================================================================== BUG: KASAN: slab-use-after-free in hci_uart_write_work+0x82d/0x960 drivers/bluetooth/hci_ldisc.c:165 Read of size 4 at addr ffff8880412b46b0 by task kworker/3:1/57 CPU: 3 UID: 0 PID: 57 Comm: kworker/3:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: events hci_uart_write_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 hci_uart_write_work+0x82d/0x960 drivers/bluetooth/hci_ldisc.c:165 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Allocated by task 6029: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x298/0x800 mm/slub.c:5315 __alloc_skb+0x156/0x410 net/core/skbuff.c:679 alloc_skb include/linux/skbuff.h:1383 [inline] bcsp_prepare_pkt+0xe0/0xae0 drivers/bluetooth/hci_bcsp.c:218 bcsp_dequeue+0x237/0x4b0 drivers/bluetooth/hci_bcsp.c:308 hci_uart_dequeue drivers/bluetooth/hci_ldisc.c:107 [inline] hci_uart_write_work+0x4e3/0x960 drivers/bluetooth/hci_ldisc.c:161 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 7533: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x2d8/0x770 mm/slub.c:6781 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1130 __kfree_skb net/core/skbuff.c:1197 [inline] sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1234 kfree_skb_reason include/linux/skbuff.h:1322 [inline] kfree_skb include/linux/skbuff.h:1331 [inline] hci_uart_flush+0xa7/0x5d0 drivers/bluetooth/hci_ldisc.c:235 hci_uart_close+0x1d/0xa0 drivers/bluetooth/hci_ldisc.c:268 hci_uart_tty_close+0xb0/0x2d0 drivers/bluetooth/hci_ldisc.c:545 tty_ldisc_close+0x114/0x1a0 drivers/tty/tty_ldisc.c:455 tty_ldisc_kill+0x8e/0x150 drivers/tty/tty_ldisc.c:613 tty_ldisc_hangup+0x365/0x730 drivers/tty/tty_ldisc.c:729 __tty_hangup.part.0+0x3fe/0x8c0 drivers/tty/tty_io.c:621 __tty_hangup drivers/tty/tty_io.c:688 [inline] tty_vhangup drivers/tty/tty_io.c:691 [inline] tty_vhangup drivers/tty/tty_io.c:688 [inline] tty_ioctl+0x1057/0x1650 drivers/tty/tty_io.c:2732 tty_compat_ioctl+0xb9/0x4d0 drivers/tty/tty_io.c:2958 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff8880412b4640 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 112 bytes inside of freed 240-byte region [ffff8880412b4640, ffff8880412b4730) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x412b4 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88804fbc5601 flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801c3bc8c0 ffffea00017cfd00 dead000000000002 raw: 0000000000000000 0000000080190019 00000000f5000000 ffff88804fbc5601 head: 04fff00000000040 ffff88801c3bc8c0 ffffea00017cfd00 dead000000000002 head: 0000000000000000 0000000080190019 00000000f5000000 ffff88804fbc5601 head: 04fff00000000001 ffffea000104ad01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5649, tgid 5649 (dhcpcd), ts 35218663250, free_ts 29054325416 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4656 __kmem_cache_alloc_bulk+0x1fb/0x6c0 mm/slub.c:7431 kmem_cache_alloc_bulk_noprof+0x4e1/0x800 mm/slub.c:7497 napi_skb_cache_get+0x6ac/0x900 net/core/skbuff.c:291 __alloc_skb+0x2aa/0x410 net/core/skbuff.c:668 napi_alloc_skb+0x44b/0x820 net/core/skbuff.c:832 napi_get_frags net/core/gro.c:681 [inline] napi_get_frags+0x5b/0x140 net/core/gro.c:676 napi_get_frags_check net/core/dev.c:7487 [inline] netif_napi_add_weight_locked+0x694/0xcd0 net/core/dev.c:7527 netif_napi_add_weight include/linux/netdevice.h:2814 [inline] lapbeth_new_device drivers/net/wan/lapbether.c:417 [inline] lapbeth_device_event+0x5a1/0xc80 drivers/net/wan/lapbether.c:462 notifier_call_chain+0xbc/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2230 page last free pid 5435 tgid 5435 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x130/0x170 mm/slub.c:3886 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x2f6/0x910 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] tomoyo_realpath_from_path+0xc2/0x6e0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x274/0x460 security/tomoyo/file.c:822 security_inode_getattr+0x116/0x290 security/security.c:1869 vfs_getattr fs/stat.c:259 [inline] vfs_fstat+0x4b/0xe0 fs/stat.c:281 __do_sys_newfstat+0x87/0x100 fs/stat.c:555 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880412b4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ffff8880412b4600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff8880412b4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880412b4700: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc ffff8880412b4780: fa fb fb fb 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