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From: H.J. Lu <hjl@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc/release/2.34/master] x86-64: Fix the tcb field load for x32 [BZ #31185]
Date: Sat, 23 Dec 2023 17:38:37 +0000 (GMT) [thread overview]
Message-ID: <20231223173838.1EE963858C2D@sourceware.org> (raw)
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2143fcd54025df8ee1e95a31b2cbadcb2e3547ac
commit 2143fcd54025df8ee1e95a31b2cbadcb2e3547ac
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Dec 20 19:42:12 2023 -0800
x86-64: Fix the tcb field load for x32 [BZ #31185]
_dl_tlsdesc_undefweak and _dl_tlsdesc_dynamic access the thread pointer
via the tcb field in TCB:
_dl_tlsdesc_undefweak:
_CET_ENDBR
movq 8(%rax), %rax
subq %fs:0, %rax
ret
_dl_tlsdesc_dynamic:
...
subq %fs:0, %rax
movq -8(%rsp), %rdi
ret
Since the tcb field in TCB is a pointer, %fs:0 is a 32-bit location,
not 64-bit. It should use "sub %fs:0, %RAX_LP" instead. Since
_dl_tlsdesc_undefweak returns ptrdiff_t and _dl_make_tlsdesc_dynamic
returns void *, RAX_LP is appropriate here for x32 and x86-64. This
fixes BZ #31185.
(cherry picked from commit 81be2a61dafc168327c1639e97b6dae128c7ccf3)
Diff:
---
NEWS | 1 +
sysdeps/x86_64/dl-tlsdesc.S | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/NEWS b/NEWS
index ef3a0a4ca7..af73ed99f5 100644
--- a/NEWS
+++ b/NEWS
@@ -161,6 +161,7 @@ The following bugs are resolved with this release:
[30163] posix: Fix system blocks SIGCHLD erroneously
[30305] x86_64: Fix asm constraints in feraiseexcept
[31184] FAIL: elf/tst-tlsgap
+ [31185] Incorrect thread point access in _dl_tlsdesc_undefweak and _dl_tlsdesc_dynamic
\f
Version 2.34
diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
index 18f862f003..37b183a0d8 100644
--- a/sysdeps/x86_64/dl-tlsdesc.S
+++ b/sysdeps/x86_64/dl-tlsdesc.S
@@ -61,7 +61,7 @@ _dl_tlsdesc_return:
_dl_tlsdesc_undefweak:
_CET_ENDBR
movq 8(%rax), %rax
- subq %fs:0, %rax
+ sub %fs:0, %RAX_LP
ret
cfi_endproc
.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
@@ -116,7 +116,7 @@ _dl_tlsdesc_dynamic:
addq TLSDESC_MODOFF(%rdi), %rax
.Lret:
movq -16(%rsp), %rsi
- subq %fs:0, %rax
+ sub %fs:0, %RAX_LP
movq -8(%rsp), %rdi
ret
.Lslow:
reply other threads:[~2023-12-23 17:38 UTC|newest]
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