================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline] BUG: KASAN: use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1667 [inline] BUG: KASAN: use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:169 [inline] BUG: KASAN: use-after-free in mutex_lock+0x8e/0x1c0 kernel/locking/mutex.c:288 Write of size 8 at addr ffff88810e03ad50 by task syz.1.174/893 CPU: 1 PID: 893 Comm: syz.1.174 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0x10f/0x150 mm/kasan/report.c:444 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1667 [inline] __mutex_trylock_fast kernel/locking/mutex.c:169 [inline] mutex_lock+0x8e/0x1c0 kernel/locking/mutex.c:288 pppol2tp_release+0x178/0x2b0 net/l2tp/l2tp_ppp.c:442 __sock_release net/socket.c:649 [inline] sock_close+0xb8/0x200 net/socket.c:1336 __fput+0x22b/0x900 fs/file_table.c:311 ____fput+0x15/0x20 fs/file_table.c:339 task_work_run+0x127/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:184 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:217 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:310 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8b835d9199 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe8426b3c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007ffe8426b4b0 RCX: 00007f8b835d9199 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000000a1bd R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2d920000 R11: 0000000000000246 R12: 00007ffe8426b4f0 R13: 00007f8b83860fac R14: 000000000000a277 R15: 00007f8b83860fa0 Allocated by task 894: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:433 [inline] ____kasan_kmalloc mm/kasan/common.c:512 [inline] __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521 kasan_kmalloc include/linux/kasan.h:227 [inline] __kmalloc+0x13d/0x2c0 mm/slub.c:4436 kmalloc include/linux/slab.h:624 [inline] kzalloc include/linux/slab.h:750 [inline] l2tp_session_create+0x39/0xb60 net/l2tp/l2tp_core.c:1616 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:772 __sys_connect_file net/socket.c:1923 [inline] __sys_connect+0x3cb/0x450 net/socket.c:1940 __do_sys_connect net/socket.c:1950 [inline] __se_sys_connect net/socket.c:1947 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:1947 x64_sys_call+0x7c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 893: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kfree+0xc4/0x270 mm/slub.c:4588 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline] l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193 l2tp_session_delete+0x3a9/0x4a0 net/l2tp/l2tp_core.c:1589 pppol2tp_release+0x169/0x2b0 net/l2tp/l2tp_ppp.c:439 __sock_release net/socket.c:649 [inline] sock_close+0xb8/0x200 net/socket.c:1336 __fput+0x22b/0x900 fs/file_table.c:311 ____fput+0x15/0x20 fs/file_table.c:339 task_work_run+0x127/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:184 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:217 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:310 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu_common kernel/rcu/tree.c:3011 [inline] call_rcu+0x10b/0xf60 kernel/rcu/tree.c:3129 assoc_array_apply_edit+0x9fb/0xa50 lib/assoc_array.c:1398 __key_link+0xd6/0x120 security/keys/keyring.c:1377 __key_instantiate_and_link+0x23b/0x3c0 security/keys/key.c:460 key_instantiate_and_link+0x385/0x4b0 security/keys/key.c:538 add_master_key_user+0x1c2/0x2a0 fs/crypto/keyring.c:384 add_new_master_key+0x34f/0x5e0 fs/crypto/keyring.c:436 do_add_master_key fs/crypto/keyring.c:506 [inline] add_master_key+0x4a7/0x8b0 fs/crypto/keyring.c:570 fscrypt_add_test_dummy_key+0x11b/0x230 fs/crypto/keyring.c:794 fscrypt_set_test_dummy_encryption+0x2f2/0x6b0 fs/crypto/policy.c:758 f2fs_set_test_dummy_encryption fs/f2fs/super.c:546 [inline] parse_options+0x1d24/0x4790 fs/f2fs/super.c:1095 f2fs_fill_super+0x1f09/0x6dd0 fs/f2fs/super.c:4247 mount_bdev+0x28d/0x3c0 fs/super.c:1411 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4713 legacy_get_tree+0xed/0x190 fs/fs_context.c:611 vfs_get_tree+0x89/0x260 fs/super.c:1541 do_new_mount+0x251/0xb40 fs/namespace.c:3037 path_mount+0x640/0xff0 fs/namespace.c:3367 do_mount fs/namespace.c:3380 [inline] __do_sys_mount fs/namespace.c:3588 [inline] __se_sys_mount+0x320/0x390 fs/namespace.c:3565 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3565 x64_sys_call+0x6bf/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff88810e03ac00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 336 bytes inside of 512-byte region [ffff88810e03ac00, ffff88810e03ae00) The buggy address belongs to the page: page:ffffea0004380e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88810e039c00 pfn:0x10e038 head:ffffea0004380e00 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 ffffea0004380f00 0000000500000005 ffff888100042f00 raw: ffff88810e039c00 000000008010000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 102, ts 4374421260, free_ts 0 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1937 [inline] new_slab+0xa0/0x4d0 mm/slub.c:2000 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033 __slab_alloc+0x49/0x90 mm/slub.c:3120 slab_alloc_node mm/slub.c:3211 [inline] slab_alloc mm/slub.c:3255 [inline] __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954 kmalloc_reserve net/core/skbuff.c:357 [inline] __alloc_skb+0x210/0x730 net/core/skbuff.c:428 alloc_skb include/linux/skbuff.h:1183 [inline] alloc_uevent_skb+0x85/0x240 lib/kobject_uevent.c:290 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast+0x335/0x5a0 lib/kobject_uevent.c:409 kobject_uevent_env+0x52b/0x700 lib/kobject_uevent.c:608 kobject_synth_uevent+0x457/0x940 lib/kobject_uevent.c:208 uevent_store+0x4b/0x70 drivers/base/bus.c:583 drv_attr_store+0x79/0xa0 drivers/base/bus.c:77 sysfs_kf_write+0x129/0x150 fs/sysfs/file.c:143 page_owner free stack trace missing Memory state around the buggy address: ffff88810e03ac00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810e03ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810e03ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810e03ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810e03ae00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================