Hi Zhen,

On Thu, Dec 15, 2022 at 2:58 PM Leizhen (ThunderTown)
[off-list ref] wrote:

On 2022/12/15 21:24, Geert Uytterhoeven wrote:

quoted

On Thu, Dec 15, 2022 at 1:34 PM Leizhen (ThunderTown)
[off-list ref] wrote:

quoted

On 2022/12/15 17:39, Geert Uytterhoeven wrote:

quoted

On Thu, Dec 15, 2022 at 10:16 AM Leizhen (ThunderTown)
[off-list ref] wrote:

quoted

On 2022/12/15 16:50, Geert Uytterhoeven wrote:

quoted

On Tue, Nov 15, 2022 at 9:41 AM Zhen Lei [off-list ref] wrote:

quoted

Added test cases for basic functions and performance of functions
kallsyms_lookup_name(), kallsyms_on_each_symbol() and
kallsyms_on_each_match_symbol(). It also calculates the compression rate
of the kallsyms compression algorithm for the current symbol set.

The basic functions test begins by testing a set of symbols whose address
values are known. Then, traverse all symbol addresses and find the
corresponding symbol name based on the address. It's impossible to
determine whether these addresses are correct, but we can use the above
three functions along with the addresses to test each other. Due to the
traversal operation of kallsyms_on_each_symbol() is too slow, only 60
symbols can be tested in one second, so let it test on average once
every 128 symbols. The other two functions validate all symbols.

If the basic functions test is passed, print only performance test
results. If the test fails, print error information, but do not perform
subsequent performance tests.

Start self-test automatically after system startup if
CONFIG_KALLSYMS_SELFTEST=y.

Example of output content: (prefix 'kallsyms_selftest:' is omitted
 start
  ---------------------------------------------------------
 | nr_symbols | compressed size | original size | ratio(%) |
 |---------------------------------------------------------|
 |     107543 |       1357912   |      2407433  |  56.40   |
  ---------------------------------------------------------
 kallsyms_lookup_name() looked up 107543 symbols
 The time spent on each symbol is (ns): min=630, max=35295, avg=7353
 kallsyms_on_each_symbol() traverse all: 11782628 ns
 kallsyms_on_each_match_symbol() traverse all: 9261 ns
 finish

Signed-off-by: Zhen Lei <redacted>

Thanks for your patch, which is now commit 30f3bb09778de64e ("kallsyms:
Add self-test facility") in linus/master.

I gave this a try on m68k (atari_defconfig + CONFIG_KALLSYMS_SELFTEST=y),
but it failed:

    start
    kallsyms_lookup_name() for kallsyms_test_func_static failed:
addr=0, expect 60ab0
    kallsyms_lookup_name() for kallsyms_test_func failed: addr=0, expect 60ac0
    kallsyms_lookup_name() for kallsyms_test_func_weak failed: addr=0,
expect 60ac2
    kallsyms_lookup_name() for vmalloc failed: addr=0, expect c272a
    kallsyms_lookup_name() for vfree failed: addr=0, expect c2142
    kallsyms_on_each_match_symbol() for kallsyms_test_func_static
failed: count=0, addr=0, expect 60ab0
    kallsyms_on_each_match_symbol() for kallsyms_test_func failed:
count=0, addr=0, expect 60ac0
    kallsyms_on_each_match_symbol() for kallsyms_test_func_weak
failed: count=0, addr=0, expect 60ac2
    kallsyms_on_each_match_symbol() for vmalloc failed: count=0,
addr=0, expect c272a
    kallsyms_on_each_match_symbol() for vfree failed: count=0, addr=0,
expect c2142
    abort

Oh, maybe you can "git reset --hard 30f3bb09778de64" and try again.
30f3bb09778de64 kallsyms: Add self-test facility

But the latest kernel is OK on x86. So other patches are unlikely to
affect this function.

On 30f3bb09778de64 it fails the same way:

    start
    kallsyms_lookup_name() for kallsyms_test_func_static failed:
addr=8dbc, expect 60308
    kallsyms_lookup_name() for kallsyms_test_func failed: addr=8dbc,
expect 60318
    kallsyms_lookup_name() for kallsyms_test_func_weak failed:
addr=8dbc, expect 6031a
    kallsyms_lookup_name() for vmalloc failed: addr=8dbc, expect bdc88
    kallsyms_lookup_name() for vfree failed: addr=8dbc, expect bd6de
    kallsyms_on_each_match_symbol() for kallsyms_test_func_static
failed: count=24890, addr=1ee870, expect 60308
    kallsyms_on_each_match_symbol() for kallsyms_test_func failed:
count=24890, addr=1ee870, expect 60318
    kallsyms_on_each_match_symbol() for kallsyms_test_func_weak
failed: count=24890, addr=1ee870, expect 6031a
    kallsyms_on_each_match_symbol() for vmalloc failed: count=24890,
addr=1ee870, expect bdc88
    kallsyms_on_each_match_symbol() for vfree failed: count=24890,
addr=1ee870, expect bd6de
    abort

Is m68k big-endian?

Yes it is. And 32-bit values are aligned to only 2 bytes.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds