syzbot

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BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0x191/0x1a0 net/bluetooth/l2cap_sock.c:1687
Read of size 8 at addr ffff888035c37188 by task kworker/1:3/5799

CPU: 1 UID: 0 PID: 5799 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: events l2cap_info_timeout
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
 l2cap_sock_ready_cb+0x191/0x1a0 net/bluetooth/l2cap_sock.c:1687
 l2cap_chan_ready net/bluetooth/l2cap_core.c:1247 [inline]
 l2cap_conn_start+0x123/0xb20 net/bluetooth/l2cap_core.c:1513
 l2cap_info_timeout+0x81/0xa0 net/bluetooth/l2cap_core.c:1670
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 12602:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_noprof+0x347/0x9c0 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2245
 sk_alloc+0x36/0xe80 net/core/sock.c:2301
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1e0 net/bluetooth/l2cap_sock.c:1897
 l2cap_sock_create+0x123/0x210 net/bluetooth/l2cap_sock.c:1939
 bt_sock_create+0x185/0x350 net/bluetooth/af_bluetooth.c:135
 __sock_create+0x339/0x860 net/socket.c:1605
 sock_create net/socket.c:1663 [inline]
 __sys_socket_create net/socket.c:1700 [inline]
 __sys_socket+0x14d/0x260 net/socket.c:1747
 __do_sys_socket net/socket.c:1761 [inline]
 __se_sys_socket net/socket.c:1759 [inline]
 __x64_sys_socket+0x72/0xb0 net/socket.c:1759
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12599:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 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:6674 [inline]
 kfree+0x1c7/0x690 mm/slub.c:6882
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x8ab/0xbb0 net/core/sock.c:2384
 sk_destruct+0xc8/0xf0 net/core/sock.c:2412
 __sk_free+0xf4/0x3e0 net/core/sock.c:2423
 sk_free+0x61/0x90 net/core/sock.c:2434
 sock_put include/net/sock.h:1998 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1265 [inline]
 l2cap_sock_kill+0x176/0x310 net/bluetooth/l2cap_sock.c:1250
 l2cap_sock_release+0x1cb/0x280 net/bluetooth/l2cap_sock.c:1438
 __sock_release+0xb3/0x260 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x3ff/0xb40 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x4fe/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888035c37000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 392 bytes inside of
 freed 2048-byte region [ffff888035c37000, ffff888035c37800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888035c37000 pfn:0x35c30
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88813fe27000 ffffea000089a010 ffffea000098a010
raw: ffff888035c37000 0000000000080007 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88813fe27000 ffffea000089a010 ffffea000098a010
head: ffff888035c37000 0000000000080007 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000d70c01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 16556383820, free_ts 14423148272
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240
 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+0x2c4/0x440 mm/slub.c:3302
 ___slab_alloc+0xda3/0x1ca0 mm/slub.c:4656
 __slab_alloc.isra.0+0x63/0x110 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __kmalloc_cache_noprof+0x531/0x810 mm/slub.c:5775
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 ext4_alloc_sbi fs/ext4/super.c:4327 [inline]
 ext4_fill_super+0x19f/0xb3f0 fs/ext4/super.c:5764
 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1691
 vfs_get_tree+0x92/0x320 fs/super.c:1751
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3636 [inline]
 do_new_mount fs/namespace.c:3712 [inline]
 path_mount+0x7d0/0x23c0 fs/namespace.c:4022
 init_mount+0xbd/0x110 fs/init.c:25
 do_mount_root+0x11a/0x2e0 init/do_mounts.c:166
 mount_root_generic+0x1d5/0x420 init/do_mounts.c:205
 mount_block_root init/do_mounts.c:381 [inline]
 mount_root+0x3ad/0x400 init/do_mounts.c:408
page last free pid 10 tgid 10 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973
 vfree.part.0+0x12b/0x9d0 mm/vmalloc.c:3466
 vfree mm/vmalloc.c:3443 [inline]
 delayed_vfree_work+0x8e/0xd0 mm/vmalloc.c:3385
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Memory state around the buggy address:
 ffff888035c37080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035c37100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888035c37180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888035c37200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035c37280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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