================================================================== BUG: KASAN: use-after-free in rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] BUG: KASAN: use-after-free in __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:396 [inline] BUG: KASAN: use-after-free in rfcomm_dlc_open+0xc85/0xd60 net/bluetooth/rfcomm/core.c:431 Read of size 1 at addr ffff8880a9b66644 by task syz-executor.0/18004 CPU: 0 PID: 18004 Comm: syz-executor.0 Not tainted 5.2.0-rc1+ #1 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129 rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:396 [inline] rfcomm_dlc_open+0xc85/0xd60 net/bluetooth/rfcomm/core.c:431 rfcomm_sock_connect+0x38a/0x4b0 net/bluetooth/rfcomm/sock.c:416 __sys_connect+0x264/0x330 net/socket.c:1840 __do_sys_connect net/socket.c:1851 [inline] __se_sys_connect net/socket.c:1848 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1848 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f71d1226c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279 RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f71d12276d4 R13: 00000000004bf6e6 R14: 00000000004d0b70 R15: 00000000ffffffff Allocated by task 16506: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 __do_kmalloc_node mm/slab.c:3620 [inline] __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3634 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:142 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1058 [inline] sock_wmalloc+0xd9/0x120 net/core/sock.c:2077 pppol2tp_sendmsg+0x23b/0x6b0 net/l2tp/l2tp_ppp.c:302 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:671 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2292 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2387 __do_sys_sendmmsg net/socket.c:2416 [inline] __se_sys_sendmmsg net/socket.c:2413 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2413 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 16506: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kfree+0xcf/0x220 mm/slab.c:3755 skb_free_head+0x93/0xb0 net/core/skbuff.c:592 pskb_expand_head+0x2bd/0xe00 net/core/skbuff.c:1534 __skb_cow include/linux/skbuff.h:3037 [inline] skb_cow_head include/linux/skbuff.h:3071 [inline] l2tp_xmit_skb+0xe4e/0x13e0 net/l2tp/l2tp_core.c:1072 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:329 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:671 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2292 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2387 __do_sys_sendmmsg net/socket.c:2416 [inline] __se_sys_sendmmsg net/socket.c:2413 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2413 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a9b66500 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 324 bytes inside of 512-byte region [ffff8880a9b66500, ffff8880a9b66700) The buggy address belongs to the page: page:ffffea0002a6d980 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0xffff8880a9b66000 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00023d3148 ffffea0001b04348 ffff8880aa400940 raw: ffff8880a9b66000 ffff8880a9b66000 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a9b66500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a9b66580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a9b66600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a9b66680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a9b66700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 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