================================================================== BUG: KASAN: use-after-free in atomic_fetch_add include/asm-generic/atomic-instrumented.h:111 [inline] BUG: KASAN: use-after-free in refcount_add include/linux/refcount.h:188 [inline] BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:228 [inline] BUG: KASAN: use-after-free in get_task_struct include/linux/sched/task.h:112 [inline] BUG: KASAN: use-after-free in kthread_stop+0x37/0x4a0 kernel/kthread.c:612 Write of size 4 at addr ffff8881e3f68fe0 by task syz-executor/6689 CPU: 1 PID: 6689 Comm: syz-executor Tainted: G W 5.4.289-syzkaller-00030-gcb850525fc3e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 check_memory_region_inline mm/kasan/generic.c:141 [inline] check_memory_region+0x272/0x280 mm/kasan/generic.c:191 atomic_fetch_add include/asm-generic/atomic-instrumented.h:111 [inline] refcount_add include/linux/refcount.h:188 [inline] refcount_inc include/linux/refcount.h:228 [inline] get_task_struct include/linux/sched/task.h:112 [inline] kthread_stop+0x37/0x4a0 kernel/kthread.c:612 ext4_put_super+0x790/0xbb0 fs/ext4/super.c:1055 generic_shutdown_super+0x120/0x300 fs/super.c:464 kill_block_super+0x7a/0xe0 fs/super.c:1455 deactivate_locked_super+0xa8/0x110 fs/super.c:335 deactivate_super+0x1e2/0x2a0 fs/super.c:366 cleanup_mnt+0x44e/0x500 fs/namespace.c:1102 task_work_run+0x140/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7febc4bcc117 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffd7aeb9ee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007febc4bcc117 RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffd7aebb090 RBP: 00007febc4c4c08c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffd7aebb090 R13: 00007febc4c4c08c R14: 000055558d4564a8 R15: 00007ffd7aebc160 Allocated by task 2: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct+0x4f/0x600 kernel/fork.c:882 copy_process+0x56d/0x3230 kernel/fork.c:1889 _do_fork+0x197/0x900 kernel/fork.c:2399 kernel_thread+0x16a/0x1d0 kernel/fork.c:2489 create_kthread kernel/kthread.c:311 [inline] kthreadd+0x3b1/0x4f0 kernel/kthread.c:654 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Freed by task 17: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 The buggy address belongs to the object at ffff8881e3f68fc0 which belongs to the cache task_struct of size 3904 The buggy address is located 32 bytes inside of 3904-byte region [ffff8881e3f68fc0, ffff8881e3f69f00) The buggy address belongs to the page: page:ffffea00078fda00 refcount:1 mapcount:0 mapping:ffff8881f5cf0780 index:0xffff8881e3f6af40 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 ffffea00078d5e00 0000000200000002 ffff8881f5cf0780 raw: ffff8881e3f6af40 0000000080080005 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] kmem_cache_alloc+0x109/0x250 mm/slub.c:2842 kmem_cache_alloc_node include/linux/slab.h:427 [inline] alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct+0x4f/0x600 kernel/fork.c:882 copy_process+0x56d/0x3230 kernel/fork.c:1889 _do_fork+0x197/0x900 kernel/fork.c:2399 __do_sys_clone kernel/fork.c:2557 [inline] __se_sys_clone kernel/fork.c:2538 [inline] __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] __free_pages_ok+0x847/0x950 mm/page_alloc.c:1438 put_page include/linux/mm.h:1153 [inline] __skb_frag_unref include/linux/skbuff.h:3062 [inline] skb_release_data+0x210/0x640 net/core/skbuff.c:615 skb_release_all net/core/skbuff.c:675 [inline] __kfree_skb+0x4c/0x60 net/core/skbuff.c:689 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3232 [inline] tcp_ack+0x20cb/0x6080 net/ipv4/tcp_input.c:3783 tcp_rcv_established+0xd16/0x1a80 net/ipv4/tcp_input.c:5742 tcp_v4_do_rcv+0x3a9/0x770 net/ipv4/tcp_ipv4.c:1598 tcp_v4_rcv+0x219a/0x26f0 net/ipv4/tcp_ipv4.c:1990 ip_protocol_deliver_rcu+0x2e0/0x630 net/ipv4/ip_input.c:204 ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] ip_local_deliver+0x2c6/0x5a0 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:444 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:541 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:579 [inline] ip_sublist_rcv+0xc02/0xc80 net/ipv4/ip_input.c:587 ip_list_rcv+0x477/0x4c0 net/ipv4/ip_input.c:621 __netif_receive_skb_list_ptype net/core/dev.c:5034 [inline] __netif_receive_skb_list_core+0x6dd/0x8f0 net/core/dev.c:5082 __netif_receive_skb_list net/core/dev.c:5134 [inline] netif_receive_skb_list_internal+0x944/0xc90 net/core/dev.c:5229 gro_normal_list net/core/dev.c:5340 [inline] napi_complete_done+0x20a/0x580 net/core/dev.c:6071 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline] virtnet_poll+0xb6b/0x1250 drivers/net/virtio_net.c:1516 napi_poll net/core/dev.c:6386 [inline] net_rx_action+0x53f/0x1160 net/core/dev.c:6454 Memory state around the buggy address: ffff8881e3f68e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881e3f68f00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8881e3f68f80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8881e3f69000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881e3f69080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 6689 at lib/refcount.c:25 refcount_warn_saturate+0x132/0x1a0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 6689 Comm: syz-executor Tainted: G B W 5.4.289-syzkaller-00030-gcb850525fc3e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:refcount_warn_saturate+0x132/0x1a0 lib/refcount.c:25 Code: 04 01 48 c7 c7 60 1d fa 84 e8 ea 8d 0d ff 0f 0b eb a9 e8 71 eb 36 ff c6 05 56 0e 1d 04 01 48 c7 c7 e0 1d fa 84 e8 ce 8d 0d ff <0f> 0b eb 8d e8 55 eb 36 ff c6 05 3b 0e 1d 04 01 48 c7 c7 40 1e fa RSP: 0018:ffff8881d73bfc30 EFLAGS: 00010246 RAX: f686d40737e22f00 RBX: 0000000000000002 RCX: ffff8881e4a09f80 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffffff814d6d92 R09: ffffed103edea9b8 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: ffff8881e3f68fc0 R14: dffffc0000000000 R15: ffff8881e3f68fe0 FS: 000055558d456500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056523a60d0f8 CR3: 00000001f27d0000 CR4: 00000000003406a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: refcount_add include/linux/refcount.h:192 [inline] refcount_inc include/linux/refcount.h:228 [inline] get_task_struct include/linux/sched/task.h:112 [inline] kthread_stop+0x1a5/0x4a0 kernel/kthread.c:612 ext4_put_super+0x790/0xbb0 fs/ext4/super.c:1055 generic_shutdown_super+0x120/0x300 fs/super.c:464 kill_block_super+0x7a/0xe0 fs/super.c:1455 deactivate_locked_super+0xa8/0x110 fs/super.c:335 deactivate_super+0x1e2/0x2a0 fs/super.c:366 cleanup_mnt+0x44e/0x500 fs/namespace.c:1102 task_work_run+0x140/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7febc4bcc117 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffd7aeb9ee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007febc4bcc117 RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffd7aebb090 RBP: 00007febc4c4c08c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffd7aebb090 R13: 00007febc4c4c08c R14: 000055558d4564a8 R15: 00007ffd7aebc160 ---[ end trace d17f69b840735216 ]---