diff options
| -rw-r--r-- | fs/binfmt_elf.c | 6 | ||||
| -rw-r--r-- | fs/exec.c | 5 | ||||
| -rw-r--r-- | include/linux/mm.h | 10 | ||||
| -rw-r--r-- | mm/memory.c | 2 | ||||
| -rw-r--r-- | mm/mmap.c | 50 | ||||
| -rw-r--r-- | mm/nommu.c | 3 |
6 files changed, 49 insertions, 27 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 1033fbdfdbec..869c3aa0e455 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -320,10 +320,10 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, * Grow the stack manually; some architectures have a limit on how * far ahead a user-space access may be in order to grow the stack. */ - if (mmap_read_lock_killable(mm)) + if (mmap_write_lock_killable(mm)) return -EINTR; - vma = find_extend_vma(mm, bprm->p); - mmap_read_unlock(mm); + vma = find_extend_vma_locked(mm, bprm->p, true); + mmap_write_unlock(mm); if (!vma) return -EFAULT; diff --git a/fs/exec.c b/fs/exec.c index a466e797c8e2..a61eb256e5e4 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -205,7 +205,8 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, #ifdef CONFIG_STACK_GROWSUP if (write) { - ret = expand_downwards(bprm->vma, pos); + /* We claim to hold the lock - nobody to race with */ + ret = expand_downwards(bprm->vma, pos, true); if (ret < 0) return NULL; } @@ -853,7 +854,7 @@ int setup_arg_pages(struct linux_binprm *bprm, stack_base = vma->vm_end - stack_expand; #endif current->mm->start_stack = bprm->p; - ret = expand_stack(vma, stack_base); + ret = expand_stack_locked(vma, stack_base, true); if (ret) ret = -EFAULT; diff --git a/include/linux/mm.h b/include/linux/mm.h index 570cf906fbcc..01a016521b60 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3192,11 +3192,13 @@ extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf); extern unsigned long stack_guard_gap; /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */ -extern int expand_stack(struct vm_area_struct *vma, unsigned long address); +int expand_stack_locked(struct vm_area_struct *vma, unsigned long address, + bool write_locked); +#define expand_stack(vma,addr) expand_stack_locked(vma,addr,false) /* CONFIG_STACK_GROWSUP still needs to grow downwards at some places */ -extern int expand_downwards(struct vm_area_struct *vma, - unsigned long address); +int expand_downwards(struct vm_area_struct *vma, unsigned long address, + bool write_locked); #if VM_GROWSUP extern int expand_upwards(struct vm_area_struct *vma, unsigned long address); #else @@ -3297,6 +3299,8 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, #endif struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr); +struct vm_area_struct *find_extend_vma_locked(struct mm_struct *, + unsigned long addr, bool write_locked); int remap_pfn_range(struct vm_area_struct *, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t); int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, diff --git a/mm/memory.c b/mm/memory.c index 1dff248805bf..a81f5d0997ad 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5368,7 +5368,7 @@ struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, goto fail; } - if (expand_stack(vma, addr)) + if (expand_stack_locked(vma, addr, true)) goto fail; success: diff --git a/mm/mmap.c b/mm/mmap.c index 6d120bf1d0bc..2c44ac108a3c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1935,7 +1935,8 @@ static int acct_stack_growth(struct vm_area_struct *vma, * PA-RISC uses this for its stack; IA64 for its Register Backing Store. * vma is the last one with address > vma->vm_end. Have to extend vma. */ -int expand_upwards(struct vm_area_struct *vma, unsigned long address) +int expand_upwards(struct vm_area_struct *vma, unsigned long address, + bool write_locked) { struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *next; @@ -1959,6 +1960,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) if (gap_addr < address || gap_addr > TASK_SIZE) gap_addr = TASK_SIZE; + if (!write_locked) + return -EAGAIN; next = find_vma_intersection(mm, vma->vm_end, gap_addr); if (next && vma_is_accessible(next)) { if (!(next->vm_flags & VM_GROWSUP)) @@ -2028,7 +2031,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) /* * vma is the first one with address < vma->vm_start. Have to extend vma. */ -int expand_downwards(struct vm_area_struct *vma, unsigned long address) +int expand_downwards(struct vm_area_struct *vma, unsigned long address, + bool write_locked) { struct mm_struct *mm = vma->vm_mm; MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); @@ -2042,10 +2046,13 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) /* Enforce stack_guard_gap */ prev = mas_prev(&mas, 0); /* Check that both stack segments have the same anon_vma? */ - if (prev && !(prev->vm_flags & VM_GROWSDOWN) && - vma_is_accessible(prev)) { - if (address - prev->vm_end < stack_guard_gap) + if (prev) { + if (!(prev->vm_flags & VM_GROWSDOWN) && + vma_is_accessible(prev) && + (address - prev->vm_end < stack_guard_gap)) return -ENOMEM; + if (!write_locked && (prev->vm_end == address)) + return -EAGAIN; } if (mas_preallocate(&mas, GFP_KERNEL)) @@ -2124,13 +2131,14 @@ static int __init cmdline_parse_stack_guard_gap(char *p) __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); #ifdef CONFIG_STACK_GROWSUP -int expand_stack(struct vm_area_struct *vma, unsigned long address) +int expand_stack_locked(struct vm_area_struct *vma, unsigned long address, + bool write_locked) { - return expand_upwards(vma, address); + return expand_upwards(vma, address, write_locked); } -struct vm_area_struct * -find_extend_vma(struct mm_struct *mm, unsigned long addr) +struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, + unsigned long addr, bool write_locked) { struct vm_area_struct *vma, *prev; @@ -2138,20 +2146,25 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) vma = find_vma_prev(mm, addr, &prev); if (vma && (vma->vm_start <= addr)) return vma; - if (!prev || expand_stack(prev, addr)) + if (!prev) + return NULL; + if (expand_stack_locked(prev, addr, write_locked)) return NULL; if (prev->vm_flags & VM_LOCKED) populate_vma_page_range(prev, addr, prev->vm_end, NULL); return prev; } #else -int expand_stack(struct vm_area_struct *vma, unsigned long address) +int expand_stack_locked(struct vm_area_struct *vma, unsigned long address, + bool write_locked) { - return expand_downwards(vma, address); + if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) + return -EINVAL; + return expand_downwards(vma, address, write_locked); } -struct vm_area_struct * -find_extend_vma(struct mm_struct *mm, unsigned long addr) +struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, + unsigned long addr, bool write_locked) { struct vm_area_struct *vma; unsigned long start; @@ -2162,10 +2175,8 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) return NULL; if (vma->vm_start <= addr) return vma; - if (!(vma->vm_flags & VM_GROWSDOWN)) - return NULL; start = vma->vm_start; - if (expand_stack(vma, addr)) + if (expand_stack_locked(vma, addr, write_locked)) return NULL; if (vma->vm_flags & VM_LOCKED) populate_vma_page_range(vma, addr, start, NULL); @@ -2173,6 +2184,11 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) } #endif +struct vm_area_struct *find_extend_vma(struct mm_struct *mm, + unsigned long addr) +{ + return find_extend_vma_locked(mm, addr, false); +} EXPORT_SYMBOL_GPL(find_extend_vma); /* diff --git a/mm/nommu.c b/mm/nommu.c index f670d9979a26..f476c9ed36b3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -643,7 +643,8 @@ struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) * expand a stack to a given address * - not supported under NOMMU conditions */ -int expand_stack(struct vm_area_struct *vma, unsigned long address) +int expand_stack_locked(struct vm_area_struct *vma, unsigned long address, + bool write_locked) { return -ENOMEM; } |