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| author | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2021-07-22 18:37:59 +0530 |
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| committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2021-07-22 18:37:59 +0530 |
| commit | 2d2d9f2b48a943fa556301db532103d09800da4d (patch) | |
| tree | 1adb6efbb63ebadd37233851cf14e5cf394de59f /manual/tunables.texi | |
| parent | 55a4dd39308951da4b0da84b19e415c2bb451b60 (diff) | |
| download | glibc-2d2d9f2b48a943fa556301db532103d09800da4d.zip glibc-2d2d9f2b48a943fa556301db532103d09800da4d.tar.gz glibc-2d2d9f2b48a943fa556301db532103d09800da4d.tar.bz2 | |
Move malloc hooks into a compat DSO
Remove all malloc hook uses from core malloc functions and move it
into a new library libc_malloc_debug.so. With this, the hooks now no
longer have any effect on the core library.
libc_malloc_debug.so is a malloc interposer that needs to be preloaded
to get hooks functionality back so that the debugging features that
depend on the hooks, i.e. malloc-check, mcheck and mtrace work again.
Without the preloaded DSO these debugging features will be nops.
These features will be ported away from hooks in subsequent patches.
Similarly, legacy applications that need hooks functionality need to
preload libc_malloc_debug.so.
The symbols exported by libc_malloc_debug.so are maintained at exactly
the same version as libc.so.
Finally, static binaries will no longer be able to use malloc
debugging features since they cannot preload the debugging DSO.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'manual/tunables.texi')
| -rw-r--r-- | manual/tunables.texi | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/manual/tunables.texi b/manual/tunables.texi index ebdb562..e264e91 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -113,7 +113,9 @@ following tunables in the @code{malloc} namespace: @deftp Tunable glibc.malloc.check This tunable supersedes the @env{MALLOC_CHECK_} environment variable and is -identical in features. +identical in features. This tunable has no effect by default and needs the +debug library @file{libc_malloc_debug.so} to be preloaded using the +@code{LD_PRELOAD} environment variable. Setting this tunable to a non-zero value less than 4 enables a special (less efficient) memory allocator for the @code{malloc} family of functions that is |