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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 0000000..b4489e9
--- /dev/null
+++ b/meta/recipes-core/eglibc/eglibc-2.19/0001-R_ARM_TLS_DTPOFF32.patch
@@ -0,0 +1,56 @@
1
2Quote from bug 1443 which explains what the patch does :
3
4 We build some random program and link it with -lust. When we run it,
5 it dies with a SIGSEGV before reaching main().
6
7 Libust.so depends on liburcu-bp.so from the usermode-rcu package.
8 Although libust.so is not prelinked, liburcu-bp.so IS prelinked; this
9 is critical.
10
11 Libust.so uses a TLS / __thread variable that is defined in liburcu-
12 bp.so. There are special ARM-specific relocation types that allow two
13 shared libraries to share thread-specific data. This is critical too.
14
15 One more critical issue: although liburcu-bp.so is prelinked, we can't
16 load it at its prelinked address, because we also link against
17 librt.so, and librt.so uses that address.
18
19 The dynamic linker is forced to relink liburcu-bp.so at a different
20 address. In the course of relinking, it processes the special ARM
21 relocation record mentioned above. The prelinker has already filled
22 in the information, which is a short offset into a table of thread-
23 specific data that is allocated per-thread for each library that uses
24 TLS. Because the normal behavior of a relocation is to add the symbol
25 value to an addend stored at the address being relocated, we end up
26 adding the short offset to itself, doubling it.
27
28 Now we have an awkward situation. The libust.so library doesn't know
29 about the addend, so its TLS data for this element is correct. The
30 liburcu-bp.so library has a different offset for the element. When we
31 go to initialize the element for the first time in liburcu-bp.so, we
32 write the address of the result at the doubled (broken) offset.
33 Later, when we refer to the address from libust.so, we check the value
34 at the correct offset, but it's NULL, so we eat hot SIGSEGV.
35
36Upstream-Status: Pending
37
38Signed-off-by: Andrei Dinu <andrei.adrianx.dinu@intel.com>
39---
40 .../libc/ports/sysdeps/arm/dl-machine.h | 2 +-
41 1 file changed, 1 insertion(+), 1 deletion(-)
42
43ndex 8d905e8..dcfa71e 100644
44--- libc.orig/ports/sysdeps/arm/dl-machine.h
45+++ libc/ports/sysdeps/arm/dl-machine.h
46@@ -503,7 +503,7 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
47
48 case R_ARM_TLS_DTPOFF32:
49 if (sym != NULL)
50- *reloc_addr += sym->st_value;
51+ *reloc_addr = sym->st_value;
52 break;
53
54 case R_ARM_TLS_TPOFF32:
55--
56