Re: [PATCH 3/3] vdso: preallocate new vmas

[Richard Weinberger <richard@nod.at>]

Am 18.10.2013 02:50, schrieb Davidlohr Bueso:
> With the exception of um and tile, architectures that use
> the install_special_mapping() function, when setting up a
> new vma at program startup, do so with the mmap_sem lock
> held for writing. Unless there's an error, this process
> ends up allocating a new vma through kmem_cache_zalloc,
> and inserting it in the task's address space.
> 
> This patch moves the vma's space allocation outside of
> install_special_mapping(), and leaves the callers to do so 
> explicitly, without depending on mmap_sem. The same goes for 
> freeing: if the new vma isn't used (and thus the process fails 
> at some point), it's caller's responsibility to free it - 
> currently this is done inside install_special_mapping.
> 
> Furthermore, uprobes behaves exactly the same and thus now the
> xol_add_vma() function also preallocates the new vma.
> 
> While the changes to x86 vdso handling have been tested on both
> large and small 64-bit systems, the rest of the architectures
> are totally *untested*. Note that all changes are quite similar
> from architecture to architecture.
> 
> This patch, when tested on a 64core, 256 Gb NUMA server, benefited
> several aim7 workloads: long +27% throughput with over 1500 users;
> compute +6.5% with over 1000 users; fserver +83% for small amounts
> of users (10-100 range) and +9% for more and new_fserver, showing
> a similar behavior, got +67% boost with 100 users and an avg of +8%
> when more users were added.
> 
> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Richard Kuo <rkuo@codeaurora.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> Cc: Jeff Dike <jdike@addtoit.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
>  arch/arm/kernel/process.c          | 22 ++++++++++++++++------
>  arch/arm64/kernel/vdso.c           | 21 +++++++++++++++++----
>  arch/hexagon/kernel/vdso.c         | 16 ++++++++++++----
>  arch/mips/kernel/vdso.c            | 10 +++++++++-
>  arch/powerpc/kernel/vdso.c         | 11 ++++++++---
>  arch/s390/kernel/vdso.c            | 19 +++++++++++++++----
>  arch/sh/kernel/vsyscall/vsyscall.c | 11 ++++++++++-
>  arch/tile/kernel/vdso.c            | 13 ++++++++++---
>  arch/um/kernel/skas/mmu.c          | 16 +++++++++++-----
>  arch/unicore32/kernel/process.c    | 17 ++++++++++++-----
>  arch/x86/um/vdso/vma.c             | 18 ++++++++++++++----
>  arch/x86/vdso/vdso32-setup.c       | 16 +++++++++++++++-
>  arch/x86/vdso/vma.c                | 10 +++++++++-
>  include/linux/mm.h                 |  3 ++-
>  kernel/events/uprobes.c            | 14 ++++++++++++--
>  mm/mmap.c                          | 18 +++++++-----------
>  16 files changed, 179 insertions(+), 56 deletions(-)
> 
> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> index 94f6b05..5637c92 100644
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -13,6 +13,7 @@
>  #include <linux/export.h>
>  #include <linux/sched.h>
>  #include <linux/kernel.h>
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/stddef.h>
>  #include <linux/unistd.h>
> @@ -480,6 +481,7 @@ extern struct page *get_signal_page(void);
>  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
>  	unsigned long addr;
>  	int ret;
>  
> @@ -488,6 +490,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	if (!signal_page)
>  		return -ENOMEM;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
>  	if (IS_ERR_VALUE(addr)) {
> @@ -496,14 +502,18 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	}
>  
>  	ret = install_special_mapping(mm, addr, PAGE_SIZE,
> -		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
> -		&signal_page);
> -
> -	if (ret == 0)
> -		mm->context.sigpage = addr;
> +				      VM_READ | VM_EXEC | VM_MAYREAD |
> +				      VM_MAYWRITE | VM_MAYEXEC,
> +				      &signal_page, &vma);
> +	if (ret)
> +		goto up_fail;
>  
> - up_fail:
> +	mm->context.sigpage = addr;
> +	up_write(&mm->mmap_sem);
> +	return 0;
> +up_fail:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  #endif
> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> index 6a389dc..519a44c 100644
> --- a/arch/arm64/kernel/vdso.c
> +++ b/arch/arm64/kernel/vdso.c
> @@ -83,20 +83,26 @@ arch_initcall(alloc_vectors_page);
>  
>  int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
>  {
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  	unsigned long addr = AARCH32_VECTORS_BASE;
>  	int ret;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  	current->mm->context.vdso = (void *)addr;
>  
>  	/* Map vectors page at the high address. */
>  	ret = install_special_mapping(mm, addr, PAGE_SIZE,
>  				      VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
> -				      vectors_page);
> +				      vectors_page, &vma);
>  
>  	up_write(&mm->mmap_sem);
> -
> +	if (ret)
> +		kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  #endif /* CONFIG_COMPAT */
> @@ -152,10 +158,15 @@ arch_initcall(vdso_init);
>  int arch_setup_additional_pages(struct linux_binprm *bprm,
>  				int uses_interp)
>  {
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  	unsigned long vdso_base, vdso_mapping_len;
>  	int ret;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	/* Be sure to map the data page */
>  	vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;
>  
> @@ -170,15 +181,17 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
>  	ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
>  				      VM_READ|VM_EXEC|
>  				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				      vdso_pagelist);
> +				      vdso_pagelist, &vma);
>  	if (ret) {
>  		mm->context.vdso = NULL;
>  		goto up_fail;
>  	}
>  
> +	up_write(&mm->mmap_sem);
> +	return ret;
>  up_fail:
>  	up_write(&mm->mmap_sem);
> -
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/arch/hexagon/kernel/vdso.c b/arch/hexagon/kernel/vdso.c
> index 0bf5a87..188c5bd 100644
> --- a/arch/hexagon/kernel/vdso.c
> +++ b/arch/hexagon/kernel/vdso.c
> @@ -19,6 +19,7 @@
>   */
>  
>  #include <linux/err.h>
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/vmalloc.h>
>  #include <linux/binfmts.h>
> @@ -63,8 +64,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	int ret;
>  	unsigned long vdso_base;
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  
>  	/* Try to get it loaded right near ld.so/glibc. */
> @@ -78,17 +84,19 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  
>  	/* MAYWRITE to allow gdb to COW and set breakpoints. */
>  	ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
> -				      VM_READ|VM_EXEC|
> -				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				      &vdso_page);
> -
> +					      VM_READ|VM_EXEC|
> +					      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> +					      &vdso_page, &vma);
>  	if (ret)
>  		goto up_fail;
>  
>  	mm->context.vdso = (void *)vdso_base;
>  
> +	up_write(&mm->mmap_sem);
> +	return 0;
>  up_fail:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
> index 0f1af58..cfc2c7b 100644
> --- a/arch/mips/kernel/vdso.c
> +++ b/arch/mips/kernel/vdso.c
> @@ -74,8 +74,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	int ret;
>  	unsigned long addr;
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  
>  	addr = vdso_addr(mm->start_stack);
> @@ -89,15 +94,18 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	ret = install_special_mapping(mm, addr, PAGE_SIZE,
>  				      VM_READ|VM_EXEC|
>  				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				      &vdso_page);
> +				      &vdso_page, &vma);
>  
>  	if (ret)
>  		goto up_fail;
>  
>  	mm->context.vdso = (void *)addr;
>  
> +	up_write(&mm->mmap_sem);
> +	return 0;
>  up_fail:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
> index 1d9c926..a23fb5f 100644
> --- a/arch/powerpc/kernel/vdso.c
> +++ b/arch/powerpc/kernel/vdso.c
> @@ -193,6 +193,7 @@ static void dump_vdso_pages(struct vm_area_struct * vma)
>  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
>  	struct page **vdso_pagelist;
>  	unsigned long vdso_pages;
>  	unsigned long vdso_base;
> @@ -232,6 +233,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	/* Add a page to the vdso size for the data page */
>  	vdso_pages ++;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	/*
>  	 * pick a base address for the vDSO in process space. We try to put it
>  	 * at vdso_base which is the "natural" base for it, but we might fail
> @@ -271,7 +276,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
>  				     VM_READ|VM_EXEC|
>  				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				     vdso_pagelist);
> +				     vdso_pagelist, &vma);
>  	if (rc) {
>  		current->mm->context.vdso_base = 0;
>  		goto fail_mmapsem;
> @@ -279,9 +284,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  
>  	up_write(&mm->mmap_sem);
>  	return 0;
> -
> - fail_mmapsem:
> +fail_mmapsem:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return rc;
>  }
>  
> diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
> index 05d75c4..4e00e11 100644
> --- a/arch/s390/kernel/vdso.c
> +++ b/arch/s390/kernel/vdso.c
> @@ -180,6 +180,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	struct mm_struct *mm = current->mm;
>  	struct page **vdso_pagelist;
> +	struct vm_area_struct *vma;
>  	unsigned long vdso_pages;
>  	unsigned long vdso_base;
>  	int rc;
> @@ -213,6 +214,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	if (vdso_pages == 0)
>  		return 0;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	current->mm->context.vdso_base = 0;
>  
>  	/*
> @@ -224,7 +229,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	vdso_base = get_unmapped_area(NULL, 0, vdso_pages << PAGE_SHIFT, 0, 0);
>  	if (IS_ERR_VALUE(vdso_base)) {
>  		rc = vdso_base;
> -		goto out_up;
> +		goto out_err;
>  	}
>  
>  	/*
> @@ -247,11 +252,17 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
>  				     VM_READ|VM_EXEC|
>  				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				     vdso_pagelist);
> -	if (rc)
> +				     vdso_pagelist, &vma);
> +	if (rc) {
>  		current->mm->context.vdso_base = 0;
> -out_up:
> +		goto out_err;
> +	}
> +
> +	up_write(&mm->mmap_sem);
> +	return 0;
> +out_err:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return rc;
>  }
>  
> diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
> index 5ca5797..49d3834 100644
> --- a/arch/sh/kernel/vsyscall/vsyscall.c
> +++ b/arch/sh/kernel/vsyscall/vsyscall.c
> @@ -10,6 +10,7 @@
>   * License.  See the file "COPYING" in the main directory of this archive
>   * for more details.
>   */
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/kernel.h>
>  #include <linux/init.h>
> @@ -61,9 +62,14 @@ int __init vsyscall_init(void)
>  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
>  	unsigned long addr;
>  	int ret;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
>  	if (IS_ERR_VALUE(addr)) {
> @@ -74,14 +80,17 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	ret = install_special_mapping(mm, addr, PAGE_SIZE,
>  				      VM_READ | VM_EXEC |
>  				      VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
> -				      syscall_pages);
> +				      syscall_pages, &vma);
>  	if (unlikely(ret))
>  		goto up_fail;
>  
>  	current->mm->context.vdso = (void *)addr;
>  
> +	up_write(&mm->mmap_sem);
> +	return 0;
>  up_fail:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/arch/tile/kernel/vdso.c b/arch/tile/kernel/vdso.c
> index 1533af2..cf93e62 100644
> --- a/arch/tile/kernel/vdso.c
> +++ b/arch/tile/kernel/vdso.c
> @@ -15,6 +15,7 @@
>  #include <linux/binfmts.h>
>  #include <linux/compat.h>
>  #include <linux/elf.h>
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/pagemap.h>
>  
> @@ -140,6 +141,7 @@ int setup_vdso_pages(void)
>  {
>  	struct page **pagelist;
>  	unsigned long pages;
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  	unsigned long vdso_base = 0;
>  	int retval = 0;
> @@ -147,6 +149,10 @@ int setup_vdso_pages(void)
>  	if (!vdso_ready)
>  		return 0;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	mm->context.vdso_base = 0;
>  
>  	pagelist = vdso_pagelist;
> @@ -198,10 +204,11 @@ int setup_vdso_pages(void)
>  					 pages << PAGE_SHIFT,
>  					 VM_READ|VM_EXEC |
>  					 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
> -					 pagelist);
> -	if (retval)
> +					 pagelist, &vma);
> +	if (retval) {
>  		mm->context.vdso_base = 0;
> -
> +		kmem_cache_free(vm_area_cachep, vma);
> +	}
>  	return retval;
>  }
>  
> diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
> index 007d550..a6c3190 100644
> --- a/arch/um/kernel/skas/mmu.c
> +++ b/arch/um/kernel/skas/mmu.c
> @@ -104,18 +104,23 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
>  void uml_setup_stubs(struct mm_struct *mm)
>  {
>  	int err, ret;
> +	struct vm_area_struct *vma;
>  
>  	if (!skas_needs_stub)
>  		return;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;

This function has return type void.
Use goto err please.

> +
>  	ret = init_stub_pte(mm, STUB_CODE,
>  			    (unsigned long) &__syscall_stub_start);
>  	if (ret)
> -		goto out;
> +		goto err;
>  
>  	ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack);
>  	if (ret)
> -		goto out;
> +		goto err;
>  
>  	mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
>  	mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
> @@ -124,14 +129,15 @@ void uml_setup_stubs(struct mm_struct *mm)
>  	err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
>  				      VM_READ | VM_MAYREAD | VM_EXEC |
>  				      VM_MAYEXEC | VM_DONTCOPY | VM_PFNMAP,
> -				      mm->context.stub_pages);
> +				      mm->context.stub_pages, &vma);
>  	if (err) {
>  		printk(KERN_ERR "install_special_mapping returned %d\n", err);
> -		goto out;
> +		goto err;
>  	}
>  	return;
>  
> -out:
> +err:
> +	kmem_cache_free(vm_area_cachep, vma);
>  	force_sigsegv(SIGSEGV, current);
>  }
>  
> diff --git a/arch/unicore32/kernel/process.c b/arch/unicore32/kernel/process.c
> index 778ebba..c18b0e4 100644
> --- a/arch/unicore32/kernel/process.c
> +++ b/arch/unicore32/kernel/process.c
> @@ -14,6 +14,7 @@
>  #include <linux/module.h>
>  #include <linux/sched.h>
>  #include <linux/kernel.h>
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/stddef.h>
>  #include <linux/unistd.h>
> @@ -313,12 +314,18 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
>  
>  int vectors_user_mapping(void)
>  {
> +	int ret = 0;
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
> -	return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
> -				       VM_READ | VM_EXEC |
> -				       VM_MAYREAD | VM_MAYEXEC |
> -				       VM_DONTEXPAND | VM_DONTDUMP,
> -				       NULL);
> +
> +	ret = install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
> +				      VM_READ | VM_EXEC |
> +				      VM_MAYREAD | VM_MAYEXEC |
> +				      VM_DONTEXPAND | VM_DONTDUMP,
> +				      NULL, &vma);
> +	if (ret)
> +		kmem_cache_free(vm_area_cachep, vma);
> +	return ret;
>  }
>  
>  const char *arch_vma_name(struct vm_area_struct *vma)
> diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
> index af91901..888d856 100644
> --- a/arch/x86/um/vdso/vma.c
> +++ b/arch/x86/um/vdso/vma.c
> @@ -55,19 +55,29 @@ subsys_initcall(init_vdso);
>  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	int err;
> +	struct vm_area_struct *vma;
>  	struct mm_struct *mm = current->mm;
>  
>  	if (!vdso_enabled)
>  		return 0;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  
>  	err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
> -		VM_READ|VM_EXEC|
> -		VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -		vdsop);
> +				      VM_READ|VM_EXEC|
> +				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> +				      vdsop, &vma);
> +	if (err)
> +		goto out_err;
>  
>  	up_write(&mm->mmap_sem);
> -
> +	return err;
> +out_err:
> +	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return err;
>  }
> diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
> index d6bfb87..debb339 100644
> --- a/arch/x86/vdso/vdso32-setup.c
> +++ b/arch/x86/vdso/vdso32-setup.c
> @@ -13,6 +13,7 @@
>  #include <linux/gfp.h>
>  #include <linux/string.h>
>  #include <linux/elf.h>
> +#include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/err.h>
>  #include <linux/module.h>
> @@ -307,6 +308,7 @@ int __init sysenter_setup(void)
>  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
>  	unsigned long addr;
>  	int ret = 0;
>  	bool compat;
> @@ -319,6 +321,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	if (vdso_enabled == VDSO_DISABLED)
>  		return 0;
>  
> +	if (compat_uses_vma || !compat) {
> +		vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +		if (unlikely(!vma))
> +			return -ENOMEM;
> +	}
> +
>  	down_write(&mm->mmap_sem);
>  
>  	/* Test compat mode once here, in case someone
> @@ -346,7 +354,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  		ret = install_special_mapping(mm, addr, PAGE_SIZE,
>  					      VM_READ|VM_EXEC|
>  					      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -					      vdso32_pages);
> +					      vdso32_pages, &vma);
>  
>  		if (ret)
>  			goto up_fail;
> @@ -355,12 +363,18 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>  	current_thread_info()->sysenter_return =
>  		VDSO32_SYMBOL(addr, SYSENTER_RETURN);
>  
> +	up_write(&mm->mmap_sem);
> +
> +	return ret;
> +
>    up_fail:
>  	if (ret)
>  		current->mm->context.vdso = NULL;
>  
>  	up_write(&mm->mmap_sem);
>  
> +	if (ret && (compat_uses_vma || !compat))
> +		kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
> index 431e875..82c6b87 100644
> --- a/arch/x86/vdso/vma.c
> +++ b/arch/x86/vdso/vma.c
> @@ -154,12 +154,17 @@ static int setup_additional_pages(struct linux_binprm *bprm,
>  				  unsigned size)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
>  	unsigned long addr;
>  	int ret;
>  
>  	if (!vdso_enabled)
>  		return 0;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  	addr = vdso_addr(mm->start_stack, size);
>  	addr = get_unmapped_area(NULL, addr, size, 0, 0);
> @@ -173,14 +178,17 @@ static int setup_additional_pages(struct linux_binprm *bprm,
>  	ret = install_special_mapping(mm, addr, size,
>  				      VM_READ|VM_EXEC|
>  				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
> -				      pages);
> +				      pages, &vma);
>  	if (ret) {
>  		current->mm->context.vdso = NULL;
>  		goto up_fail;
>  	}
>  
> +	up_write(&mm->mmap_sem);
> +	return ret;
>  up_fail:
>  	up_write(&mm->mmap_sem);
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 8b6e55e..4984fff 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1515,7 +1515,8 @@ extern struct file *get_mm_exe_file(struct mm_struct *mm);
>  extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
>  extern int install_special_mapping(struct mm_struct *mm,
>  				   unsigned long addr, unsigned long len,
> -				   unsigned long flags, struct page **pages);
> +				   unsigned long flags, struct page **pages,
> +				   struct vm_area_struct **vma_prealloc);
>  
>  extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
>  
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index ad8e1bd..18abeaa 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1099,8 +1099,14 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
>  static int xol_add_vma(struct xol_area *area)
>  {
>  	struct mm_struct *mm = current->mm;
> +	struct vm_area_struct *vma;
> +
>  	int ret = -EALREADY;
>  
> +	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> +	if (unlikely(!vma))
> +		return -ENOMEM;
> +
>  	down_write(&mm->mmap_sem);
>  	if (mm->uprobes_state.xol_area)
>  		goto fail;
> @@ -1114,16 +1120,20 @@ static int xol_add_vma(struct xol_area *area)
>  	}
>  
>  	ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE,
> -				VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page);
> +				      VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO,
> +				      &area->page, &vma);
>  	if (ret)
>  		goto fail;
>  
>  	smp_wmb();	/* pairs with get_xol_area() */
>  	mm->uprobes_state.xol_area = area;
>  	ret = 0;
> +
> +	up_write(&mm->mmap_sem);
> +	return 0;
>   fail:
>  	up_write(&mm->mmap_sem);
> -
> +	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 6a7824d..6e238a3 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2909,17 +2909,17 @@ static const struct vm_operations_struct special_mapping_vmops = {
>   * The region past the last page supplied will always produce SIGBUS.
>   * The array pointer and the pages it points to are assumed to stay alive
>   * for as long as this mapping might exist.
> + *
> + * The caller has the responsibility of allocating the new vma, and freeing
> + * it if it was unused (when insert_vm_struct() fails).
>   */
>  int install_special_mapping(struct mm_struct *mm,
>  			    unsigned long addr, unsigned long len,
> -			    unsigned long vm_flags, struct page **pages)
> +			    unsigned long vm_flags, struct page **pages,
> +			    struct vm_area_struct **vma_prealloc)
>  {
> -	int ret;
> -	struct vm_area_struct *vma;
> -
> -	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
> -	if (unlikely(vma == NULL))
> -		return -ENOMEM;
> +	int ret = 0;
> +	struct vm_area_struct *vma = *vma_prealloc;
>  
>  	INIT_LIST_HEAD(&vma->anon_vma_chain);
>  	vma->vm_mm = mm;
> @@ -2939,11 +2939,7 @@ int install_special_mapping(struct mm_struct *mm,
>  	mm->total_vm += len >> PAGE_SHIFT;
>  
>  	perf_event_mmap(vma);
> -
> -	return 0;
> -
>  out:
> -	kmem_cache_free(vm_area_cachep, vma);
>  	return ret;
>  }
>  
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>