Re: [PATCH v3 2/2] gdb/testsuite: Add gdb.base/memops-watchpoint.exp

[Kevin Buettner <kevinb@redhat.com>]

On Mon, 22 Apr 2024 20:07:00 -0300
Thiago Jung Bauermann <thiago.bauermann@linaro.org> wrote:

> +set saw_watch_trigger 0
> +set saw_function 0
> +set is_supported 1
> +set message "continue until memcpy watchpoint hits"
> +set watch_trigger \
> +	[multi_line \
> +	     "Continuing\\." \
> +	     "" \
> +	     "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \
> +	     "" \
> +	     "Old value = 101 'e'" \
> +	     "New value = 114 'r'"]
> +gdb_test_multiple "continue" $message {
> +    -re $watch_trigger {
> +	set saw_watch_trigger 1
> +	exp_continue
> +    }
> +    -re ".*memcpy.* \\(\\) at .*:$decimal\r\n" {
> +	set saw_function 1
> +	exp_continue
> +    }
> +    -re ".*memcpy.* \\(\\) from .*libc\[^\r\n\]+\r\n" {
> +	set saw_function 1
> +	exp_continue
> +    }
> +    -re "in \\?\\? \\(\\) from .*libc\[^\r\n\]+\r\n" {
> +	set is_supported 0
> +	unsupported "symbol for memcpy not found"
> +	exp_continue
> +    }
> +    -re "$gdb_prompt $" {
> +	if { $is_supported } {
> +	    setup_kfail breakpoints/31665 arm*-*-linux*
> +	    gdb_assert { $saw_watch_trigger && $saw_function } $message
> +	}
> +    }
> +}

For this test, on Fedora 39 x86_64 without glibc debuginfo, I see:

    continue
    Continuing.

    Hardware watchpoint 3: -location b[28]

    Old value = 101 'e'
    New value = 114 'r'
    0x00007ffff7e34b19 in __memmove_avx_unaligned () from /lib64/libc.so.6
    (gdb) FAIL: gdb.base/memops-watchpoint.exp: continue until memcpy watchpoint hits


When I run it on Fedora 39 x86_64 w/ glibc debuginfo, I see the expected PASS:

    continue
    Continuing.

    Hardware watchpoint 3: -location b[28]

    Old value = 101 'e'
    New value = 114 'r'
    __memcpy_avx_unaligned () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:226
    226		VMOVU	%VMM(1), -VEC_SIZE(%rdi,%rdx)
    (gdb) PASS: gdb.base/memops-watchpoint.exp: continue until memcpy watchpoint hits

I think you can fix the FAIL for the no-glibc-debuginfo case by
tweaking the RE in the same way that you did for the memmove test.

I also have Fedora 39 (Asahi Remix) running on an M1 macbook.  When
I try this test on that machine, I see some timeouts...

    (gdb) watch -location a[28]
    Hardware watchpoint 2: -location a[28]
    (gdb) PASS: gdb.base/memops-watchpoint.exp: set watch on a
    watch -location b[28]
    Hardware watchpoint 3: -location b[28]
    (gdb) PASS: gdb.base/memops-watchpoint.exp: set watchpoint on b
    watch -location c[28]
    Hardware watchpoint 4: -location c[28]
    (gdb) PASS: gdb.base/memops-watchpoint.exp: set watchpoint on c
    continue
    Continuing.

    Hardware watchpoint 2: -location a[28]

    Old value = 104 'h'
    New value = 0 '\000'
    __GI___memset_generic () at ../sysdeps/aarch64/memset.S:67
    67		tbz	count, 5, 1f
    (gdb) PASS: gdb.base/memops-watchpoint.exp: continue until memset watchpoint hits
    continue
    Continuing.
    FAIL: gdb.base/memops-watchpoint.exp: continue until memcpy watchpoint hits (timeout)
    continue
    FAIL: gdb.base/memops-watchpoint.exp: continue until memmove watchpoint hits (timeout)
    testcase /ironwood1/sourceware-git/macbook-review/bld/../../worktree-review/gdb/testsuite/gdb.base/memops-watchpoint.exp completed in 20 seconds

		    === gdb Summary ===

    # of expected passes		4
    # of unexpected failures	2

Is this demonstrating the bug (31484) ?

Kevin