================================================================== BUG: KASAN: use-after-free in rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] BUG: KASAN: use-after-free in rfcomm_dlc_exists+0x17d/0x1a0 net/bluetooth/rfcomm/core.c:549 Read of size 1 at addr ffff8880a4f5d704 by task syz-executor.4/24603 CPU: 0 PID: 24603 Comm: syz-executor.4 Not tainted 4.19.88-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] rfcomm_dlc_exists+0x17d/0x1a0 net/bluetooth/rfcomm/core.c:549 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:413 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0x9c8/0x1c90 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x90/0xb0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0xd8/0x2f0 net/socket.c:950 sock_ioctl+0x325/0x610 net/socket.c:1074 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f630e90fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f630e9106d4 R13: 00000000004c31d8 R14: 00000000004d8458 R15: 00000000ffffffff Allocated by task 15379: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:137 __alloc_skb+0x10b/0x5f0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] sock_wmalloc+0xd9/0x120 net/core/sock.c:1937 unix_stream_connect+0x20e/0x10ba net/unix/af_unix.c:1242 __sys_connect+0x264/0x330 net/socket.c:1663 __do_sys_connect net/socket.c:1674 [inline] __se_sys_connect net/socket.c:1671 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1671 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7738: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x99/0xc0 net/core/skbuff.c:554 skb_release_data+0x619/0x8d0 net/core/skbuff.c:574 skb_release_all+0x4d/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb net/core/skbuff.c:705 [inline] consume_skb+0xe2/0x390 net/core/skbuff.c:699 skb_free_datagram+0x1b/0x100 net/core/datagram.c:329 unix_accept+0x1fd/0x5b0 net/unix/af_unix.c:1451 __sys_accept4+0x34e/0x6a0 net/socket.c:1589 __do_sys_accept net/socket.c:1630 [inline] __se_sys_accept net/socket.c:1627 [inline] __x64_sys_accept+0x75/0xb0 net/socket.c:1627 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a4f5d5c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 324 bytes inside of 512-byte region [ffff8880a4f5d5c0, ffff8880a4f5d7c0) The buggy address belongs to the page: page:ffffea000293d740 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff8880a4f5dd40 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea0002239e48 ffffea0001c67cc8 ffff88812c31c940 raw: ffff8880a4f5dd40 ffff8880a4f5d0c0 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a4f5d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4f5d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a4f5d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a4f5d780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880a4f5d800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================