| Message ID | 874jebdorl.fsf@oldenburg.str.redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] Linux: Switch back to assembly syscall wrapper for prctl (bug 29770) | expand |
Hi Florian, On mer. 14 févr. 2024 16:55:10, Florian Weimer wrote: > 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. > > --- > v3: Commit message updated. > > sysdeps/unix/sysv/linux/syscalls.list | 1 + > sysdeps/unix/sysv/linux/{ => x86_64/x32}/prctl.c | 5 +---- > 2 files changed, 2 insertions(+), 4 deletions(-) LGTM, the extra info in the commit logs are much appreciated :) Reviewed-By: Simon Chopin <simon.chopin@canonical.com> > > 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 > > base-commit: 491e55beab7457ed310a4a47496f4a333c5d1032 >
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
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. --- v3: Commit message updated. sysdeps/unix/sysv/linux/syscalls.list | 1 + sysdeps/unix/sysv/linux/{ => x86_64/x32}/prctl.c | 5 +---- 2 files changed, 2 insertions(+), 4 deletions(-) base-commit: 491e55beab7457ed310a4a47496f4a333c5d1032