svc: failed to register nfsdv3 RPC service (errno 111). svc: failed to register nfsaclv3 RPC service (errno 111). ================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [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_create_serv+0x104/0x6a4 fs/nfsd/nfssvc.c:661 Write of size 4 at addr ffff0000da94c050 by task syz.4.49/4519 CPU: 1 PID: 4519 Comm: syz.4.49 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x258/0x290 mm/kasan/generic.c:189 __kasan_check_write+0x2c/0x3c mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:102 [inline] atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [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_create_serv+0x104/0x6a4 fs/nfsd/nfssvc.c:661 nfsd_svc+0x168/0x948 fs/nfsd/nfssvc.c:796 write_threads+0x2b4/0x310 fs/nfsd/nfsctl.c:424 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114 vfs_write+0x2a8/0x7c8 fs/read_write.c:582 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Allocated by task 4519: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] __svc_create+0x80/0x89c net/sunrpc/svc.c:464 svc_create_pooled+0x648/0x7d8 net/sunrpc/svc.c:552 nfsd_create_serv+0x284/0x6a4 fs/nfsd/nfssvc.c:667 __write_ports_addfd fs/nfsd/nfsctl.c:716 [inline] __write_ports fs/nfsd/nfsctl.c:791 [inline] write_ports+0x3b8/0x9f0 fs/nfsd/nfsctl.c:847 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114 vfs_write+0x2a8/0x7c8 fs/read_write.c:582 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Freed by task 4519: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x21c mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 svc_destroy+0x144/0x184 net/sunrpc/svc.c:586 kref_put include/linux/kref.h:65 [inline] svc_put include/linux/sunrpc/svc.h:123 [inline] __write_ports_addfd fs/nfsd/nfsctl.c:728 [inline] __write_ports fs/nfsd/nfsctl.c:791 [inline] write_ports+0x7dc/0x9f0 fs/nfsd/nfsctl.c:847 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114 vfs_write+0x2a8/0x7c8 fs/read_write.c:582 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000da94c000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 80 bytes inside of 512-byte region [ffff0000da94c000, ffff0000da94c200) The buggy address belongs to the physical page: page:00000000d1387dde refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a94c head:00000000d1387dde order:2 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc00033ab200 dead000000000002 ffff0000c0002600 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000da94bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000da94bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000da94c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000da94c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000da94c100: 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: 4519 at lib/refcount.c:25 refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 4519 Comm: syz.4.49 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 lr : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 sp : ffff800021897780 x29: ffff800021897780 x28: dfff800000000000 x27: 1fffe0001e2e7858 x26: ffff0000f173c2c0 x25: ffff8000218977c0 x24: dfff800000000000 x23: ffff700004312ef8 x22: ffff80001c737000 x21: ffff0000d32f54c0 x20: ffff0000da94c050 x19: ffff800017d5d000 x18: 1fffe00033e7697e x17: ffff80001537d000 x16: ffff800008043b30 x15: 0000000040000000 x14: 0000000000000001 x13: 1fffe00033e79070 x12: 0000000000000000 x11: ff00800008048e14 x10: 0000000040000002 x9 : d3aea99bbf359500 x8 : d3aea99bbf359500 x7 : ffff800011cec160 x6 : ffff80000825ab50 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000 x2 : ffff800021897340 x1 : 0000000000000000 x0 : ffff80000825abe4 Call trace: refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 __refcount_add include/linux/refcount.h:-1 [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_create_serv+0x510/0x6a4 fs/nfsd/nfssvc.c:661 nfsd_svc+0x168/0x948 fs/nfsd/nfssvc.c:796 write_threads+0x2b4/0x310 fs/nfsd/nfsctl.c:424 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114 vfs_write+0x2a8/0x7c8 fs/read_write.c:582 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 3419 hardirqs last enabled at (3419): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline] hardirqs last enabled at (3419): [] finish_lock_switch+0xb0/0x1c8 kernel/sched/core.c:5005 hardirqs last disabled at (3418): [] __schedule+0x294/0x1a6c kernel/sched/core.c:6461 softirqs last enabled at (2960): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (2958): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000086000006 EC = 0x21: IABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x06: level 2 translation fault user pgtable: 4k pages, 48-bit VAs, pgdp=000000010fedb000 [0000000000000000] pgd=08000001035fb003, p4d=08000001035fb003, pud=080000011a2af003, pmd=0000000000000000 Internal error: Oops: 0000000086000006 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 4519 Comm: syz.4.49 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 pstate: 02400805 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=-c) pc : 0x0 lr : svc_register+0x100/0x214 net/sunrpc/svc.c:1085 sp : ffff8000218974e0 x29: ffff8000218974f0 x28: ffff0000f262ac94 x27: dfff800000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 1fffe0001e4c5592 x23: ffff0000f262ac80 x22: ffff0000d32f54c0 x21: 0000000000000011 x20: 0000000000000801 x19: 1fffe0001e4c5598 x18: 0000000000000060 x17: 0000000000001000 x16: ffff800008043b30 x15: ffff8000089b5c5c x14: 0000000000000001 x13: 1ffff00002b7cc9e x12: 0000000000080000 x11: ff00800010f0e314 x10: 0000000000000002 x9 : ffff80001c5fab10 x8 : 0000000000000000 x7 : ffff80000805a700 x6 : ffff80000805a910 x5 : 0000000000000801 x4 : 0000000000000011 x3 : 0000000000000002 x2 : 0000000000000000 x1 : ffff0000f262ac80 x0 : ffff0000d32f54c0 Call trace: 0x0 svc_setup_socket+0x118/0xe5c net/sunrpc/svcsock.c:1308 svc_create_socket+0x590/0x874 net/sunrpc/svcsock.c:1464 svc_udp_create+0x4c/0x64 net/sunrpc/svcsock.c:627 __svc_xpo_create net/sunrpc/svc_xprt.c:244 [inline] _svc_xprt_create+0x28c/0x76c net/sunrpc/svc_xprt.c:307 svc_xprt_create+0x5c/0xd8 net/sunrpc/svc_xprt.c:345 nfsd_init_socks fs/nfsd/nfssvc.c:295 [inline] nfsd_startup_net fs/nfsd/nfssvc.c:411 [inline] nfsd_svc+0x350/0x948 fs/nfsd/nfssvc.c:801 write_threads+0x2b4/0x310 fs/nfsd/nfsctl.c:424 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114 vfs_write+0x2a8/0x7c8 fs/read_write.c:582 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Code: bad PC value ---[ end trace 0000000000000000 ]---