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@xxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Richard Kuo <rkuo@xxxxxxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Paul Mundt <lethal@xxxxxxxxxxxx> Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx> Cc: Jeff Dike <jdike@xxxxxxxxxxx> Cc: Richard Weinberger <richard@xxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> --- 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; + 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; } -- 1.8.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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