diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2024-08-12 18:26:05 +1000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-01 20:26:13 -0700 |
| commit | edb4a8bffde725db0c9db2b4a508e01f150dba40 (patch) | |
| tree | 9e7f0e8eaadcb4132a4b48c97150d5233db93d93 | |
| parent | 40b88644dd92d99e572063893c2a247598c238d6 (diff) | |
powerpc/vdso: refactor error handling
Linus noticed that the error handling in __arch_setup_additional_pages()
fails to clear the mm VDSO pointer if _install_special_mapping() fails.
In practice there should be no actual bug, because if there's an error the
VDSO pointer is cleared later in arch_setup_additional_pages().
However it's no longer necessary to set the pointer before installing the
mapping. Commit c1bab64360e6 ("powerpc/vdso: Move to
_install_special_mapping() and remove arch_vma_name()") reworked the code
so that the VMA name comes from the vm_special_mapping.name, rather than
relying on arch_vma_name().
So rework the code to only set the VDSO pointer once the mappings have
been installed correctly, and remove the stale comment.
Link: https://lkml.kernel.org/r/20240812082605.743814-4-mpe@ellerman.id.au
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | arch/powerpc/kernel/vdso.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 220a76cae7c1..ee4b9d676cff 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -214,13 +214,6 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int /* Add required alignment. */ vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT); - /* - * Put vDSO base into mm struct. We need to do this before calling - * install_special_mapping or the perf counter mmap tracking code - * will fail to recognise it as a vDSO. - */ - mm->context.vdso = (void __user *)vdso_base + vvar_size; - vma = _install_special_mapping(mm, vdso_base, vvar_size, VM_READ | VM_MAYREAD | VM_IO | VM_DONTDUMP | VM_PFNMAP, &vvar_spec); @@ -240,10 +233,15 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size, VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, vdso_spec); - if (IS_ERR(vma)) + if (IS_ERR(vma)) { do_munmap(mm, vdso_base, vvar_size, NULL); + return PTR_ERR(vma); + } - return PTR_ERR_OR_ZERO(vma); + // Now that the mappings are in place, set the mm VDSO pointer + mm->context.vdso = (void __user *)vdso_base + vvar_size; + + return 0; } int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) @@ -257,8 +255,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) return -EINTR; rc = __arch_setup_additional_pages(bprm, uses_interp); - if (rc) - mm->context.vdso = NULL; mmap_write_unlock(mm); return rc; |