================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: slab-use-after-free in test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] BUG: KASAN: slab-use-after-free in l2tp_session_delete+0x23/0x830 net/l2tp/l2tp_core.c:1639 Write of size 8 at addr ffff888046a5b808 by task kworker/u8:6/1035 CPU: 0 PID: 1035 Comm: kworker/u8:6 Not tainted 6.10.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: l2tp l2tp_tunnel_del_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x280 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] l2tp_session_delete+0x23/0x830 net/l2tp/l2tp_core.c:1639 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1302 [inline] l2tp_tunnel_del_work+0xf3/0x3a0 net/l2tp/l2tp_core.c:1334 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0x8cf/0x1320 kernel/workqueue.c:3312 worker_thread+0x869/0xca0 kernel/workqueue.c:3393 kthread+0x268/0x2c0 kernel/kthread.c:389 ret_from_fork+0x32/0x60 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 3142: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:4122 [inline] __kmalloc_noprof+0x1d5/0x440 mm/slub.c:4135 kmalloc_noprof include/linux/slab.h:664 [inline] kzalloc_noprof include/linux/slab.h:778 [inline] l2tp_session_create+0x34/0xb90 net/l2tp/l2tp_core.c:1675 pppol2tp_connect+0xb4e/0x1650 net/l2tp/l2tp_ppp.c:782 __sys_connect_file net/socket.c:2049 [inline] __sys_connect+0x318/0x390 net/socket.c:2066 __do_sys_connect net/socket.c:2076 [inline] __se_sys_connect net/socket.c:2073 [inline] __x64_sys_connect+0x75/0x90 net/socket.c:2073 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x8d/0x170 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 2728: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2196 [inline] slab_free mm/slub.c:4437 [inline] kfree+0x12f/0x310 mm/slub.c:4558 __sk_destruct+0x4b/0x550 net/core/sock.c:2191 rcu_do_batch kernel/rcu/tree.c:2535 [inline] rcu_core+0xc3c/0x1470 kernel/rcu/tree.c:2809 handle_softirqs+0x1b7/0x570 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0x45/0xe0 kernel/softirq.c:637 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x92/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541 __call_rcu_common kernel/rcu/tree.c:3072 [inline] call_rcu+0x159/0x8e0 kernel/rcu/tree.c:3176 pppol2tp_release+0x1c5/0x250 net/l2tp/l2tp_ppp.c:457 __sock_release net/socket.c:659 [inline] sock_close+0xb4/0x220 net/socket.c:1421 __fput+0x337/0x700 fs/file_table.c:422 task_work_run+0x20f/0x290 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xb5/0x1c0 kernel/entry/common.c:218 do_syscall_64+0x9a/0x170 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888046a5b800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 8 bytes inside of freed 1024-byte region [ffff888046a5b800, ffff888046a5bc00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x46a58 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffefff(slab) raw: 00fff00000000040 ffff888009841dc0 ffffea00017d2600 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000 head: 00fff00000000040 ffff888009841dc0 ffffea00017d2600 dead000000000002 head: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000 head: 00fff00000000003 ffffea00011a9601 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 1881, tgid 1881 (kworker/u8:4), ts 28236816161, free_ts 28167340684 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x10f/0x130 mm/page_alloc.c:1468 prep_new_page mm/page_alloc.c:1476 [inline] get_page_from_freelist+0x2c3f/0x2cf0 mm/page_alloc.c:3420 __alloc_pages_noprof+0x256/0x670 mm/page_alloc.c:4678 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x5f/0x120 mm/slub.c:2265 allocate_slab+0x5d/0x290 mm/slub.c:2428 new_slab mm/slub.c:2481 [inline] ___slab_alloc+0xa7f/0x11d0 mm/slub.c:3667 __slab_alloc mm/slub.c:3757 [inline] __slab_alloc_node mm/slub.c:3810 [inline] slab_alloc_node mm/slub.c:3989 [inline] __do_kmalloc_node mm/slub.c:4121 [inline] __kmalloc_noprof+0x25a/0x440 mm/slub.c:4135 kmalloc_noprof include/linux/slab.h:664 [inline] load_elf_phdrs+0xe1/0x1f0 fs/binfmt_elf.c:526 load_elf_binary+0x81c/0x2390 fs/binfmt_elf.c:955 search_binary_handler fs/exec.c:1797 [inline] exec_binprm fs/exec.c:1839 [inline] bprm_execve+0x891/0x12f0 fs/exec.c:1891 kernel_execve+0x532/0x610 fs/exec.c:2058 call_usermodehelper_exec_async+0x204/0x320 kernel/umh.c:110 ret_from_fork+0x32/0x60 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 page last free pid 1872 tgid 1872 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1088 [inline] free_unref_page+0xb6f/0xca0 mm/page_alloc.c:2583 discard_slab mm/slub.c:2527 [inline] __put_partials+0x18e/0x1d0 mm/slub.c:2995 put_cpu_partial+0x151/0x1b0 mm/slub.c:3070 __slab_free+0x2b8/0x3a0 mm/slub.c:4307 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3941 [inline] slab_alloc_node mm/slub.c:4001 [inline] kmem_cache_alloc_noprof+0x12b/0x350 mm/slub.c:4008 getname_flags+0xa1/0x440 fs/namei.c:139 user_path_at_empty+0x1f/0x50 fs/namei.c:2928 user_path_at include/linux/namei.h:58 [inline] do_faccessat+0x49f/0x930 fs/open.c:490 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x8d/0x170 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888046a5b700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888046a5b780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888046a5b800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888046a5b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888046a5b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================