================================================================== BUG: KASAN: use-after-free in gsm_cleanup_mux+0x76a/0x850 drivers/tty/n_gsm.c:2397 Read of size 4 at addr ffff88814b40700c by task syz-executor192/3507 CPU: 1 PID: 3507 Comm: syz-executor192 Not tainted 5.15.118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description+0x63/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x16b/0x1c0 mm/kasan/report.c:451 gsm_cleanup_mux+0x76a/0x850 drivers/tty/n_gsm.c:2397 gsm_config drivers/tty/n_gsm.c:2653 [inline] gsmld_ioctl+0xaae/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f5d05d7ac69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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:00007f5d05d0b318 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5d05e024d8 RCX: 00007f5d05d7ac69 RDX: 0000000020000040 RSI: 00000000404c4701 RDI: 0000000000000004 RBP: 00007f5d05e024d0 R08: 00007f5d05d0b700 R09: 0000000000000000 R10: 00007f5d05d0b700 R11: 0000000000000246 R12: 00007f5d05dd008c R13: 00007ffda9f25b2f R14: 00007f5d05d0b400 R15: 0000000000022000 Allocated by task 3501: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc+0xba/0xf0 mm/kasan/common.c:513 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x143/0x290 mm/slub.c:3247 kmalloc include/linux/slab.h:591 [inline] kzalloc include/linux/slab.h:721 [inline] gsm_dlci_alloc+0x53/0x3a0 drivers/tty/n_gsm.c:1932 gsm_activate_mux+0x1c/0x330 drivers/tty/n_gsm.c:2438 gsm_config drivers/tty/n_gsm.c:2677 [inline] gsmld_ioctl+0xd46/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 3501: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kfree+0xf1/0x270 mm/slub.c:4559 dlci_put drivers/tty/n_gsm.c:1988 [inline] gsm_dlci_release drivers/tty/n_gsm.c:2021 [inline] gsm_cleanup_mux+0x574/0x850 drivers/tty/n_gsm.c:2415 gsm_config drivers/tty/n_gsm.c:2653 [inline] gsmld_ioctl+0xaae/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88814b407000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 12 bytes inside of 2048-byte region [ffff88814b407000, ffff88814b407800) The buggy address belongs to the page: page:ffffea00052d0000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14b400 head:ffffea00052d0000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff) raw: 057ff00000010200 dead000000000100 dead000000000122 ffff888011c42000 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 1, ts 11595371377, free_ts 0 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159 __alloc_pages+0x272/0x700 mm/page_alloc.c:5421 alloc_page_interleave+0x22/0x1c0 mm/mempolicy.c:2031 alloc_slab_page mm/slub.c:1775 [inline] allocate_slab mm/slub.c:1912 [inline] new_slab+0xbb/0x4b0 mm/slub.c:1975 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008 __slab_alloc mm/slub.c:3095 [inline] slab_alloc_node mm/slub.c:3186 [inline] __kmalloc_node_track_caller+0x1f6/0x390 mm/slub.c:4958 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x12c/0x590 net/core/skbuff.c:427 alloc_skb include/linux/skbuff.h:1167 [inline] nlmsg_new include/net/netlink.h:953 [inline] rtmsg_ifinfo_build_skb+0x81/0x180 net/core/rtnetlink.c:3830 rtmsg_ifinfo_event net/core/rtnetlink.c:3866 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3875 register_netdevice+0x13ae/0x1700 net/core/dev.c:10376 register_netdev+0x37/0x50 net/core/dev.c:10455 nr_proto_init+0x16f/0x822 net/netrom/af_netrom.c:1419 do_one_initcall+0x22b/0x7a0 init/main.c:1306 do_initcall_level+0x157/0x207 init/main.c:1379 do_initcalls+0x49/0x86 init/main.c:1395 kernel_init_freeable+0x43c/0x5c5 init/main.c:1619 page_owner free stack trace missing Memory state around the buggy address: ffff88814b406f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88814b406f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88814b407000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88814b407080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88814b407100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================