Make sure that qemu gdbstub, like gdbserver, allows reading from and
writing to PROT_NONE pages.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
tests/tcg/multiarch/Makefile.target | 9 +++++-
tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
3 files changed, 70 insertions(+), 1 deletion(-)
create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
create mode 100644 tests/tcg/multiarch/prot-none.c
diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
index d31ba8d6ae4..315a2e13588 100644
--- a/tests/tcg/multiarch/Makefile.target
+++ b/tests/tcg/multiarch/Makefile.target
@@ -101,13 +101,20 @@ run-gdbstub-registers: sha512
--bin $< --test $(MULTIARCH_SRC)/gdbstub/registers.py, \
checking register enumeration)
+run-gdbstub-prot-none: prot-none
+ $(call run-test, $@, env PROT_NONE_PY=1 $(GDB_SCRIPT) \
+ --gdb $(GDB) \
+ --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
+ --bin $< --test $(MULTIARCH_SRC)/gdbstub/prot-none.py, \
+ accessing PROT_NONE memory)
+
else
run-gdbstub-%:
$(call skip-test, "gdbstub test $*", "need working gdb with $(patsubst -%,,$(TARGET_NAME)) support")
endif
EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read \
run-gdbstub-proc-mappings run-gdbstub-thread-breakpoint \
- run-gdbstub-registers
+ run-gdbstub-registers run-gdbstub-prot-none
# ARM Compatible Semi Hosting Tests
#
diff --git a/tests/tcg/multiarch/gdbstub/prot-none.py b/tests/tcg/multiarch/gdbstub/prot-none.py
new file mode 100644
index 00000000000..f1f1dd82cbe
--- /dev/null
+++ b/tests/tcg/multiarch/gdbstub/prot-none.py
@@ -0,0 +1,22 @@
+"""Test that GDB can access PROT_NONE pages.
+
+This runs as a sourced script (via -x, via run-test.py).
+
+SPDX-License-Identifier: GPL-2.0-or-later
+"""
+from test_gdbstub import main, report
+
+
+def run_test():
+ """Run through the tests one by one"""
+ gdb.Breakpoint("break_here")
+ gdb.execute("continue")
+ val = gdb.parse_and_eval("*(char[2] *)q").string()
+ report(val == "42", "{} == 42".format(val))
+ gdb.execute("set *(char[3] *)q = \"24\"")
+ gdb.execute("continue")
+ exitcode = int(gdb.parse_and_eval("$_exitcode"))
+ report(exitcode == 0, "{} == 0".format(exitcode))
+
+
+main(run_test)
diff --git a/tests/tcg/multiarch/prot-none.c b/tests/tcg/multiarch/prot-none.c
new file mode 100644
index 00000000000..dc56aadb3c5
--- /dev/null
+++ b/tests/tcg/multiarch/prot-none.c
@@ -0,0 +1,40 @@
+/*
+ * Test that GDB can access PROT_NONE pages.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+void break_here(void *q)
+{
+}
+
+int main(void)
+{
+ long pagesize = sysconf(_SC_PAGESIZE);
+ void *p, *q;
+ int err;
+
+ p = mmap(NULL, pagesize * 2, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ assert(p != MAP_FAILED);
+ q = p + pagesize - 1;
+ strcpy(q, "42");
+
+ err = mprotect(p, pagesize * 2, PROT_NONE);
+ assert(err == 0);
+
+ break_here(q);
+
+ err = mprotect(p, pagesize * 2, PROT_READ);
+ assert(err == 0);
+ if (getenv("PROT_NONE_PY")) {
+ assert(strcmp(q, "24") == 0);
+ }
+
+ return EXIT_SUCCESS;
+}
--
2.43.0Ilya Leoshkevich <iii@linux.ibm.com> writes:
> Make sure that qemu gdbstub, like gdbserver, allows reading from and
> writing to PROT_NONE pages.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
> tests/tcg/multiarch/Makefile.target | 9 +++++-
> tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
> tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
> 3 files changed, 70 insertions(+), 1 deletion(-)
> create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
> create mode 100644 tests/tcg/multiarch/prot-none.c
>
> diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
> index d31ba8d6ae4..315a2e13588 100644
> --- a/tests/tcg/multiarch/Makefile.target
> +++ b/tests/tcg/multiarch/Makefile.target
> @@ -101,13 +101,20 @@ run-gdbstub-registers: sha512
> --bin $< --test $(MULTIARCH_SRC)/gdbstub/registers.py, \
> checking register enumeration)
>
> +run-gdbstub-prot-none: prot-none
> + $(call run-test, $@, env PROT_NONE_PY=1 $(GDB_SCRIPT) \
> + --gdb $(GDB) \
> + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
> + --bin $< --test $(MULTIARCH_SRC)/gdbstub/prot-none.py, \
> + accessing PROT_NONE memory)
> +
> else
> run-gdbstub-%:
> $(call skip-test, "gdbstub test $*", "need working gdb with $(patsubst -%,,$(TARGET_NAME)) support")
> endif
> EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read \
> run-gdbstub-proc-mappings run-gdbstub-thread-breakpoint \
> - run-gdbstub-registers
> + run-gdbstub-registers run-gdbstub-prot-none
>
> # ARM Compatible Semi Hosting Tests
> #
> diff --git a/tests/tcg/multiarch/gdbstub/prot-none.py b/tests/tcg/multiarch/gdbstub/prot-none.py
> new file mode 100644
> index 00000000000..f1f1dd82cbe
> --- /dev/null
> +++ b/tests/tcg/multiarch/gdbstub/prot-none.py
> @@ -0,0 +1,22 @@
> +"""Test that GDB can access PROT_NONE pages.
> +
> +This runs as a sourced script (via -x, via run-test.py).
> +
> +SPDX-License-Identifier: GPL-2.0-or-later
> +"""
> +from test_gdbstub import main, report
> +
> +
> +def run_test():
> + """Run through the tests one by one"""
> + gdb.Breakpoint("break_here")
> + gdb.execute("continue")
> + val = gdb.parse_and_eval("*(char[2] *)q").string()
Better traceback:
Breakpoint 1, break_here (q=0x400000802fff) at /home/alex/lsrc/qemu.git/tests/tcg/multiarch/prot-none.c:14
14 }
GDB Exception:
Traceback (most recent call last):
File "/home/alex/lsrc/qemu.git/tests/guest-debug/test_gdbstub.py", line 42, in main
test()
File "./tests/tcg/multiarch/gdbstub/prot-none.py", line 14, in run_test
val = gdb.parse_and_eval("*(char[2] *)q").string()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
gdb.MemoryError: Cannot access memory at address 0x400000802fff
Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>
> + report(val == "42", "{} == 42".format(val))
> + gdb.execute("set *(char[3] *)q = \"24\"")
> + gdb.execute("continue")
> + exitcode = int(gdb.parse_and_eval("$_exitcode"))
> + report(exitcode == 0, "{} == 0".format(exitcode))
> +
> +
> +main(run_test)
> diff --git a/tests/tcg/multiarch/prot-none.c b/tests/tcg/multiarch/prot-none.c
> new file mode 100644
> index 00000000000..dc56aadb3c5
> --- /dev/null
> +++ b/tests/tcg/multiarch/prot-none.c
> @@ -0,0 +1,40 @@
> +/*
> + * Test that GDB can access PROT_NONE pages.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#include <assert.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <unistd.h>
> +
> +void break_here(void *q)
> +{
> +}
> +
> +int main(void)
> +{
> + long pagesize = sysconf(_SC_PAGESIZE);
> + void *p, *q;
> + int err;
> +
> + p = mmap(NULL, pagesize * 2, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> + assert(p != MAP_FAILED);
> + q = p + pagesize - 1;
> + strcpy(q, "42");
> +
> + err = mprotect(p, pagesize * 2, PROT_NONE);
> + assert(err == 0);
> +
> + break_here(q);
> +
> + err = mprotect(p, pagesize * 2, PROT_READ);
> + assert(err == 0);
> + if (getenv("PROT_NONE_PY")) {
> + assert(strcmp(q, "24") == 0);
> + }
> +
> + return EXIT_SUCCESS;
> +}
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
On Mon, Jan 22, 2024 at 03:54:32PM +0000, Alex Bennée wrote:
> Ilya Leoshkevich <iii@linux.ibm.com> writes:
>
> > Make sure that qemu gdbstub, like gdbserver, allows reading from and
> > writing to PROT_NONE pages.
> >
> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> > ---
> > tests/tcg/multiarch/Makefile.target | 9 +++++-
> > tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
> > tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
> > 3 files changed, 70 insertions(+), 1 deletion(-)
> > create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
> > create mode 100644 tests/tcg/multiarch/prot-none.c
[...]
> > +def run_test():
> > + """Run through the tests one by one"""
> > + gdb.Breakpoint("break_here")
> > + gdb.execute("continue")
> > + val = gdb.parse_and_eval("*(char[2] *)q").string()
>
> Better traceback:
>
> Breakpoint 1, break_here (q=0x400000802fff) at /home/alex/lsrc/qemu.git/tests/tcg/multiarch/prot-none.c:14
> 14 }
> GDB Exception:
> Traceback (most recent call last):
> File "/home/alex/lsrc/qemu.git/tests/guest-debug/test_gdbstub.py", line 42, in main
> test()
> File "./tests/tcg/multiarch/gdbstub/prot-none.py", line 14, in run_test
> val = gdb.parse_and_eval("*(char[2] *)q").string()
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> gdb.MemoryError: Cannot access memory at address 0x400000802fff
> Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
> Type "help", "copyright", "credits" or "license" for more information.
> (InteractiveConsole)
> >>>
Thanks for the debug output. This shows that the feature being tested
doesn't work (the value of `q` looks sane to me). May I ask what host
distro is this? I tried on x86_64 Fedora 38 and x86_64 Ubuntu 22.04 so
far, and the test was successful.
[...]
Ilya Leoshkevich <iii@linux.ibm.com> writes:
> On Mon, Jan 22, 2024 at 03:54:32PM +0000, Alex Bennée wrote:
>> Ilya Leoshkevich <iii@linux.ibm.com> writes:
>>
>> > Make sure that qemu gdbstub, like gdbserver, allows reading from and
>> > writing to PROT_NONE pages.
>> >
>> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>> > ---
>> > tests/tcg/multiarch/Makefile.target | 9 +++++-
>> > tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
>> > tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
>> > 3 files changed, 70 insertions(+), 1 deletion(-)
>> > create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
>> > create mode 100644 tests/tcg/multiarch/prot-none.c
>
> [...]
>
>> > +def run_test():
>> > + """Run through the tests one by one"""
>> > + gdb.Breakpoint("break_here")
>> > + gdb.execute("continue")
>> > + val = gdb.parse_and_eval("*(char[2] *)q").string()
>>
>> Better traceback:
>>
>> Breakpoint 1, break_here (q=0x400000802fff) at /home/alex/lsrc/qemu.git/tests/tcg/multiarch/prot-none.c:14
>> 14 }
>> GDB Exception:
>> Traceback (most recent call last):
>> File "/home/alex/lsrc/qemu.git/tests/guest-debug/test_gdbstub.py", line 42, in main
>> test()
>> File "./tests/tcg/multiarch/gdbstub/prot-none.py", line 14, in run_test
>> val = gdb.parse_and_eval("*(char[2] *)q").string()
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> gdb.MemoryError: Cannot access memory at address 0x400000802fff
>> Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
>> Type "help", "copyright", "credits" or "license" for more information.
>> (InteractiveConsole)
>> >>>
>
> Thanks for the debug output. This shows that the feature being tested
> doesn't work (the value of `q` looks sane to me). May I ask what host
> distro is this? I tried on x86_64 Fedora 38 and x86_64 Ubuntu 22.04 so
> far, and the test was successful.
Debian Bookworm (x86_64) with gdb-multiarch installed.
>
> [...]
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
On Mon, Jan 22, 2024 at 11:19:05PM +0000, Alex Bennée wrote:
> Ilya Leoshkevich <iii@linux.ibm.com> writes:
>
> > On Mon, Jan 22, 2024 at 03:54:32PM +0000, Alex Bennée wrote:
> >> Ilya Leoshkevich <iii@linux.ibm.com> writes:
> >>
> >> > Make sure that qemu gdbstub, like gdbserver, allows reading from and
> >> > writing to PROT_NONE pages.
> >> >
> >> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> >> > ---
> >> > tests/tcg/multiarch/Makefile.target | 9 +++++-
> >> > tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
> >> > tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
> >> > 3 files changed, 70 insertions(+), 1 deletion(-)
> >> > create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
> >> > create mode 100644 tests/tcg/multiarch/prot-none.c
> >
> > [...]
> >
> >> > +def run_test():
> >> > + """Run through the tests one by one"""
> >> > + gdb.Breakpoint("break_here")
> >> > + gdb.execute("continue")
> >> > + val = gdb.parse_and_eval("*(char[2] *)q").string()
> >>
> >> Better traceback:
> >>
> >> Breakpoint 1, break_here (q=0x400000802fff) at /home/alex/lsrc/qemu.git/tests/tcg/multiarch/prot-none.c:14
> >> 14 }
> >> GDB Exception:
> >> Traceback (most recent call last):
> >> File "/home/alex/lsrc/qemu.git/tests/guest-debug/test_gdbstub.py", line 42, in main
> >> test()
> >> File "./tests/tcg/multiarch/gdbstub/prot-none.py", line 14, in run_test
> >> val = gdb.parse_and_eval("*(char[2] *)q").string()
> >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >> gdb.MemoryError: Cannot access memory at address 0x400000802fff
> >> Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
> >> Type "help", "copyright", "credits" or "license" for more information.
> >> (InteractiveConsole)
> >> >>>
> >
> > Thanks for the debug output. This shows that the feature being tested
> > doesn't work (the value of `q` looks sane to me). May I ask what host
> > distro is this? I tried on x86_64 Fedora 38 and x86_64 Ubuntu 22.04 so
> > far, and the test was successful.
>
> Debian Bookworm (x86_64) with gdb-multiarch installed.
> >
> > [...]
>
> --
> Alex Bennée
> Virtualisation Tech Lead @ Linaro
Hm, I tried that (in a VM, in case the kernel is somehow involved) and
that worked too:
Breakpoint 1, break_here (q=0x400000802fff) at /qemu/tests/tcg/multiarch/prot-none.c:14
14 }
PASS: 42 == 42
I wonder what else can be different. Can it be that in your case the
test runs without /proc? Or perhaps some additional LSM is enabled?
Ilya Leoshkevich <iii@linux.ibm.com> writes:
> Make sure that qemu gdbstub, like gdbserver, allows reading from and
> writing to PROT_NONE pages.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Hmm I'm seeing the test hang and drop to the interactive python shell:
TEST basic gdbstub support on aarch64
Failed to read a valid object file image from memory.
qemu-aarch64: QEMU: Terminated via GDBstub
TEST basic gdbstub qXfer:auxv:read support on aarch64
Failed to read a valid object file image from memory.
qemu-aarch64: QEMU: Terminated via GDBstub
TEST proc mappings support on aarch64
Failed to read a valid object file image from memory.
qemu-aarch64: QEMU: Terminated via GDBstub
TEST hitting a breakpoint on non-main thread on aarch64
Failed to read a valid object file image from memory.
qemu-aarch64: QEMU: Terminated via GDBstub
TEST checking register enumeration on aarch64
Failed to read a valid object file image from memory.
qemu-aarch64: QEMU: Terminated via GDBstub
TEST accessing PROT_NONE memory on aarch64
Failed to read a valid object file image from memory.
Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
> ---
> tests/tcg/multiarch/Makefile.target | 9 +++++-
> tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
> tests/tcg/multiarch/prot-none.c | 40 ++++++++++++++++++++++++
> 3 files changed, 70 insertions(+), 1 deletion(-)
> create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
> create mode 100644 tests/tcg/multiarch/prot-none.c
>
> diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
> index d31ba8d6ae4..315a2e13588 100644
> --- a/tests/tcg/multiarch/Makefile.target
> +++ b/tests/tcg/multiarch/Makefile.target
> @@ -101,13 +101,20 @@ run-gdbstub-registers: sha512
> --bin $< --test $(MULTIARCH_SRC)/gdbstub/registers.py, \
> checking register enumeration)
>
> +run-gdbstub-prot-none: prot-none
> + $(call run-test, $@, env PROT_NONE_PY=1 $(GDB_SCRIPT) \
> + --gdb $(GDB) \
> + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
> + --bin $< --test $(MULTIARCH_SRC)/gdbstub/prot-none.py, \
> + accessing PROT_NONE memory)
> +
> else
> run-gdbstub-%:
> $(call skip-test, "gdbstub test $*", "need working gdb with $(patsubst -%,,$(TARGET_NAME)) support")
> endif
> EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read \
> run-gdbstub-proc-mappings run-gdbstub-thread-breakpoint \
> - run-gdbstub-registers
> + run-gdbstub-registers run-gdbstub-prot-none
>
> # ARM Compatible Semi Hosting Tests
> #
> diff --git a/tests/tcg/multiarch/gdbstub/prot-none.py b/tests/tcg/multiarch/gdbstub/prot-none.py
> new file mode 100644
> index 00000000000..f1f1dd82cbe
> --- /dev/null
> +++ b/tests/tcg/multiarch/gdbstub/prot-none.py
> @@ -0,0 +1,22 @@
> +"""Test that GDB can access PROT_NONE pages.
> +
> +This runs as a sourced script (via -x, via run-test.py).
> +
> +SPDX-License-Identifier: GPL-2.0-or-later
> +"""
> +from test_gdbstub import main, report
> +
> +
> +def run_test():
> + """Run through the tests one by one"""
> + gdb.Breakpoint("break_here")
> + gdb.execute("continue")
> + val = gdb.parse_and_eval("*(char[2] *)q").string()
> + report(val == "42", "{} == 42".format(val))
> + gdb.execute("set *(char[3] *)q = \"24\"")
> + gdb.execute("continue")
> + exitcode = int(gdb.parse_and_eval("$_exitcode"))
> + report(exitcode == 0, "{} == 0".format(exitcode))
> +
> +
> +main(run_test)
> diff --git a/tests/tcg/multiarch/prot-none.c b/tests/tcg/multiarch/prot-none.c
> new file mode 100644
> index 00000000000..dc56aadb3c5
> --- /dev/null
> +++ b/tests/tcg/multiarch/prot-none.c
> @@ -0,0 +1,40 @@
> +/*
> + * Test that GDB can access PROT_NONE pages.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#include <assert.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <unistd.h>
> +
> +void break_here(void *q)
> +{
> +}
> +
> +int main(void)
> +{
> + long pagesize = sysconf(_SC_PAGESIZE);
> + void *p, *q;
> + int err;
> +
> + p = mmap(NULL, pagesize * 2, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> + assert(p != MAP_FAILED);
> + q = p + pagesize - 1;
> + strcpy(q, "42");
> +
> + err = mprotect(p, pagesize * 2, PROT_NONE);
> + assert(err == 0);
> +
> + break_here(q);
> +
> + err = mprotect(p, pagesize * 2, PROT_READ);
> + assert(err == 0);
> + if (getenv("PROT_NONE_PY")) {
> + assert(strcmp(q, "24") == 0);
> + }
> +
> + return EXIT_SUCCESS;
> +}
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
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