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| author | Alexandre Oliva <aoliva@redhat.com> | 2017-02-03 20:35:16 -0500 |
|---|---|---|
| committer | Carlos O'Donell <carlos@systemhalted.org> | 2017-02-03 21:34:14 -0500 |
| commit | d675eaf7d99096a952c1d140abfed82c939fb259 (patch) | |
| tree | aa4d46c8e5d704b3a8dfa8b38765e2710adccff2 | |
| parent | 33d7e138ca63b4091bba840c609a95cdcc56c10e (diff) | |
| download | glibc-d675eaf7d99096a952c1d140abfed82c939fb259.tar.gz glibc-d675eaf7d99096a952c1d140abfed82c939fb259.tar.xz glibc-d675eaf7d99096a952c1d140abfed82c939fb259.zip | |
Bug 20915: Do not initialize DTV of other threads.
In _dl_nothread_init_static_tls() and init_one_static_tls() we must not touch the DTV of other threads since we do not have ownership of them. The DTV need not be initialized at this point anyway since only LD/GD accesses will use them. If LD/GD accesses occur they will take care to initialize their own thread's DTV. Concurrency comments were removed from the patch since they need to be reworked along with a full description of DTV ownership and when it is or is not safe to modify these structures. Alexandre Oliva's original patch and discussion: https://sourceware.org/ml/libc-alpha/2016-09/msg00512.html
| -rw-r--r-- | ChangeLog | 9 | ||||
| -rw-r--r-- | elf/dl-reloc.c | 6 | ||||
| -rw-r--r-- | nptl/allocatestack.c | 5 |
3 files changed, 9 insertions, 11 deletions
diff --git a/ChangeLog b/ChangeLog index f70871d4ec..9ed7ff6883 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2017-02-03 Alexandre Oliva <aoliva@redhat.com> + Florian Weimer <fweimer@redhat.com> + Carlos O'Donell <carlos@redhat.com> + + [BZ #20915] + * elf/dl-reloc.c (_dl_nothread_init_static_tls): + Do not initialize DTV. + * nptl/allocatestack.c (init_one_static_tls): Likewise. + 2017-02-03 David S. Miller <davem@davemloft.net> * sysdeps/sparc/sparc64/fpu/multiarch/s_fmax-vis3.S: Remove file. diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c index 52311f0278..4ac558df52 100644 --- a/elf/dl-reloc.c +++ b/elf/dl-reloc.c @@ -137,12 +137,6 @@ _dl_nothread_init_static_tls (struct link_map *map) # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" #endif - /* Fill in the DTV slot so that a later LD/GD access will find it. */ - dtv_t *dtv = THREAD_DTV (); - assert (map->l_tls_modid <= dtv[-1].counter); - dtv[map->l_tls_modid].pointer.to_free = NULL; - dtv[map->l_tls_modid].pointer.val = dest; - /* Initialize the memory. */ memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size), '\0', map->l_tls_blocksize - map->l_tls_initimage_size); diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 6402ea43f2..8a228ab254 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -1191,11 +1191,6 @@ init_one_static_tls (struct pthread *curp, struct link_map *map) # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" # endif - /* Fill in the DTV slot so that a later LD/GD access will find it. */ - dtv_t *dtv = GET_DTV (TLS_TPADJ (curp)); - dtv[map->l_tls_modid].pointer.to_free = NULL; - dtv[map->l_tls_modid].pointer.val = dest; - /* Initialize the memory. */ memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size), '\0', map->l_tls_blocksize - map->l_tls_initimage_size); |