313 CPU: 0 PID: 10313 Comm: syz-executor.2 Not tainted 6.3.0-rc2-syzkaller-00050-g9c1bec9c0b08 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:319 print_report mm/kasan/report.c:430 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:536 gsm_cleanup_mux+0x799/0x810 drivers/tty/n_gsm.c:2906 gsm_config drivers/tty/n_gsm.c:3180 [inline] gsmld_ioctl+0x819/0x13a0 drivers/tty/n_gsm.c:3571 tty_ioctl+0x80b/0x16e0 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] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f087f48c0f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0880272168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f087f5ac120 RCX: 00007f087f48c0f9 RDX: 0000000020000040 RSI: 00000000404c4701 RDI: 0000000000000004 RBP: 00007f087f4e7b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f087f6cfb1f R14: 00007f0880272300 R15: 0000000000022000 Allocated by task 10307: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] ____kasan_kmalloc mm/kasan/common.c:333 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:580 [inline] kzalloc include/linux/slab.h:720 [inline] gsm_dlci_alloc+0x46/0x7d0 drivers/tty/n_gsm.c:2472 gsm_activate_mux drivers/tty/n_gsm.c:2954 [inline] gsm_config drivers/tty/n_gsm.c:3208 [inline] gsmld_ioctl+0xbad/0x13a0 drivers/tty/n_gsm.c:3571 tty_ioctl+0x80b/0x16e0 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] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 10310: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:521 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807 slab_free mm/slub.c:3787 [inline] __kmem_cache_free+0xaf/0x2d0 mm/slub.c:3800 tty_port_destructor drivers/tty/tty_port.c:296 [inline] kref_put include/linux/kref.h:65 [inline] tty_port_put+0x15c/0x1c0 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+0x30a/0x810 drivers/tty/n_gsm.c:2928 gsm_config drivers/tty/n_gsm.c:3180 [inline] gsmld_ioctl+0x819/0x13a0 drivers/tty/n_gsm.c:3571 tty_ioctl+0x80b/0x16e0 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] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Last potentially related work creation: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:491 __call_rcu_common.constprop.0+0x99/0x7e0 kernel/rcu/tree.c:2622 netlink_release+0xcde/0x1e40 net/netlink/af_netlink.c:828 __sock_release+0xcd/0x290 net/socket.c:653 sock_close+0x1c/0x20 net/socket.c:1395 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd Second to last potentially related work creation: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:491 __call_rcu_common.constprop.0+0x99/0x7e0 kernel/rcu/tree.c:2622 netlink_release+0xcde/0x1e40 net/netlink/af_netlink.c:828 __sock_release+0xcd/0x290 net/socket.c:653 sock_close+0x1c/0x20 net/socket.c:1395 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xad3/0x2960 kernel/exit.c:869 do_group_exit+0xd4/0x2a0 kernel/exit.c:1019 __do_sys_exit_group kernel/exit.c:1030 [inline] __se_sys_exit_group kernel/exit.c:1028 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1028 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888078e02000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 12 bytes inside of freed 2048-byte region [ffff888078e02000, ffff888078e02800) The buggy address belongs to the physical page: page:ffffea0001e38000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78e00 head:ffffea0001e38000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffff888012442000 ffffea0001d60800 dead000000000002 raw: 0000000000000000 0000000000080008 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 5130, tgid 5130 (syz-executor.1), ts 176846105066, free_ts 175365424382 prep_new_page mm/page_alloc.c:2552 [inline] get_page_from_freelist+0x1190/0x2e20 mm/page_alloc.c:4325 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:5591 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2283 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x390 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3193 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292 __slab_alloc_node mm/slub.c:3345 [inline] slab_alloc_node mm/slub.c:3442 [inline] __kmem_cache_alloc_node+0x136/0x320 mm/slub.c:3491 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1061 kmalloc include/linux/slab.h:580 [inline] rtnl_newlink+0x4a/0xa0 net/core/rtnetlink.c:3666 rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6174 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2574 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 __sys_sendto+0x23a/0x340 net/socket.c:2142 __do_sys_sendto net/socket.c:2154 [inline] __se_sys_sendto net/socket.c:2150 [inline] __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2150 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1453 [inline] free_pcp_prepare+0x5d5/0xa50 mm/page_alloc.c:1503 free_unref_page_prepare mm/page_alloc.c:3387 [inline] free_unref_page+0x1d/0x490 mm/page_alloc.c:3482 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2637 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x192/0x220 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slub.c:3452 [inline] kmem_cache_alloc_node+0x185/0x3e0 mm/slub.c:3497 __alloc_skb+0x288/0x330 net/core/skbuff.c:596 alloc_skb include/linux/skbuff.h:1277 [inline] nlmsg_new include/net/netlink.h:1003 [inline] netlink_ack+0x357/0x1360 net/netlink/af_netlink.c:2511 netlink_rcv_skb+0x34f/0x440 net/netlink/af_netlink.c:2580 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 __sys_sendto+0x23a/0x340 net/socket.c:2142 __do_sys_sendto net/socket.c:2154 [inline] __se_sys_sendto net/socket.c:2150 [inline] __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2150 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 Memory state around the buggy address: ffff888078e01f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888078e01f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888078e02000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888078e02080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888078e02100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================