panic: kernel diagnostic assertion "rn != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/net/pipex.c", line 459 Starting stack trace... panic(ffffffff833afb93) at panic+0x1d0 sys/kern/subr_prf.c:229 __assert(ffffffff833edad3,ffffffff83404aaa,1cb,ffffffff833a2685) at __assert+0x29 sys/kern/subr_prf.c:-1 pipex_unlink_session_locked(ffff80003c447338) at pipex_unlink_session_locked+0x409 pipex_destroy_all_sessions(ffff80000148d800) at pipex_destroy_all_sessions+0xd9 pipex_rele_session sys/net/pipex.c:-1 [inline] pipex_destroy_all_sessions(ffff80000148d800) at pipex_destroy_all_sessions+0xd9 sys/net/pipex.c:151 pppacclose(637e,81,2000,ffff8000fffebca8) at pppacclose+0x16f sys/net/if_pppx.c:1335 spec_close(ffff80003c427410) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805d5f5378,81,fffffd80097fd548,ffff8000fffebca8) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd807a873488,ffff8000fffebca8) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd807a873488,ffff8000fffebca8) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd807a873488,ffff8000fffebca8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd807a873488,ffff8000fffebca8) at closef+0x192 sys/kern/kern_descrip.c:1264 syscall(ffff80003c427670) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c427670) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xe9106405c40, count: 245 End of stack trace. syncing disks...