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* [glibc] Linux: Switch back to assembly syscall wrapper for prctl (bug 29770)
@ 2024-02-17 8:17 Florian Weimer
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From: Florian Weimer @ 2024-02-17 8:17 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6a04404521ac4119ae36827eeb288ea84eee7cf6
commit 6a04404521ac4119ae36827eeb288ea84eee7cf6
Author: Florian Weimer <fweimer@redhat.com>
Date: Sat Feb 17 09:17:04 2024 +0100
Linux: Switch back to assembly syscall wrapper for prctl (bug 29770)
Commit ff026950e280bc3e9487b41b460fb31bc5b57721 ("Add a C wrapper for
prctl [BZ #25896]") replaced the assembler wrapper with a C function.
However, on powerpc64le-linux-gnu, the C variadic function
implementation requires extra work in the caller to set up the
parameter save area. Calling a function that needs a parameter save
area without one (because the prototype used indicates the function is
not variadic) corrupts the caller's stack. The Linux manual pages
project documents prctl as a non-variadic function. This has resulted
in various projects over the years using non-variadic prototypes,
including the sanitizer libraries in LLVm and GCC (GCC PR 113728).
This commit switches back to the assembler implementation on most
targets and only keeps the C implementation for x86-64 x32.
Also add the __prctl_time64 alias from commit
b39ffab860cd743a82c91946619f1b8158b0b65e ("Linux: Add time64 alias for
prctl") to sysdeps/unix/sysv/linux/syscalls.list; it was not yet
present in commit ff026950e280bc3e9487b41b460fb31bc5b57721.
This restores the old ABI on powerpc64le-linux-gnu, thus fixing
bug 29770.
Reviewed-By: Simon Chopin <simon.chopin@canonical.com>
Diff:
---
sysdeps/unix/sysv/linux/syscalls.list | 1 +
sysdeps/unix/sysv/linux/{ => x86_64/x32}/prctl.c | 5 +----
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index 73e941ef89..9ac42c3436 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -46,6 +46,7 @@ open_tree EXTRA open_tree i:isU open_tree
pipe2 - pipe2 i:fi __pipe2 pipe2
pidfd_open EXTRA pidfd_open i:iU pidfd_open
pidfd_getfd EXTRA pidfd_getfd i:iiU pidfd_getfd
+prctl EXTRA prctl i:iiiii __prctl prctl __prctl_time64
pivot_root EXTRA pivot_root i:ss pivot_root
pidfd_send_signal EXTRA pidfd_send_signal i:iiPU pidfd_send_signal
process_madvise EXTRA process_madvise i:iPniU process_madvise
diff --git a/sysdeps/unix/sysv/linux/prctl.c b/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c
similarity index 93%
rename from sysdeps/unix/sysv/linux/prctl.c
rename to sysdeps/unix/sysv/linux/x86_64/x32/prctl.c
index 52d234ea0d..4bf1b479a0 100644
--- a/sysdeps/unix/sysv/linux/prctl.c
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c
@@ -1,4 +1,4 @@
-/* prctl - Linux specific syscall.
+/* prctl - Linux specific syscall. x86-64 x32 version.
Copyright (C) 2020-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
@@ -40,6 +40,3 @@ __prctl (int option, ...)
libc_hidden_def (__prctl)
weak_alias (__prctl, prctl)
-#if __TIMESIZE != 64
-weak_alias (__prctl, __prctl_time64)
-#endif
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2024-02-17 8:17 [glibc] Linux: Switch back to assembly syscall wrapper for prctl (bug 29770) Florian Weimer
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