From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48034) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cReei-0007IH-8S for qemu-devel@nongnu.org; Thu, 12 Jan 2017 07:39:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cReed-0002qA-7Z for qemu-devel@nongnu.org; Thu, 12 Jan 2017 07:39:00 -0500 From: Thomas Huth Date: Thu, 12 Jan 2017 13:38:52 +0100 Message-Id: <1484224732-1345-1-git-send-email-thuth@redhat.com> Subject: [Qemu-devel] [PATCH v3] monitor: Fix crashes when using HMP commands without CPU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-trivial@nongnu.org Cc: qemu-devel@nongnu.org, "Dr. David Alan Gilbert" When running certain HMP commands ("info registers", "info cpustats", "nmi", "memsave" or dumping virtual memory) with the "none" machine, QEMU crashes with a segmentation fault. This happens because the "none" machine does not have any CPUs by default, but these HMP commands did not check for a valid CPU pointer yet. Add such checks now, so we get an error message about the missing CPU instead. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Thomas Huth --- v3: - Use UNASSIGNED_CPU_INDEX instead of hard-coded -1 v2: - Added more checks to cover "nmi" and "memsave", too hmp.c | 8 +++++++- monitor.c | 37 +++++++++++++++++++++++++++++++------ 2 files changed, 38 insertions(+), 7 deletions(-) diff --git a/hmp.c b/hmp.c index b869617..b1c503a 100644 --- a/hmp.c +++ b/hmp.c @@ -1013,8 +1013,14 @@ void hmp_memsave(Monitor *mon, const QDict *qdict) const char *filename = qdict_get_str(qdict, "filename"); uint64_t addr = qdict_get_int(qdict, "val"); Error *err = NULL; + int cpu_index = monitor_get_cpu_index(); - qmp_memsave(addr, size, filename, true, monitor_get_cpu_index(), &err); + if (cpu_index < 0) { + monitor_printf(mon, "No CPU available\n"); + return; + } + + qmp_memsave(addr, size, filename, true, cpu_index, &err); hmp_handle_error(mon, &err); } diff --git a/monitor.c b/monitor.c index 0841d43..17121ff 100644 --- a/monitor.c +++ b/monitor.c @@ -1025,6 +1025,9 @@ int monitor_set_cpu(int cpu_index) CPUState *mon_get_cpu(void) { if (!cur_mon->mon_cpu) { + if (!first_cpu) { + return NULL; + } monitor_set_cpu(first_cpu->cpu_index); } cpu_synchronize_state(cur_mon->mon_cpu); @@ -1033,17 +1036,27 @@ CPUState *mon_get_cpu(void) CPUArchState *mon_get_cpu_env(void) { - return mon_get_cpu()->env_ptr; + CPUState *cs = mon_get_cpu(); + + return cs ? cs->env_ptr : NULL; } int monitor_get_cpu_index(void) { - return mon_get_cpu()->cpu_index; + CPUState *cs = mon_get_cpu(); + + return cs ? cs->cpu_index : UNASSIGNED_CPU_INDEX; } static void hmp_info_registers(Monitor *mon, const QDict *qdict) { - cpu_dump_state(mon_get_cpu(), (FILE *)mon, monitor_fprintf, CPU_DUMP_FPU); + CPUState *cs = mon_get_cpu(); + + if (!cs) { + monitor_printf(mon, "No CPU available\n"); + return; + } + cpu_dump_state(cs, (FILE *)mon, monitor_fprintf, CPU_DUMP_FPU); } static void hmp_info_jit(Monitor *mon, const QDict *qdict) @@ -1076,7 +1089,13 @@ static void hmp_info_history(Monitor *mon, const QDict *qdict) static void hmp_info_cpustats(Monitor *mon, const QDict *qdict) { - cpu_dump_statistics(mon_get_cpu(), (FILE *)mon, &monitor_fprintf, 0); + CPUState *cs = mon_get_cpu(); + + if (!cs) { + monitor_printf(mon, "No CPU available\n"); + return; + } + cpu_dump_statistics(cs, (FILE *)mon, &monitor_fprintf, 0); } static void hmp_info_trace_events(Monitor *mon, const QDict *qdict) @@ -1235,6 +1254,12 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize, int l, line_size, i, max_digits, len; uint8_t buf[16]; uint64_t v; + CPUState *cs = mon_get_cpu(); + + if (!cs && (format == 'i' || !is_physical)) { + monitor_printf(mon, "Can not dump without CPU\n"); + return; + } if (format == 'i') { int flags = 0; @@ -1264,7 +1289,7 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize, flags = msr_le << 16; flags |= env->bfd_mach; #endif - monitor_disas(mon, mon_get_cpu(), addr, count, is_physical, flags); + monitor_disas(mon, cs, addr, count, is_physical, flags); return; } @@ -1303,7 +1328,7 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize, if (is_physical) { cpu_physical_memory_read(addr, buf, l); } else { - if (cpu_memory_rw_debug(mon_get_cpu(), addr, buf, l, 0) < 0) { + if (cpu_memory_rw_debug(cs, addr, buf, l, 0) < 0) { monitor_printf(mon, " Cannot access memory\n"); break; } -- 1.8.3.1