| Message ID | 026514e3fd5f4c357c00542c2730f1fe62436b9d.1722547712.git.fweimer@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | elf: Avoid re-initializing already allocated TLS in dlopen (bug 31717) | expand |
On 8/1/24 5:31 PM, Florian Weimer wrote: > Also remove an outdated comment: _dl_allocate_tls_init is > called as part of pthread_create. LGTM. Reviewed-by: Carlos O'Donell <carlos@redhat.com> > --- > elf/dl-tls.c | 13 +++++++++---- > elf/rtld.c | 2 +- > nptl/allocatestack.c | 2 +- > sysdeps/generic/ldsodefs.h | 4 +--- > 4 files changed, 12 insertions(+), 9 deletions(-) > > diff --git a/elf/dl-tls.c b/elf/dl-tls.c > index 3d221273f1..ecb966d282 100644 > --- a/elf/dl-tls.c > +++ b/elf/dl-tls.c > @@ -552,9 +552,14 @@ _dl_resize_dtv (dtv_t *dtv, size_t max_modid) > /* Allocate initial TLS. RESULT should be a non-NULL pointer to storage > for the TLS space. The DTV may be resized, and so this function may > call malloc to allocate that space. The loader's GL(dl_load_tls_lock) > - is taken when manipulating global TLS-related data in the loader. */ > + is taken when manipulating global TLS-related data in the loader. > + > + If MAIN_THREAD, this is the first call during process > + initialization. In this case, TLS initialization for secondary > + (audit) namespaces is skipped because that has already been handled > + by dlopen. */ > void * > -_dl_allocate_tls_init (void *result, bool init_tls) > +_dl_allocate_tls_init (void *result, bool main_thread) > { > if (result == NULL) > /* The memory allocation failed. */ > @@ -633,7 +638,7 @@ _dl_allocate_tls_init (void *result, bool init_tls) > because it would already be set by the audit setup. However, > subsequent thread creation would need to follow the default > behaviour. */ > - if (map->l_ns != LM_ID_BASE && !init_tls) > + if (map->l_ns != LM_ID_BASE && main_thread) > continue; > memset (__mempcpy (dest, map->l_tls_initimage, > map->l_tls_initimage_size), '\0', > @@ -661,7 +666,7 @@ _dl_allocate_tls (void *mem) > { > return _dl_allocate_tls_init (mem == NULL > ? _dl_allocate_tls_storage () > - : allocate_dtv (mem), true); > + : allocate_dtv (mem), false); > } > rtld_hidden_def (_dl_allocate_tls) > > diff --git a/elf/rtld.c b/elf/rtld.c > index bfdf632e77..09b9c9993b 100644 > --- a/elf/rtld.c > +++ b/elf/rtld.c > @@ -2338,7 +2338,7 @@ dl_main (const ElfW(Phdr) *phdr, > into the main thread's TLS area, which we allocated above. > Note: thread-local variables must only be accessed after completing > the next step. */ > - _dl_allocate_tls_init (tcbp, false); > + _dl_allocate_tls_init (tcbp, true); > > /* And finally install it for the main thread. */ > if (! __rtld_tls_init_tp_called) > diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c > index f35a8369bd..2cb562f8ea 100644 > --- a/nptl/allocatestack.c > +++ b/nptl/allocatestack.c > @@ -139,7 +139,7 @@ get_cached_stack (size_t *sizep, void **memp) > memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t)); > > /* Re-initialize the TLS. */ > - _dl_allocate_tls_init (TLS_TPADJ (result), true); > + _dl_allocate_tls_init (TLS_TPADJ (result), false); > > return result; > } > diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h > index 656e8a3fa0..154efb0e19 100644 > --- a/sysdeps/generic/ldsodefs.h > +++ b/sysdeps/generic/ldsodefs.h > @@ -1200,10 +1200,8 @@ extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp); > > extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden; > > -/* These are internal entry points to the two halves of _dl_allocate_tls, > - only used within rtld.c itself at startup time. */ > extern void *_dl_allocate_tls_storage (void) attribute_hidden; > -extern void *_dl_allocate_tls_init (void *, bool); > +extern void *_dl_allocate_tls_init (void *result, bool main_thread); > rtld_hidden_proto (_dl_allocate_tls_init) > > /* True if the TCB has been set up. */
diff --git a/elf/dl-tls.c b/elf/dl-tls.c index 3d221273f1..ecb966d282 100644 --- a/elf/dl-tls.c +++ b/elf/dl-tls.c @@ -552,9 +552,14 @@ _dl_resize_dtv (dtv_t *dtv, size_t max_modid) /* Allocate initial TLS. RESULT should be a non-NULL pointer to storage for the TLS space. The DTV may be resized, and so this function may call malloc to allocate that space. The loader's GL(dl_load_tls_lock) - is taken when manipulating global TLS-related data in the loader. */ + is taken when manipulating global TLS-related data in the loader. + + If MAIN_THREAD, this is the first call during process + initialization. In this case, TLS initialization for secondary + (audit) namespaces is skipped because that has already been handled + by dlopen. */ void * -_dl_allocate_tls_init (void *result, bool init_tls) +_dl_allocate_tls_init (void *result, bool main_thread) { if (result == NULL) /* The memory allocation failed. */ @@ -633,7 +638,7 @@ _dl_allocate_tls_init (void *result, bool init_tls) because it would already be set by the audit setup. However, subsequent thread creation would need to follow the default behaviour. */ - if (map->l_ns != LM_ID_BASE && !init_tls) + if (map->l_ns != LM_ID_BASE && main_thread) continue; memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size), '\0', @@ -661,7 +666,7 @@ _dl_allocate_tls (void *mem) { return _dl_allocate_tls_init (mem == NULL ? _dl_allocate_tls_storage () - : allocate_dtv (mem), true); + : allocate_dtv (mem), false); } rtld_hidden_def (_dl_allocate_tls) diff --git a/elf/rtld.c b/elf/rtld.c index bfdf632e77..09b9c9993b 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2338,7 +2338,7 @@ dl_main (const ElfW(Phdr) *phdr, into the main thread's TLS area, which we allocated above. Note: thread-local variables must only be accessed after completing the next step. */ - _dl_allocate_tls_init (tcbp, false); + _dl_allocate_tls_init (tcbp, true); /* And finally install it for the main thread. */ if (! __rtld_tls_init_tp_called) diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index f35a8369bd..2cb562f8ea 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -139,7 +139,7 @@ get_cached_stack (size_t *sizep, void **memp) memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t)); /* Re-initialize the TLS. */ - _dl_allocate_tls_init (TLS_TPADJ (result), true); + _dl_allocate_tls_init (TLS_TPADJ (result), false); return result; } diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 656e8a3fa0..154efb0e19 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -1200,10 +1200,8 @@ extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp); extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden; -/* These are internal entry points to the two halves of _dl_allocate_tls, - only used within rtld.c itself at startup time. */ extern void *_dl_allocate_tls_storage (void) attribute_hidden; -extern void *_dl_allocate_tls_init (void *, bool); +extern void *_dl_allocate_tls_init (void *result, bool main_thread); rtld_hidden_proto (_dl_allocate_tls_init) /* True if the TCB has been set up. */