Hello, syzbot found the following issue on: HEAD commit: 2ea35288c83b skbuff: skb_segment, Call zero copy functions.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=17f46d87a80000 kernel config: https://syzkaller.appspot.com/x/.config?x=634e05b4025da9da dashboard link: https://syzkaller.appspot.com/bug?extid=b1b9423479233352b99e compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/d8d28ba7b968/disk-2ea35288.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/12a9f785a85b/vmlinux-2ea35288.xz kernel image: https://storage.googleapis.com/syzbot-assets/d71c4427c061/bzImage-2ea35288.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b1b9423479233352b99e@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: use-after-free in hci_conn_ssp_enabled include/net/bluetooth/hci_core.h:988 [inline] BUG: KASAN: use-after-free in hci_conn_security+0x324/0x990 net/bluetooth/hci_conn.c:2409 Read of size 8 at addr ffff8880784dda70 by task kworker/1:11/12886 CPU: 1 PID: 12886 Comm: kworker/1:11 Not tainted 6.5.0-syzkaller-04006-g2ea35288c83b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Workqueue: events l2cap_info_timeout Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc4/0x620 mm/kasan/report.c:475 kasan_report+0xda/0x110 mm/kasan/report.c:588 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0xef/0x190 mm/kasan/generic.c:187 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hci_conn_ssp_enabled include/net/bluetooth/hci_core.h:988 [inline] hci_conn_security+0x324/0x990 net/bluetooth/hci_conn.c:2409 l2cap_chan_check_security+0x16f/0x320 net/bluetooth/l2cap_core.c:929 l2cap_conn_start+0x59b/0xa40 net/bluetooth/l2cap_core.c:1646 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 </TASK> The buggy address belongs to the physical page: page:ffffea0001e13740 refcount:0 mapcount:0 mapping:0000000000000000 index:0x4 pfn:0x784dd flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000000 0000000000000000 ffffffff00000201 0000000000000000 raw: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 2, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 9825, tgid 9825 (syz-executor.2), ts 251793148654, free_ts 864555377636 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x2d2/0x350 mm/page_alloc.c:1570 prep_new_page mm/page_alloc.c:1577 [inline] get_page_from_freelist+0x10a9/0x31e0 mm/page_alloc.c:3221 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4477 __alloc_pages_node include/linux/gfp.h:237 [inline] alloc_pages_node include/linux/gfp.h:260 [inline] __kmalloc_large_node+0x87/0x1c0 mm/slab_common.c:1126 __do_kmalloc_node mm/slab_common.c:973 [inline] __kmalloc.cold+0xb/0xe0 mm/slab_common.c:998 kmalloc include/linux/slab.h:586 [inline] kzalloc include/linux/slab.h:703 [inline] hci_alloc_dev_priv+0x1d/0x2780 net/bluetooth/hci_core.c:2467 hci_alloc_dev include/net/bluetooth/hci_core.h:1600 [inline] __vhci_create_device+0xf7/0x800 drivers/bluetooth/hci_vhci.c:402 vhci_create_device drivers/bluetooth/hci_vhci.c:475 [inline] vhci_get_user drivers/bluetooth/hci_vhci.c:532 [inline] vhci_write+0x2c7/0x470 drivers/bluetooth/hci_vhci.c:612 call_write_iter include/linux/fs.h:1985 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1161 [inline] free_unref_page_prepare+0x508/0xb90 mm/page_alloc.c:2348 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2443 hci_release_dev+0x4da/0x600 net/bluetooth/hci_core.c:2792 bt_host_release+0x6a/0xb0 net/bluetooth/hci_sysfs.c:93 device_release+0xa1/0x240 drivers/base/core.c:2484 kobject_cleanup lib/kobject.c:682 [inline] kobject_release lib/kobject.c:713 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1f7/0x5b0 lib/kobject.c:730 put_device+0x1f/0x30 drivers/base/core.c:3733 vhci_release+0x87/0x100 drivers/bluetooth/hci_vhci.c:670 __fput+0x3f7/0xa70 fs/file_table.c:384 task_work_run+0x14d/0x240 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa99/0x2a20 kernel/exit.c:874 do_group_exit+0xd4/0x2a0 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff8880784dd900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880784dd980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8880784dda00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8880784dda80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880784ddb00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
