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Linux: Switch back to assembly syscall wrapper for prctl (bug 29770)

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Commit ff026950e2 ("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
b39ffab860 ("Linux: Add time64 alias for
prctl") to sysdeps/unix/sysv/linux/syscalls.list; it was not yet
present in commit ff026950e2.

This restores the old ABI on powerpc64le-linux-gnu, thus fixing
bug 29770.

Reviewed-By: Simon Chopin <simon.chopin@canonical.com>
This commit is contained in:
Florian Weimer 2024-02-17 09:17:04 +01:00
parent 0d9166c224
commit 6a04404521
2 changed files with 2 additions and 4 deletions
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1
sysdeps/unix/sysv/linux/syscalls.list
View file

@ -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

5
sysdeps/unix/sysv/linux/prctl.c → sysdeps/unix/sysv/linux/x86_64/x32/prctl.c
View file

@ -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