================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x31/0x190 lib/list_debug.c:49 Read of size 8 at addr ffff888034038d38 by task syz.0.17/6408 CPU: 0 UID: 0 PID: 6408 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __list_del_entry_valid_or_report+0x31/0x190 lib/list_debug.c:49 __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del_init include/linux/list.h:295 [inline] fuse_read_interrupt+0xdb/0x410 fs/fuse/dev.c:1267 fuse_dev_do_read+0xa62/0x1280 fs/fuse/dev.c:1464 fuse_dev_read+0x16a/0x200 fs/fuse/dev.c:1586 io_iter_do_read io_uring/rw.c:835 [inline] __io_read+0x724/0x14f0 io_uring/rw.c:952 io_read+0x4a/0x1c0 io_uring/rw.c:1031 __io_issue_sqe+0x180/0x4b0 io_uring/io_uring.c:1387 io_issue_sqe+0x165/0xf60 io_uring/io_uring.c:1410 io_queue_sqe io_uring/io_uring.c:1636 [inline] io_req_task_submit+0xe6/0x180 io_uring/io_uring.c:1050 io_poll_task_func+0x99d/0xc30 io_uring/poll.c:-1 io_handle_tw_list+0x258/0x540 io_uring/tw.c:72 tctx_task_work_run+0x55/0x300 io_uring/tw.c:132 tctx_task_work+0x3f/0x90 io_uring/tw.c:150 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11eb/0x1330 kernel/signal.c:2809 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fed8a39c819 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:00007fed8b2d3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: fffffffffffffffc RBX: 00007fed8a616090 RCX: 00007fed8a39c819 RDX: 0000000000040000 RSI: 0000200000000140 RDI: ffffffffffffff9c RBP: 00007fed8a432c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000020 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fed8a616128 R14: 00007fed8a616090 R15: 00007fff48598688 Allocated by task 6408: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 fuse_request_alloc fs/fuse/dev.c:142 [inline] fuse_get_req+0x7da/0x10d0 fs/fuse/dev.c:225 __fuse_simple_request+0x2cf/0x1db0 fs/fuse/dev.c:688 fuse_simple_request fs/fuse/fuse_i.h:1262 [inline] fuse_lookup_name+0x35e/0x8b0 fs/fuse/dir.c:578 fuse_lookup+0x213/0x4e0 fs/fuse/dir.c:625 fuse_atomic_open+0x196/0x430 fs/fuse/dir.c:944 atomic_open+0x14f/0x370 fs/namei.c:4364 lookup_open fs/namei.c:4477 [inline] open_last_lookups fs/namei.c:4611 [inline] path_openat+0x10e9/0x3860 fs/namei.c:4855 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6408: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6246 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6373 __fuse_simple_request+0x175a/0x1db0 fs/fuse/dev.c:705 fuse_simple_request fs/fuse/fuse_i.h:1262 [inline] fuse_lookup_name+0x35e/0x8b0 fs/fuse/dir.c:578 fuse_lookup+0x213/0x4e0 fs/fuse/dir.c:625 fuse_atomic_open+0x196/0x430 fs/fuse/dir.c:944 atomic_open+0x14f/0x370 fs/namei.c:4364 lookup_open fs/namei.c:4477 [inline] open_last_lookups fs/namei.c:4611 [inline] path_openat+0x10e9/0x3860 fs/namei.c:4855 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888034038d20 which belongs to the cache fuse_request of size 216 The buggy address is located 24 bytes inside of freed 216-byte region [ffff888034038d20, ffff888034038df8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34038 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff888140ea9c80 dead000000000122 0000000000000000 raw: 0000000000000000 00000008000e000e 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6404, tgid 6402 (syz.0.17), ts 146863634674, free_ts 146855454643 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7251 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4905 fuse_request_alloc fs/fuse/dev.c:142 [inline] fuse_simple_background+0x9f/0x1040 fs/fuse/dev.c:767 fuse_send_init+0x3ec/0x740 fs/fuse/inode.c:1590 vfs_get_super fs/super.c:1327 [inline] get_tree_nodev+0xbb/0x150 fs/super.c:1346 fuse_get_tree+0x295/0x3b0 fs/fuse/inode.c:2055 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3834 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4360 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 9 tgid 9 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __tlb_remove_table_free mm/mmu_gather.c:228 [inline] tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x1aa/0x7d0 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_cr net/ipv6/mcast.c:2148 [inline] mld_ifc_work+0x6e6/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888034038c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888034038c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888034038d00: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb ^ ffff888034038d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff888034038e00: fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb ==================================================================