================================================================== BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:72 [inline] BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:147 [inline] BUG: KASAN: use-after-free in tcp_metrics_flush_all+0xd3/0x210 net/ipv4/tcp_metrics.c:909 Read of size 4 at addr ffff8881230ca38c by task kworker/u4:24/2814 CPU: 0 PID: 2814 Comm: kworker/u4:24 Tainted: G W 6.1.141-syzkaller-00038-ge2deb0b42a3a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: netns cleanup_net Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106 print_address_description+0x71/0x210 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:427 kasan_report+0x122/0x150 mm/kasan/report.c:531 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x280/0x290 mm/kasan/generic.c:189 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:72 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] refcount_read include/linux/refcount.h:147 [inline] tcp_metrics_flush_all+0xd3/0x210 net/ipv4/tcp_metrics.c:909 tcp_net_metrics_exit_batch+0x10/0x20 net/ipv4/tcp_metrics.c:1037 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x62d/0xb00 net/core/net_namespace.c:604 process_one_work+0x71f/0xc40 kernel/workqueue.c:2299 worker_thread+0xa29/0x11f0 kernel/workqueue.c:2446 kthread+0x281/0x320 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 285: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:333 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768 slab_alloc_node mm/slub.c:3421 [inline] slab_alloc mm/slub.c:3431 [inline] __kmem_cache_alloc_lru mm/slub.c:3438 [inline] kmem_cache_alloc+0x16e/0x330 mm/slub.c:3447 kmem_cache_zalloc include/linux/slab.h:689 [inline] net_alloc net/core/net_namespace.c:413 [inline] copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:468 create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226 ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3388 __do_sys_unshare kernel/fork.c:3459 [inline] __se_sys_unshare kernel/fork.c:3457 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3457 x64_sys_call+0x767/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 312: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1745 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1771 slab_free mm/slub.c:3686 [inline] kmem_cache_free+0x12d/0x300 mm/slub.c:3711 net_free net/core/net_namespace.c:442 [inline] cleanup_net+0xa58/0xb00 net/core/net_namespace.c:625 process_one_work+0x71f/0xc40 kernel/workqueue.c:2299 worker_thread+0xa29/0x11f0 kernel/workqueue.c:2446 kthread+0x281/0x320 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 insert_work+0x51/0x300 kernel/workqueue.c:1368 __queue_work+0x9b1/0xd30 kernel/workqueue.c:1527 delayed_work_timer_fn+0x61/0x80 kernel/workqueue.c:1653 call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1510 expire_timers kernel/time/timer.c:1550 [inline] __run_timers+0x667/0x9a0 kernel/time/timer.c:1826 run_timer_softirq+0xb8/0xf0 kernel/time/timer.c:1841 handle_softirqs+0x1d7/0x600 kernel/softirq.c:642 __do_softirq kernel/softirq.c:680 [inline] invoke_softirq kernel/softirq.c:497 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729 irq_exit_rcu+0x9/0x10 kernel/softirq.c:741 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691 Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 insert_work+0x51/0x300 kernel/workqueue.c:1368 __queue_work+0x9b1/0xd30 kernel/workqueue.c:1527 delayed_work_timer_fn+0x61/0x80 kernel/workqueue.c:1653 call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1510 expire_timers kernel/time/timer.c:1550 [inline] __run_timers+0x667/0x9a0 kernel/time/timer.c:1826 run_timer_softirq+0xb8/0xf0 kernel/time/timer.c:1841 handle_softirqs+0x1d7/0x600 kernel/softirq.c:642 __do_softirq kernel/softirq.c:680 [inline] invoke_softirq kernel/softirq.c:497 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729 irq_exit_rcu+0x9/0x10 kernel/softirq.c:741 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691 The buggy address belongs to the object at ffff8881230ca300 which belongs to the cache net_namespace of size 4224 The buggy address is located 140 bytes inside of 4224-byte region [ffff8881230ca300, ffff8881230cb380) The buggy address belongs to the physical page: page:ffffea00048c3200 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8881230c8000 pfn:0x1230c8 head:ffffea00048c3200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 ffffea00045cc800 dead000000000002 ffff8881002ac180 raw: ffff8881230c8000 0000000080070006 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 285, tgid 285 (syz-executor), ts 27165878114, free_ts 25513017723 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2637 prep_new_page+0x1c/0x110 mm/page_alloc.c:2644 get_page_from_freelist+0x2c7b/0x2cf0 mm/page_alloc.c:4539 __alloc_pages+0x19e/0x3a0 mm/page_alloc.c:5850 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1 allocate_slab mm/slub.c:1962 [inline] new_slab+0x98/0x3d0 mm/slub.c:2015 ___slab_alloc+0x6f6/0xb50 mm/slub.c:3203 __slab_alloc+0x5e/0xa0 mm/slub.c:3302 slab_alloc_node mm/slub.c:3387 [inline] slab_alloc mm/slub.c:3431 [inline] __kmem_cache_alloc_lru mm/slub.c:3438 [inline] kmem_cache_alloc+0x1b0/0x330 mm/slub.c:3447 kmem_cache_zalloc include/linux/slab.h:689 [inline] net_alloc net/core/net_namespace.c:413 [inline] copy_net_ns+0x145/0x5c0 net/core/net_namespace.c:468 create_new_namespaces+0x3a2/0x660 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:226 ksys_unshare+0x4ac/0x7b0 kernel/fork.c:3388 __do_sys_unshare kernel/fork.c:3459 [inline] __se_sys_unshare kernel/fork.c:3457 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3457 x64_sys_call+0x767/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:273 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1545 [inline] free_pcp_prepare mm/page_alloc.c:1619 [inline] free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3581 free_unref_page+0x8f/0x530 mm/page_alloc.c:3677 free_the_page mm/page_alloc.c:830 [inline] free_compound_page+0x99/0xd0 mm/page_alloc.c:853 destroy_large_folio+0x68/0xa0 mm/page_alloc.c:890 __folio_put_large mm/swap.c:110 [inline] __folio_put+0xd1/0xe0 mm/swap.c:118 folio_put include/linux/mm.h:1431 [inline] put_page include/linux/mm.h:1483 [inline] __skb_frag_unref include/linux/skbuff.h:3455 [inline] skb_frag_unref include/linux/skbuff.h:3470 [inline] __pskb_trim_head+0x45b/0x7b0 net/ipv4/tcp_output.c:1650 tcp_trim_head+0x126/0x680 net/ipv4/tcp_output.c:1677 tcp_tso_acked net/ipv4/tcp_input.c:3278 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3344 [inline] tcp_ack+0x1864/0x5cd0 net/ipv4/tcp_input.c:3967 tcp_rcv_established+0x72d/0x19f0 net/ipv4/tcp_input.c:6099 tcp_v4_do_rcv+0x446/0xa10 net/ipv4/tcp_ipv4.c:1683 sk_backlog_rcv include/net/sock.h:1131 [inline] __release_sock+0x154/0x380 net/core/sock.c:2945 release_sock+0x60/0x1c0 net/core/sock.c:3519 tcp_sendmsg+0x39/0x50 net/ipv4/tcp.c:1489 inet_sendmsg+0xb6/0xd0 net/ipv4/af_inet.c:841 sock_sendmsg_nosec net/socket.c:716 [inline] __sock_sendmsg net/socket.c:728 [inline] sock_write_iter+0x2ca/0x3b0 net/socket.c:1133 call_write_iter include/linux/fs.h:2282 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x5db/0xca0 fs/read_write.c:584 Memory state around the buggy address: ffff8881230ca280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881230ca300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881230ca380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881230ca400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881230ca480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================