================================================================== BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x799/0x810 drivers/tty/n_gsm.c:2906 Read of size 4 at addr ffff888075d7100c by task syz-executor.0/7041 CPU: 1 PID: 7041 Comm: syz-executor.0 Not tainted 6.3.0-rc5-syzkaller-00202-ga79d5c76f705 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 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: 0033:0x7f815fc8c169 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:00007f81609f2168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f815fdac120 RCX: 00007f815fc8c169 RDX: 0000000020000040 RSI: 00000000404c4701 RDI: 0000000000000005 RBP: 00007f815fce7ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f815fecfb1f R14: 00007f81609f2300 R15: 0000000000022000 Allocated by task 7033: 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 7037: 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 net/socket.c:653 [inline] sock_release+0x8b/0x1d0 net/socket.c:681 netlink_kernel_release+0x4f/0x60 net/netlink/af_netlink.c:2129 diag_net_exit+0x38/0x80 net/core/sock_diag.c:328 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 The buggy address belongs to the object at ffff888075d71000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 12 bytes inside of freed 2048-byte region [ffff888075d71000, ffff888075d71800) The buggy address belongs to the physical page: page:ffffea0001d75c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75d70 head:ffffea0001d75c00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffff888012442000 ffffea0000c47400 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 5173, tgid 5173 (kworker/1:6), ts 141390254670, free_ts 138717563623 prep_new_page mm/page_alloc.c:2553 [inline] get_page_from_freelist+0x1190/0x2e20 mm/page_alloc.c:4326 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:5592 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 __do_kmalloc_node mm/slab_common.c:966 [inline] __kmalloc_node_track_caller+0x4f/0x1a0 mm/slab_common.c:987 kmalloc_reserve+0xf0/0x270 net/core/skbuff.c:537 __alloc_skb+0x129/0x330 net/core/skbuff.c:606 alloc_skb include/linux/skbuff.h:1277 [inline] alloc_skb_with_frags+0x97/0x6c0 net/core/skbuff.c:6318 sock_alloc_send_pskb+0x7a7/0x930 net/core/sock.c:2734 sock_alloc_send_skb include/net/sock.h:1860 [inline] mld_newpack.isra.0+0x1b9/0x770 net/ipv6/mcast.c:1748 add_grhead+0x295/0x340 net/ipv6/mcast.c:1851 add_grec+0x1053/0x1610 net/ipv6/mcast.c:1989 mld_send_cr net/ipv6/mcast.c:2115 [inline] mld_ifc_work+0x42c/0xe20 net/ipv6/mcast.c:2653 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1454 [inline] free_pcp_prepare+0x5d5/0xa50 mm/page_alloc.c:1504 free_unref_page_prepare mm/page_alloc.c:3388 [inline] free_unref_page+0x1d/0x490 mm/page_alloc.c:3483 __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+0x17c/0x320 mm/slub.c:3491 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1061 kmalloc include/linux/slab.h:580 [inline] kzalloc include/linux/slab.h:720 [inline] kobject_uevent_env+0x232/0x16c0 lib/kobject_uevent.c:524 __kobject_del+0x160/0x1f0 lib/kobject.c:593 kobject_cleanup lib/kobject.c:672 [inline] kobject_release lib/kobject.c:712 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x2f1/0x4d0 lib/kobject.c:729 netdev_queue_update_kobjects+0x36b/0x4f0 net/core/net-sysfs.c:1761 netif_set_real_num_tx_queues+0x1ba/0x870 net/core/dev.c:2879 veth_init_queues+0xdd/0x190 drivers/net/veth.c:1757 veth_newlink+0x540/0x9d0 drivers/net/veth.c:1877 rtnl_newlink_create net/core/rtnetlink.c:3440 [inline] __rtnl_newlink+0x10c2/0x1840 net/core/rtnetlink.c:3657 Memory state around the buggy address: ffff888075d70f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888075d70f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888075d71000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888075d71080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075d71100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================