panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 953 Starting stack trace... panic(ffffffff833952a6) at panic+0x1d0 sys/kern/subr_prf.c:229 __assert(ffffffff833d6cb0,ffffffff833e1459,3b9,ffffffff8340b082) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80003c437540,ffffffff8338f819) at refcnt_finalize+0x1db sys/kern/kern_synch.c:954 pppx_if_destroy(285b9a,ffff80003c437538) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose (285b9a,1,2000,ffff80003c49b4f0) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c497b70) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd806c15eb50,1,fffffd80097fb478,ffff80003c49b4f0) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd80745d0cd8,ffff80003c49b4f0) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd80745d0cd8,ffff80003c49b4f0) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd80745d0cd8,ffff80003c49b4f0) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd80745d0cd8,ffff80003c49b4f0) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80003c49b4f0) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80003c49b4f0,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80003c49b4f0,ffff80003c497ee0,ffff80003c497e30) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80003c497ee0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c497ee0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x79699801bc70, count: 242 End of stack trace. syncing disks...set $lines = 0 set $maxwidth = 0 show panic trace show registers show proc ps show all locks show malloc show all pools machine ddbcpu 0 trace machine ddbcpu 1 trace