================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline] BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline] BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline] BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline] BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline] BUG: KASAN: use-after-free in kref_get include/linux/kref.h:45 [inline] BUG: KASAN: use-after-free in svc_get include/linux/sunrpc/svc.h:108 [inline] BUG: KASAN: use-after-free in nfsd_shutdown_threads+0x89/0x1a0 fs/nfsd/nfssvc.c:641 Write of size 4 at addr ffff88802b80b050 by task syz-executor/4186 CPU: 1 PID: 4186 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x235/0x290 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline] __refcount_add include/linux/refcount.h:193 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] svc_get include/linux/sunrpc/svc.h:108 [inline] nfsd_shutdown_threads+0x89/0x1a0 fs/nfsd/nfssvc.c:641 nfsd_umount+0x3e/0xc0 fs/nfsd/nfsctl.c:1411 deactivate_locked_super+0x93/0xf0 fs/super.c:335 cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:184 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ff5e4d52397 Code: a2 c7 05 5c 43 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 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 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffc2d2c7f18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007ff5e4de74bb RCX: 00007ff5e4d52397 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc2d2c7fd0 RBP: 00007ffc2d2c7fd0 R08: 00007ffc2d2c8fd0 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc2d2c9060 R13: 00007ff5e4de74bb R14: 0000000000011b4e R15: 00007ffc2d2c90a0 Allocated by task 4288: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:607 [inline] kzalloc include/linux/slab.h:738 [inline] __svc_create+0x60/0x9d0 net/sunrpc/svc.c:485 svc_create_pooled+0x62f/0x810 net/sunrpc/svc.c:573 nfsd_create_serv+0x2f9/0x700 fs/nfsd/nfssvc.c:668 nfsd_svc+0x132/0x9e0 fs/nfsd/nfssvc.c:798 write_threads+0x2ea/0x350 fs/nfsd/nfsctl.c:426 nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114 vfs_write+0x304/0xd70 fs/read_write.c:592 ksys_write+0x153/0x260 fs/read_write.c:647 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 4288: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 kref_put include/linux/kref.h:65 [inline] svc_put include/linux/sunrpc/svc.h:123 [inline] nfsd_svc+0x7cf/0x9e0 fs/nfsd/nfssvc.c:821 write_threads+0x2ea/0x350 fs/nfsd/nfsctl.c:426 nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114 vfs_write+0x304/0xd70 fs/read_write.c:592 ksys_write+0x153/0x260 fs/read_write.c:647 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 ffff88802b80b000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 80 bytes inside of 512-byte region [ffff88802b80b000, ffff88802b80b200) The buggy address belongs to the page: page:ffffea0000ae0200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b808 head:ffffea0000ae0200 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001f11800 0000000600000006 ffff888016c41c80 raw: 0000000000000000 0000000000100010 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 1, ts 22874457495, free_ts 0 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] __kmalloc_node_track_caller+0x13d/0x3a0 mm/slub.c:4963 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x22c/0x750 net/core/skbuff.c:427 alloc_skb include/linux/skbuff.h:1162 [inline] alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:290 uevent_net_broadcast_tagged lib/kobject_uevent.c:351 [inline] kobject_uevent_net_broadcast+0x17e/0x530 lib/kobject_uevent.c:412 kobject_uevent_env+0x550/0x890 lib/kobject_uevent.c:608 device_add+0xac2/0x1050 drivers/base/core.c:3393 netdev_register_kobject+0x184/0x320 net/core/net-sysfs.c:2014 register_netdevice+0x10e8/0x1720 net/core/dev.c:10423 register_netdev+0x37/0x50 net/core/dev.c:10547 rose_proto_init+0x18d/0x780 net/rose/af_rose.c:1589 do_one_initcall+0x272/0x730 init/main.c:1276 page_owner free stack trace missing Memory state around the buggy address: ffff88802b80af00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802b80af80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802b80b000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b80b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b80b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================