x86-64: Fix the dtv field load for x32 [BZ #31184]

On x32, I got

FAIL: elf/tst-tlsgap

$ gdb elf/tst-tlsgap
...
open tst-tlsgap-mod1.so

Thread 2 "tst-tlsgap" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 2268754]
_dl_tlsdesc_dynamic () at ../sysdeps/x86_64/dl-tlsdesc.S:108
108		movq	(%rsi), %rax
(gdb) p/x $rsi
$4 = 0xf7dbf9005655fb18
(gdb)

This is caused by

_dl_tlsdesc_dynamic:
        _CET_ENDBR
        /* Preserve call-clobbered registers that we modify.
           We need two scratch regs anyway.  */
        movq    %rsi, -16(%rsp)
        movq    %fs:DTV_OFFSET, %rsi

Since the dtv field in TCB is a pointer, %fs:DTV_OFFSET is a 32-bit
location, not 64-bit.  Load the dtv field to RSI_LP instead of rsi.
This fixes BZ #31184.

(cherry picked from commit 3502440397bbb840e2f7223734aa5cc2cc0e29b6)

diff --git a/NEWS b/NEWS
index ed72d2f2e6d585edc2aae249325511f8527f8903..377660ece0f879d0b953d2fe66238f85f30f6447 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -87,6 +87,7 @@ The following bugs are resolved with this release:
   [30804] F_GETLK, F_SETLK, and F_SETLKW value change for powerpc64 with
     -D_FILE_OFFSET_BITS=64
   [30842] Stack read overflow in getaddrinfo in no-aaaa mode (CVE-2023-4527)
+  [31184] FAIL: elf/tst-tlsgap
 \f
 Version 2.36
 

diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
index 0db2cb41526a1651982c5e52759426ff1754fe1d..706856e095de6230e48055ff7b2b34cfcb4c63d8 100644 (file)
--- a/sysdeps/x86_64/dl-tlsdesc.S
+++ b/sysdeps/x86_64/dl-tlsdesc.S
@@ -102,7 +102,7 @@ _dl_tlsdesc_dynamic:
        /* Preserve call-clobbered registers that we modify.
           We need two scratch regs anyway.  */
        movq    %rsi, -16(%rsp)
-       movq    %fs:DTV_OFFSET, %rsi
+       mov     %fs:DTV_OFFSET, %RSI_LP
        movq    %rdi, -8(%rsp)
        movq    TLSDESC_ARG(%rax), %rdi
        movq    (%rsi), %rax