panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 955
Starting stack trace...
panic(ffffffff833b113f) at panic+0x1d0 sys/kern/subr_prf.c:229
__assert(ffffffff833ede98,ffffffff833fdb47,3bb,ffffffff83428070) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff8000343dddb8,ffffffff833a7e4c) at refcnt_finalize+0x1db sys/kern/kern_synch.c:956
pppx_if_destroy(205b9a,ffff8000343dddb0) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80003c402ff0) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a33aa00) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8063854478,2,fffffd80097fd2d8,ffff80003c402ff0) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd806c85d8f8,ffff80003c402ff0) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd806c85d8f8,ffff80003c402ff0) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd806c85d8f8,ffff80003c402ff0) at fdrop+0x121 sys/kern/kern_descrip.c:1280
closef(fffffd806c85d8f8,ffff80003c402ff0) at closef+0x192 sys/kern/kern_descrip.c:1264
syscall(ffff80002a33ac60) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a33ac60) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x448628f6730, count: 245
End of stack trace.