Re: [Valgrind-users] Timer delete

[Paul F. <pj...@wa...>]

> Yes, the cache disabling is quite hacky, as mentionnd in the doc:
> "Valgrind disables the cache using some internal
>   knowledge of the glibc stack cache implementation and by
>   examining the debug information of the pthread
>   library. This technique is thus somewhat fragile and might
>   not work for all glibc versions. This has been successfully
>   tested with various glibc versions (e.g. 2.11, 2.16, 2.18)
>   on various platforms."
>
>
>
> As you indicate, it looks broken on the more recent glibc version you tried.
>
> Philippe
>
Indeed. Looks like this:


Author: Florian Weimer <fw...@re...>  2021-05-10 10:31:41
Committer: Florian Weimer <fw...@re...>  2021-05-10 10:31:41
Parent: d017b0ab5a181dce4145f3a1b3b27e3341abd201 (elf: Introduce 
__tls_pre_init_tp)
Child:  ee07b3a7222746fafc5d5cb2163c9609b81615ef (nptl: Simplify the 
change_stack_perm calling convention)
Branches: master, remotes/origin/arm/morello/main, 
remotes/origin/arm/morello/v1, remotes/origin/arm/morello/v2, 
remotes/origin/azanella/bz23960-dirent, remotes/origin/azanella/clang, 
remotes/origin/codonell/c-utf8, remotes/origin/codonell/ld-audit, 
remotes/origin/fw/localedef-utf8, remotes/origin/maskray/relr, 
remotes/origin/maskray/x86-mpx, remotes/origin/master, 
remotes/origin/nsz/bug23293, remotes/origin/nsz/bug23293-v5, 
remotes/origin/nsz/bug23293-v6, remotes/origin/release/2.34/master, 
remotes/origin/release/2.35/master, remotes/origin/release/2.36/master, 
remotes/origin/siddhesh/realpath-and-getcwd
Follows: glibc-2.33.9000
Precedes: glibc-2.34

     nptl: Move more stack management variables into _rtld_global

     Permissions of the cached stacks may have to be updated if an object
     is loaded that requires executable stacks, so the dynamic loader
     needs to know about these cached stacks.

     The move of in_flight_stack and stack_cache_actsize is a 
requirement for
     merging __reclaim_stacks into the fork implementation in libc.

     Tested-by: Carlos O'Donell <ca...@re...>
     Reviewed-by: Carlos O'Donell <ca...@re...>

It looks like "stack_cache_actsize" in libc moved to be 
_dl_stack_cache_actsize in ld-linux-x86-64.so.2


A+

Paul