diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 51 |
1 files changed, 37 insertions, 14 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 129b847d30cc..c0a3637cdb64 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -31,6 +31,7 @@ #include <linux/mempolicy.h> #include <linux/rmap.h> #include <linux/mmu_notifier.h> +#include <linux/mmdebug.h> #include <linux/perf_event.h> #include <linux/audit.h> #include <linux/khugepaged.h> @@ -134,6 +135,10 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { unsigned long free, allowed, reserve; + VM_WARN_ONCE(percpu_counter_read(&vm_committed_as) < + -(s64)vm_committed_as_batch * num_online_cpus(), + "memory commitment underflow"); + vm_acct_memory(pages); /* @@ -216,7 +221,7 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma, if (vma->vm_flags & VM_DENYWRITE) atomic_inc(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable--; + mapping_unmap_writable(mapping); flush_dcache_mmap_lock(mapping); if (unlikely(vma->vm_flags & VM_NONLINEAR)) @@ -364,20 +369,20 @@ static int browse_rb(struct rb_root *root) struct vm_area_struct *vma; vma = rb_entry(nd, struct vm_area_struct, vm_rb); if (vma->vm_start < prev) { - pr_info("vm_start %lx prev %lx\n", vma->vm_start, prev); + pr_emerg("vm_start %lx prev %lx\n", vma->vm_start, prev); bug = 1; } if (vma->vm_start < pend) { - pr_info("vm_start %lx pend %lx\n", vma->vm_start, pend); + pr_emerg("vm_start %lx pend %lx\n", vma->vm_start, pend); bug = 1; } if (vma->vm_start > vma->vm_end) { - pr_info("vm_end %lx < vm_start %lx\n", + pr_emerg("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); bug = 1; } if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { - pr_info("free gap %lx, correct %lx\n", + pr_emerg("free gap %lx, correct %lx\n", vma->rb_subtree_gap, vma_compute_subtree_gap(vma)); bug = 1; @@ -391,7 +396,7 @@ static int browse_rb(struct rb_root *root) for (nd = pn; nd; nd = rb_prev(nd)) j++; if (i != j) { - pr_info("backwards %d, forwards %d\n", j, i); + pr_emerg("backwards %d, forwards %d\n", j, i); bug = 1; } return bug ? -1 : i; @@ -426,17 +431,17 @@ static void validate_mm(struct mm_struct *mm) i++; } if (i != mm->map_count) { - pr_info("map_count %d vm_next %d\n", mm->map_count, i); + pr_emerg("map_count %d vm_next %d\n", mm->map_count, i); bug = 1; } if (highest_address != mm->highest_vm_end) { - pr_info("mm->highest_vm_end %lx, found %lx\n", + pr_emerg("mm->highest_vm_end %lx, found %lx\n", mm->highest_vm_end, highest_address); bug = 1; } i = browse_rb(&mm->mm_rb); if (i != mm->map_count) { - pr_info("map_count %d rb %d\n", mm->map_count, i); + pr_emerg("map_count %d rb %d\n", mm->map_count, i); bug = 1; } BUG_ON(bug); @@ -617,7 +622,7 @@ static void __vma_link_file(struct vm_area_struct *vma) if (vma->vm_flags & VM_DENYWRITE) atomic_dec(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable++; + atomic_inc(&mapping->i_mmap_writable); flush_dcache_mmap_lock(mapping); if (unlikely(vma->vm_flags & VM_NONLINEAR)) @@ -1572,6 +1577,17 @@ munmap_back: if (error) goto free_vma; } + if (vm_flags & VM_SHARED) { + error = mapping_map_writable(file->f_mapping); + if (error) + goto allow_write_and_free_vma; + } + + /* ->mmap() can change vma->vm_file, but must guarantee that + * vma_link() below can deny write-access if VM_DENYWRITE is set + * and map writably if VM_SHARED is set. This usually means the + * new file must not have been exposed to user-space, yet. + */ vma->vm_file = get_file(file); error = file->f_op->mmap(file, vma); if (error) @@ -1611,8 +1627,12 @@ munmap_back: vma_link(mm, vma, prev, rb_link, rb_parent); /* Once vma denies write, undo our temporary denial count */ - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); + if (file) { + if (vm_flags & VM_SHARED) + mapping_unmap_writable(file->f_mapping); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + } file = vma->vm_file; out: perf_event_mmap(vma); @@ -1641,14 +1661,17 @@ out: return addr; unmap_and_free_vma: - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); vma->vm_file = NULL; fput(file); /* Undo any partial mapping done by a device driver. */ unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); charged = 0; + if (vm_flags & VM_SHARED) + mapping_unmap_writable(file->f_mapping); +allow_write_and_free_vma: + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); free_vma: kmem_cache_free(vm_area_cachep, vma); unacct_error: |