[RFC 08/18] limits: track RLIMIT_DATA actual max

[Topi Miettinen]

Track maximum size of data VM, presented in /proc/self/limits.

Signed-off-by: Topi Miettinen <toiwo...@gmail.com>
---
 arch/x86/ia32/ia32_aout.c | 1 +
 fs/binfmt_aout.c          | 1 +
 fs/binfmt_flat.c          | 1 +
 kernel/sys.c              | 2 ++
 mm/mmap.c                 | 6 +++++-
 5 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index cb26f18..8a7d502 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -398,6 +398,7 @@ beyond_if:
        regs->r8 = regs->r9 = regs->r10 = regs->r11 =
        regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
        set_fs(USER_DS);
+       bump_limit(RLIMIT_DATA, ex.a_data + ex.a_bss);
        return 0;
 }
 
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index ae1b540..86c6548 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -330,6 +330,7 @@ beyond_if:
        regs->gp = ex.a_gpvalue;
 #endif
        start_thread(regs, ex.a_entry, current->mm->start_stack);
+       bump_limit(RLIMIT_DATA, ex.a_data + ex.a_bss);
        return 0;
 }
 
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index caf9e39..e309dad 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -792,6 +792,7 @@ static int load_flat_file(struct linux_binprm * bprm,
                        libinfo->lib_list[id].start_brk) +      /* start brk */
                        stack_len);
 
+       bump_limit(RLIMIT_DATA, data_len + bss_len);
        return 0;
 err:
        return ret;
diff --git a/kernel/sys.c b/kernel/sys.c
index 89d5be4..6629f6f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1896,6 +1896,8 @@ static int prctl_set_mm_map(int opt, const void __user 
*addr, unsigned long data
        if (prctl_map.auxv_size)
                memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
 
+       bump_limit(RLIMIT_DATA, mm->end_data - mm->start_data);
+
        up_write(&mm->mmap_sem);
        return 0;
 }
diff --git a/mm/mmap.c b/mm/mmap.c
index de2c176..61867de 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -228,6 +228,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
                goto out;
 
 set_brk:
+       bump_rlimit(RLIMIT_DATA, (brk - mm->start_brk) +
+                   (mm->end_data - mm->start_data));
        mm->brk = brk;
        populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
        up_write(&mm->mmap_sem);
@@ -2924,8 +2926,10 @@ void vm_stat_account(struct mm_struct *mm, vm_flags_t 
flags, long npages)
                mm->exec_vm += npages;
        else if (is_stack_mapping(flags))
                mm->stack_vm += npages;
-       else if (is_data_mapping(flags))
+       else if (is_data_mapping(flags)) {
                mm->data_vm += npages;
+               bump_rlimit(RLIMIT_DATA, mm->data_vm << PAGE_SHIFT);
+       }
 }
 
 static int special_mapping_fault(struct vm_area_struct *vma,
-- 
2.8.1