Crash in QEMU monitor

[huhrenfeldt]

There seems to be a problem in the QEMU monitor code related to dumping the registers.

Using Cheribuild (commit ID: 32fb272f387ce94d2c3332c64a6619009854089c) I built and ran CheriBSD like:

./cheribuild.py --include-dependencies run-riscv64-purecap

During CheriBSD bootup, I hit CTRL-A CTRL-C to bring up the qemu monitor. Here "info registers" often causes a crash (but not 100% consistent):

qemu-system-riscv64cheri: ../../qemu/target/cheri-common/cpu_cheri.h:179: target_ulong PC_ADDR(CPUArchState *): Assertion `pc_is_current(env)' failed.

Thread 1 "qemu-system-ris" received signal SIGABRT, Aborted.
__GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
51      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) backtrace
#0  0x00007ffff5575fb7 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007ffff5577921 in __GI_abort () at abort.c:79
#2  0x00007ffff556748a in __assert_fail_base (fmt=0x7ffff56ee750 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0xd47f77 "pc_is_current(env)", file=file@entry=0xd47e6b "../../qemu/target/cheri-common/cpu_cheri.h", line=line@entry=179, function=function@entry=0xd47f8a "target_ulong PC_ADDR(CPUArchState *)") at assert.c:92
#3  0x00007ffff5567502 in __GI___assert_fail (assertion=0xd47f77 "pc_is_current(env)", file=0xd47e6b "../../qemu/target/cheri-common/cpu_cheri.h", line=179, function=0xd47f8a "target_ulong PC_ADDR(CPUArchState *)") at assert.c:101
#4  0x00000000006d3fff in PC_ADDR (env=0x142c9a0) at ../../qemu/target/cheri-common/cpu_cheri.h:179
#5  0x00000000006d866a in riscv_cpu_dump_state (cs=0x1422b20, f=0x0, flags=131072) at ../../qemu/target/riscv/cpu.c:260
#6  0x00000000005669b1 in cpu_dump_state (cpu=0x1422b20, f=0x0, flags=131072) at ../../qemu/hw/core/cpu.c:233
#7  0x0000000000818a21 in hmp_info_registers (mon=0x1415c30, qdict=0x2063df0) at ../../qemu/monitor/misc.c:330
#8  0x000000000041cb89 in handle_hmp_command (mon=0x1415c30, cmdline=0x141ffbe "") at ../../qemu/monitor/hmp.c:1100
#9  0x000000000041c405 in monitor_command_cb (opaque=0x1415c30, cmdline=0x141ffb0 "info registers", readline_opaque=0x0) at ../../qemu/monitor/hmp.c:47
#10 0x0000000000ad872a in readline_handle_byte (rs=0x141ffb0, ch=13) at ../../qemu/util/readline.c:408
#11 0x000000000041e97c in monitor_read (opaque=0x1415c30, buf=0x7fffffffc990 "\r\315\377\377\377\177", size=1) at ../../qemu/monitor/hmp.c:1340
#12 0x0000000000a3f31d in mux_chr_read (opaque=0x13e9e40, buf=0x7fffffffc990 "\r\315\377\377\377\177", size=1) at ../../qemu/chardev/char-mux.c:228
#13 0x0000000000a402b2 in qemu_chr_be_write_impl (s=0x1359f40, buf=0x7fffffffc990 "\r\315\377\377\377\177", len=1) at ../../qemu/chardev/char.c:201
#14 0x0000000000a40328 in qemu_chr_be_write (s=0x1359f40, buf=0x7fffffffc990 "\r\315\377\377\377\177", len=1) at ../../qemu/chardev/char.c:213
#15 0x0000000000a44c0f in fd_chr_read (chan=0x137bfa0, cond=G_IO_IN, opaque=0x1359f40) at ../../qemu/chardev/char-fd.c:68
#16 0x0000000000a2618b in qio_channel_fd_source_dispatch (source=0x24ecf20, callback=0xa44ae0 <fd_chr_read>, user_data=0x1359f40)
    at ../../qemu/io/channel-watch.c:84
#17 0x00007ffff72703a5 in g_main_context_dispatch () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#18 0x0000000000ac70fc in glib_pollfds_poll () at ../../qemu/util/main-loop.c:221
#19 0x0000000000ac6ad8 in os_host_main_loop_wait (timeout=7626668) at ../../qemu/util/main-loop.c:244
#20 0x0000000000ac69b3 in main_loop_wait (nonblocking=0) at ../../qemu/util/main-loop.c:520
#21 0x00000000008e11d4 in qemu_main_loop () at ../../qemu/softmmu/vl.c:1732

#22 0x000000000040e9ef in main (argc=20, argv=0x7fffffffdc58, envp=0x7fffffffdd00) at ../../qemu/softmmu/main.c:50