From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
libc-alpha@sourceware.org
Subject: Re: [PATCH] Build libc-start with stack protector for SHARED
Date: Fri, 12 Feb 2021 06:26:43 +0530 [thread overview]
Message-ID: <9d271fde-faf6-9687-e2cd-854f89f390a5@sourceware.org> (raw)
In-Reply-To: <a66d40f3-b1f0-d469-1463-9705be2e7a8e@linaro.org>
On 2/12/21 12:55 AM, Adhemerval Zanella wrote:
>
>
> On 03/02/2021 02:42, Siddhesh Poyarekar via Libc-alpha wrote:
>> This does not change the emitted code since __libc_start_main does not
>> return, but is important for formal flags compliance.
>>
>> This also cleans up the cosmetic inconsistency in the stack protector
>> flags in csu, especially the incorrect value of STACK_PROTECTOR_LEVEL.
>
> I am seeing the following regressions with --enable-stack-protector=all
> on x86_64 and i686 (I haven't seen is on powerpc64le-linux-gnu):
>
> FAIL: elf/ifuncmain9picstatic
> FAIL: elf/ifuncmain9static
> FAIL: elf/tst-ifunc-isa-1-static
> FAIL: elf/tst-ifunc-isa-2-static
>
> $ gdb ./elf/ifuncmain9picstatic
> [...]
> (gdb) r
> [...]
> Program received signal SIGSEGV, Segmentation fault.
> 0x0000000000401944 in resolver () at ifuncmain9.c:47
> 47 {
> (gdb) bt
> #0 0x0000000000401944 in resolver () at ifuncmain9.c:47
> #1 0x0000000000402e88 in elf_ifunc_invoke (addr=<optimized out>) at ../sysdeps/x86_64/dl-irel.h:44
> #2 elf_irela (reloc=0x4004f0) at ../sysdeps/x86_64/dl-irel.h:44
> #3 apply_irel () at ../csu/libc-start.c:86
> #4 __libc_start_main (main=0x401690 <main>, argc=1, argv=0x7fffffffd808, init=0x403cd0 <__libc_csu_init>, fini=0x403d60 <__libc_csu_fini>, rtld_fini=0x0, stack_end=0x7fffffffd7f8) at ../csu/libc-start.c:206
> #5 0x00000000004017ba in _start () at ../sysdeps/x86_64/start.S:120
>
> (gdb) disas
> Dump of assembler code for function resolver:
> 0x0000000000401940 <+0>: sub $0x18,%rsp
> => 0x0000000000401944 <+4>: mov %fs:0x28,%rax
> (gdb) i r fs
> fs 0x0 0
>
> It seems we need to setup the thread pointer earlier.
>
I wasn't able to reproduce this until I repeated the build from scratch.
Sorry, I'll take a look at this again. Thanks for checking.
Siddhesh
next prev parent reply other threads:[~2021-02-12 0:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 5:42 Siddhesh Poyarekar
2021-02-03 9:32 ` Florian Weimer
2021-02-03 13:45 ` Siddhesh Poyarekar
2021-02-03 13:48 ` Florian Weimer
2021-02-03 14:35 ` Siddhesh Poyarekar
2021-02-03 14:37 ` Florian Weimer
2021-02-08 13:42 ` Nix
2021-02-08 14:21 ` Siddhesh Poyarekar
2021-02-08 15:58 ` Nix
2021-02-08 16:02 ` Siddhesh Poyarekar
2021-02-08 19:06 ` Nix
2021-02-11 14:35 ` [PING][PATCH] " Siddhesh Poyarekar
2021-02-11 19:25 ` [PATCH] " Adhemerval Zanella
2021-02-12 0:56 ` Siddhesh Poyarekar [this message]
2021-02-12 2:55 ` Siddhesh Poyarekar
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