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-rw-r--r--meta/recipes-core/eglibc/eglibc-2.19/0001-R_ARM_TLS_DTPOFF32.patch56
1 files changed, 56 insertions, 0 deletions
diff --git a/meta/recipes-core/eglibc/eglibc-2.19/0001-R_ARM_TLS_DTPOFF32.patch b/meta/recipes-core/eglibc/eglibc-2.19/0001-R_ARM_TLS_DTPOFF32.patch
new file mode 100644
index 0000000000..b4489e9ae9
--- /dev/null
+++ b/meta/recipes-core/eglibc/eglibc-2.19/0001-R_ARM_TLS_DTPOFF32.patch
@@ -0,0 +1,56 @@
+
+Quote from bug 1443 which explains what the patch does :
+
+ We build some random program and link it with -lust. When we run it,
+ it dies with a SIGSEGV before reaching main().
+
+ Libust.so depends on liburcu-bp.so from the usermode-rcu package.
+ Although libust.so is not prelinked, liburcu-bp.so IS prelinked; this
+ is critical.
+
+ Libust.so uses a TLS / __thread variable that is defined in liburcu-
+ bp.so. There are special ARM-specific relocation types that allow two
+ shared libraries to share thread-specific data. This is critical too.
+
+ One more critical issue: although liburcu-bp.so is prelinked, we can't
+ load it at its prelinked address, because we also link against
+ librt.so, and librt.so uses that address.
+
+ The dynamic linker is forced to relink liburcu-bp.so at a different
+ address. In the course of relinking, it processes the special ARM
+ relocation record mentioned above. The prelinker has already filled
+ in the information, which is a short offset into a table of thread-
+ specific data that is allocated per-thread for each library that uses
+ TLS. Because the normal behavior of a relocation is to add the symbol
+ value to an addend stored at the address being relocated, we end up
+ adding the short offset to itself, doubling it.
+
+ Now we have an awkward situation. The libust.so library doesn't know
+ about the addend, so its TLS data for this element is correct. The
+ liburcu-bp.so library has a different offset for the element. When we
+ go to initialize the element for the first time in liburcu-bp.so, we
+ write the address of the result at the doubled (broken) offset.
+ Later, when we refer to the address from libust.so, we check the value
+ at the correct offset, but it's NULL, so we eat hot SIGSEGV.
+
+Upstream-Status: Pending
+
+Signed-off-by: Andrei Dinu <andrei.adrianx.dinu@intel.com>
+---
+ .../libc/ports/sysdeps/arm/dl-machine.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+ndex 8d905e8..dcfa71e 100644
+--- libc.orig/ports/sysdeps/arm/dl-machine.h
++++ libc/ports/sysdeps/arm/dl-machine.h
+@@ -503,7 +503,7 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
+
+ case R_ARM_TLS_DTPOFF32:
+ if (sym != NULL)
+- *reloc_addr += sym->st_value;
++ *reloc_addr = sym->st_value;
+ break;
+
+ case R_ARM_TLS_TPOFF32:
+--
+