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How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

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(gdb) bt full
#0  I_lg (xl=4398007891115, x=0xffff740db5c8) at beam/big.c:1636
        sz = 4398007891114
        d = <optimized out>
#1  big_integer_estimate (x=x@entry=281472628798914, base=base@entry=10) at beam/big.c:1915
        xp = 0xffff740db5c0
        lg = <optimized out>
        lgBase = <optimized out>
#2  0x0000aaaae0ec0fac in print_term (dcount=0xffff6e366658, obj=<optimized out>, arg=0xffff5c214d80, fn=0xaaaae104e704 <erts_write_fp>) at beam/erl_printf_term.c:481
        def_buf = "\331\330\v᪪\000\000\377\377\377\377\000\000\000\000\000o\217#\020\177{\034pg6n\377\377\000\000\274\276\004᪪\000\000\240i6n\377\377\000\000\330\377\377\377\000\000\000\000\004\347\004᪪\000"

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 objdump -p  ./artifacts/bin/linux/arm64_Debug_openssl/msquictest

./artifacts/bin/linux/arm64_Debug_openssl/msquictest:     file format elf64-littleaarch64

Program Header:
    PHDR off    0x0000000000000040 vaddr 0x0000000000000040 paddr 0x0000000000000040 align 2**3
         filesz 0x00000000000001f8 memsz 0x00000000000001f8 flags r--
  INTERP off    0x0000000000000238 vaddr 0x0000000000000238 paddr 0x0000000000000238 align 2**0
         filesz 0x000000000000001b memsz 0x000000000000001b flags r--
    LOAD off    0x0000000000000000 vaddr 0x0000000000000000 paddr 0x0000000000000000 align 2**16

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Branch: master attempts max: 8 : https://api.github.com/repos/emqx/emqx/actions/runs/5136332850 Generated at 2023-06-01 16:09:31.526180

suite	case	total failed times
emqx_bridge_kafka_impl_consumer_SUITE	sasl_plain.sasl_auth_kerberos.t_start_and_consume_ok	6
emqx_bridge_kafka_impl_consumer_SUITE	sasl_ssl.sasl_auth_kerberos.t_start_and_consume_ok	5
emqx_bridge_cassandra_SUITE	tls.async.with_batch.t_write_failure	5
emqx_bridge_pulsar_impl_producer_SUITE	plain.t_send_when_down	5
emqx_ee_bridge_redis_SUITE	rest.t_check_replay	5

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dbg:tracer(process, {fun dbg:dhandler/2,group_leader()}).
dbg:p(all, c).
dbg:tpl(mnesia_loader, init_receiver, cx).
mnesia_lib:set(copy_from_node, '[email protected]').
mnesia:del_table_copy(emqx_trie, '[email protected]').
mnesia:add_table_copy(emqx_trie, '[email protected]', ram_copies).
mnesia:wait_for_tables([emqx_trie], 30000).

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#!/usr/bin/env escript
%% find cache leaks from a recon fragmentation dump:
%% input file should look like as following:
%% [{{ets_alloc,1},
%%   [{sbcs_usage,1.0},
%%    {mbcs_usage,0.3708287885109216},
%%    {sbcs_block_size,0},
%%    {sbcs_carriers_size,0},
%%    {mbcs_block_size,2040364216},
%%    {mbcs_carriers_size,5502173184}]},

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#!/usr/bin/env escript
%% find unabandoned carriers and their size, aka cache leaks.
%% note, file should be consultable erlang term file which means it has a '.' at the end of input file.
main([File]) ->
    case file:consult(File) of
        {error, _} = E->
            io:format("bad input ~p: ~p", [File, E]);
        {ok, [Raw]} ->
            Caches = [{Name, Number, Size}
                      || {Name, Prop}<-Raw, {mbcs_pool, Pool}<- Prop, {carriers_size, Size} <- Pool, {carriers, Number} <- Pool],

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#!/usr/bin/env escript
%% -*- erlang -*-
main(["usage"]) ->
    io:format("./schema_fix.escript [--dry-run] schema.DAT [add | replace] '[email protected]' ~n",
              []);
main(["--dry-run", SchemaFile, Op, NodeStr]) ->
    run(true, SchemaFile, Op, NodeStr);
main([SchemaFile, Op, NodeStr]) ->
    run(false, SchemaFile, Op, NodeStr);
main(_) ->

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--- a/src/wl/sys/wl_cfg80211_hybrid.c	2017-05-19 20:39:02.140010833 +0200
+++ b/src/wl/sys/wl_cfg80211_hybrid.c	2017-05-19 20:40:19.216011777 +0200
@@ -2153,8 +2153,12 @@
 	WL_DBG(("\n"));

 	if (status == WLC_E_STATUS_SUCCESS) {
-		err = wl_bss_roaming_done(wl, ndev, e, data);
+		if (!wl_bss_roaming_done(wl, ndev, e, data)) {
 		wl->profile->active = true;
+		} else {