Date: Mon, 22 Jul 2024 15:40:58 +0200 From: Michal Meloun <meloun.michal@gmail.com> To: Mark Millard <marklmi@yahoo.com> Cc: FreeBSD Current <freebsd-current@freebsd.org>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, "kib@freebsd.org >> Konstantin Belousov" <kib@freebsd.org> Subject: Re: armv7-on-aarch64 stuck at urdlck Message-ID: <86185657-e521-466b-89e2-f291aaac10a6@freebsd.org> In-Reply-To: <B5E2275D-21F0-43C8-AF06-A45DB7448D66@yahoo.com> References: <724db42b-5550-4381-8277-2971e6b3e8f1@freebsd.org> <B5E2275D-21F0-43C8-AF06-A45DB7448D66@yahoo.com>
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On 22.07.2024 13:46, Mark Millard wrote:
> On Jul 21, 2024, at 22:59, Michal Meloun <meloun.michal@gmail.com> wrote:
>
>> I don't want to hijack the original thread, so I'm replying in a new one.
>>
>> My tegra track current, has been running 24/7 by building kernel/world and kde5 in a loop for a few years now. But I have never encountered the aforementioned lockup in native armv7.
>>
>> I have seen usermode mutex lockup in arm32 jail on aarch64, but only very rarely (once a month or so) and all my attempts to reproduce it in a more deterministic way have failed. Also, I don't think I've ever seen this with the debug version of libc.
>>
>> Unfortunately I also failed to reproduce given lockup using dlopen_test.c, neither on native armv7 or arm32 jail.
>>
>> Michal Meloun
>
> What is the output of:
>
> # readelf -a /libexec/ld-elf.so.1 | grep -E "(^[^ 0-9]|.*_rtld_get_stack_prot)"
>
> in your armv7 context(s)? Does it include for likes of:
>
> QUOTE
> Symbol table '.symtab' contains 911 entries:
> 903: 000000000001b9ac 16 FUNC GLOBAL DEFAULT 11 _rtld_get_stack_prot
> END QUOTE
> `
> vs. not?
>
> Note that the "debug version of libc" being involved likely means that
> DEBUG_FLAGS was defined. That in turn likely means that strip is not
> being used. In such a case, I expect that the .symtab entry for
> _rtld_get_stack_prot (and more) exists for such a context.
>
At tis time, I have standard (thus stripped, non-debug) version of
runtime linker library installed. Thus it have only dynamic relocation
record for _rtld_get_stack_prot:
root@tegra124:~/dlopen_test # readelf -a /libexec/ld-elf.so.1 | grep -E
"(^[^ 0-9]|.*_rtld_get_stack_prot)"
ELF Header:
Elf file type is DYN (Shared object file)
Entry point 0x1449c
There are 10 program headers, starting at offset 52
Program Headers:
There are 23 section headers, starting at offset 0x1a448:
Section Headers:
Key to Flags:
Dynamic section at offset 0x19fa4 contains 15 entries:
Relocation section (.rel.dyn):
r_offset r_info r_type st_value st_name
Symbol table '.dynsym' contains 27 entries:
5: 000000000001ba0c 16 FUNC GLOBAL DEFAULT 12
_rtld_get_stack_prot@@FBSDprivate_1.0 (11)
Notes at offset 0x00000174 with length 0x00000018:
Histogram for bucket list length (total of 6 buckets):
Histogram for bucket list length (total of 27 buckets):
Version symbol section (.gnu.version):
Version definition section (.gnu.version_d):
Attribute Section: aeabi
------
root@tegra124:~/dlopen_test # ./dlopen_test
root@tegra124:~/dlopen_test #
Michal Meloun
Michal Meloun
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