================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:43 [inline] BUG: KASAN: use-after-free in skb_unref include/linux/skbuff.h:1016 [inline] BUG: KASAN: use-after-free in kfree_skb+0x2a/0xb0 net/core/skbuff.c:693 Read of size 4 at addr ffff8880936a5694 by task syz-executor.2/9480 CPU: 1 PID: 9480 Comm: syz-executor.2 Not tainted 5.3.0-rc2+ #59 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+0x1d8/0x2f8 lib/dump_stack.c:113 print_address_description+0x75/0x5b0 mm/kasan/report.c:351 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:482 kasan_report+0x26/0x50 mm/kasan/common.c:612 check_memory_region_inline mm/kasan/generic.c:182 [inline] check_memory_region+0x2cf/0x2e0 mm/kasan/generic.c:192 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] refcount_read include/linux/refcount.h:43 [inline] skb_unref include/linux/skbuff.h:1016 [inline] kfree_skb+0x2a/0xb0 net/core/skbuff.c:693 bcsp_close+0xb1/0xf0 drivers/bluetooth/hci_bcsp.c:748 hci_uart_tty_close+0x201/0x240 drivers/bluetooth/hci_ldisc.c:548 tty_ldisc_close+0x128/0x1a0 drivers/tty/tty_ldisc.c:494 tty_ldisc_kill drivers/tty/tty_ldisc.c:642 [inline] tty_ldisc_release+0x248/0x5c0 drivers/tty/tty_ldisc.c:814 tty_release_struct+0x2a/0xe0 drivers/tty/tty_io.c:1612 tty_release+0xce9/0xfa0 drivers/tty/tty_io.c:1785 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x64c/0x2300 kernel/exit.c:879 do_group_exit+0x15c/0x2b0 kernel/exit.c:983 get_signal+0x51c/0x1dd0 kernel/signal.c:2729 do_signal+0x7b/0x720 arch/x86/kernel/signal.c:815 exit_to_usermode_loop arch/x86/entry/common.c:159 [inline] prepare_exit_to_usermode+0x303/0x580 arch/x86/entry/common.c:194 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:274 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457cf1 Code: 75 14 b8 23 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 d3 fb ff c3 48 83 ec 08 e8 ea 46 00 00 48 89 04 24 b8 23 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 33 47 00 00 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffe4ed27860 EFLAGS: 00000293 ORIG_RAX: 0000000000000023 RAX: 0000000000000000 RBX: 0000000000177fa7 RCX: 0000000000457cf1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffe4ed27870 RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff R10: 00007ffe4ed27960 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000075c9a0 R14: 0000000000760288 R15: ffffffffffffffff Allocated by task 7: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:487 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc_node mm/slab.c:3262 [inline] kmem_cache_alloc_node+0x235/0x280 mm/slab.c:3574 __alloc_skb+0x9f/0x500 net/core/skbuff.c:197 alloc_skb include/linux/skbuff.h:1055 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline] bcsp_recv+0x12e7/0x1720 drivers/bluetooth/hci_bcsp.c:670 hci_uart_tty_receive+0x16b/0x4f0 drivers/bluetooth/hci_ldisc.c:613 tty_ldisc_receive_buf+0x12e/0x170 drivers/tty/tty_buffer.c:465 tty_port_default_receive_buf+0x82/0xb0 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x328/0x560 drivers/tty/tty_buffer.c:533 process_one_work+0x83b/0x1150 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Freed by task 7: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kmem_cache_free+0x81/0xf0 mm/slab.c:3693 kfree_skbmem net/core/skbuff.c:644 [inline] __kfree_skb+0x118/0x170 net/core/skbuff.c:680 kfree_skb+0x6f/0xb0 net/core/skbuff.c:697 bcsp_recv+0x99c/0x1720 drivers/bluetooth/hci_bcsp.c:608 hci_uart_tty_receive+0x16b/0x4f0 drivers/bluetooth/hci_ldisc.c:613 tty_ldisc_receive_buf+0x12e/0x170 drivers/tty/tty_buffer.c:465 tty_port_default_receive_buf+0x82/0xb0 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x328/0x560 drivers/tty/tty_buffer.c:533 process_one_work+0x83b/0x1150 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff8880936a55c0 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 212 bytes inside of 224-byte region [ffff8880936a55c0, ffff8880936a56a0) The buggy address belongs to the page: page:ffffea00024da940 refcount:1 mapcount:0 mapping:ffff88821b6ad700 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000297ca88 ffffea00029ef988 ffff88821b6ad700 raw: 0000000000000000 ffff8880936a50c0 000000010000000c 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880936a5580: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8880936a5600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880936a5680: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880936a5700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880936a5780: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================