The patch referred to in comment #4 has now been committed, so from QEMU 3.0 this will fail with a useful error message to tell the user their choice of machine and CPU aren't compatible.
** Changed in: qemu Status: New => Fix Committed -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1766896 Title: qemu-system-arm segfault in arm_v7m_mmu_idx_for_secstate Status in QEMU: Fix Committed Bug description: Attempting to emulate some baremetal ARM cortex-M* firmware with gdb causes a segfault every time. qemu invocation: qemu-system-arm -machine none -cpu cortex-m3 -nographic -monitor null -serial null -s -S -device loader,file=firmware.elf qemu seems to startup fine with that command. Segfault happens as soon as I connect from another console with arm-none-eabi-gdb firmware.elf > target remote localhost:1234 # qemu segfaults, and kills arm-none-eabi-gdb along with it Here's a bt from qemu-system-arm : ********************************* #0 armv7m_nvic_neg_prio_requested (opaque=0x0, secure=false) at /home/sac/qemu/src/qemu/hw/intc/armv7m_nvic.c:383 s = 0x0 #1 0x006e4806 in arm_v7m_mmu_idx_for_secstate (secstate=<optimized out>, env=0xb620263c) at /home/sac/qemu/src/qemu/target/arm/cpu.h:2345 el = <optimized out> mmu_idx = ARMMMUIdx_MPriv el = <optimized out> mmu_idx = <optimized out> #2 cpu_mmu_index (ifetch=false, env=0xb620263c) at /home/sac/qemu/src/qemu/target/arm/cpu.h:2358 mmu_idx = <optimized out> el = <optimized out> ifetch = <optimized out> env = 0xb620263c el = <optimized out> mmu_idx = <optimized out> el = <optimized out> el = <optimized out> mmu_idx = <optimized out> #3 arm_cpu_get_phys_page_attrs_debug (cs=0xb61fe480, addr=0, attrs=0xbfffc668) at /home/sac/qemu/src/qemu/target/arm/helper.c:9858 cpu = 0xb61fe480 __func__ = "arm_cpu_get_phys_page_attrs_debug" env = 0xb620263c phys_addr = 6402535376434480864 page_size = 5 prot = -1239242724 ret = <optimized out> fsr = 4294967041 fi = {s2addr = 0, stage2 = false, s1ptw = false, ea = false} mmu_idx = <optimized out> #4 0x005729d1 in cpu_get_phys_page_attrs_debug (attrs=<optimized out>, addr=<optimized out>, cpu=<optimized out>) at /home/sac/qemu/src/qemu/include/qom/cpu.h:580 cc = <optimized out> cc = <optimized out> #5 cpu_memory_rw_debug (cpu=0xb61fe480, addr=0, buf=0xbfffd6dc "", len=4, is_write=0) at /home/sac/qemu/src/qemu/exec.c:3524 asidx = <optimized out> attrs = {unspecified = 0, secure = 0, user = 0, requester_id = 15525} l = <optimized out> phys_addr = <optimized out> page = 0 __PRETTY_FUNCTION__ = "cpu_memory_rw_debug" #6 0x005b4c5e in target_memory_rw_debug (is_write=false, len=4, buf=<optimized out>, addr=0, cpu=0xb61fe480) at /home/sac/qemu/src/qemu/gdbstub.c:56 cc = <optimized out> cc = <optimized out> #7 gdb_handle_packet (s=s@entry=0xb6229800, line_buf=line_buf@entry=0xb6229810 "m0,4") at /home/sac/qemu/src/qemu/gdbstub.c:1109 cpu = <optimized out> cc = <optimized out> p = 0xb6229813 "4" thread = <optimized out> ch = <optimized out> reg_size = <optimized out> type = <optimized out> res = <optimized out> buf = "m1\000", '\060' <repeats 109 times>, "ffffffff00000000d3010040\000t modification,\n are permitted in any medium without royalt"... mem_buf = '\000' <repeats 56 times>, "\377\377\377\377\000\000\000\000\323\001\000@", '\000' <repeats 716 times>... registers = <optimized out> addr = 0 len = 4 __func__ = "gdb_handle_packet" #8 0x005b55b3 in gdb_read_byte (ch=100, s=0xb6229800) at /home/sac/qemu/src/qemu/gdbstub.c:1664 reply = 43 '+' reply = <optimized out> repeat = <optimized out> #9 gdb_chr_receive (opaque=<optimized out>, buf=<optimized out>, size=<optimized out>) at /home/sac/qemu/src/qemu/gdbstub.c:1868 i = <optimized out> #10 0x00980319 in tcp_chr_read (chan=0xb6c86200, cond=G_IO_IN, opaque=0xb63fc6e0) at chardev/char-socket.c:440 chr = <optimized out> __func__ = "tcp_chr_read" s = 0xb63fc6e0 buf = "$m0,4#fddInfo#c8read:arm-core.xml:0,ffb#08+;qRelocInsn+;fork-events+;vfork-events+;exec-events+;vContSupported+;QThreadEvents+;no-resumed+#df\363\377\377\000\000\000\000\274\354\377\277", '\000' <repeats 16 times>, "\272\356\377 \274\354\377\277", '\000' <repeats 16 times>, "\373\377\377\377\005\000\000\000"... len = <optimized out> size = <optimized out> #11 0xb7808c44 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0 No symbol table info available. #12 0x009e14d2 in glib_pollfds_poll () at util/main-loop.c:214 context = 0xb645f740 pfds = <optimized out> context = <optimized out> pfds = <optimized out> #13 os_host_main_loop_wait (timeout=<optimized out>) at util/main-loop.c:261 context = 0xb645f740 ret = 1 spin_counter = 0 context = <optimized out> ret = <optimized out> spin_counter = 0 notified = false #14 main_loop_wait (nonblocking=0) at util/main-loop.c:515 ret = <optimized out> timeout = 1000 timeout_ns = <optimized out> #15 0x00561781 in main_loop () at vl.c:1995 No locals. #16 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4911 i = <optimized out> snapshot = <optimized out> linux_boot = <optimized out> initrd_filename = <optimized out> kernel_filename = <optimized out> kernel_cmdline = <optimized out> boot_order = <optimized out> boot_once = <optimized out> ds = <optimized out> cyls = <optimized out> heads = <optimized out> secs = <optimized out> translation = <optimized out> opts = <optimized out> machine_opts = <optimized out> hda_opts = <optimized out> icount_opts = <optimized out> accel_opts = <optimized out> olist = <optimized out> optind = 14 optarg = 0xbffffcf6 "loader,file=firmware.elf" loadvm = <optimized out> machine_class = <optimized out> cpu_model = <optimized out> vga_model = <optimized out> qtest_chrdev = <optimized out> qtest_log = <optimized out> pid_file = <optimized out> incoming = <optimized out> userconfig = <optimized out> nographic = <optimized out> display_type = <optimized out> display_remote = <optimized out> log_mask = <optimized out> log_file = <optimized out> trace_file = <optimized out> maxram_size = <optimized out> ram_slots = <optimized out> vmstate_dump_file = <optimized out> main_loop_err = 0x0 err = 0x0 list_data_dirs = <optimized out> dirs = <optimized out> bdo_queue = {sqh_first = 0x0, sqh_last = 0xbffff918} __func__ = "main" To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1766896/+subscriptions