Btrfs: Avoid superfluous tree-log writeout

[firefly-linux-kernel-4.4.55.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index ba112bd4a339c93995b66bd639175a37c95a084b..56da15f6d77100f5c604ba0eabb5df111e9379aa 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -572,6 +572,9 @@ int setup_arg_pages(struct linux_binprm *bprm,
        struct vm_area_struct *prev = NULL;
        unsigned long vm_flags;
        unsigned long stack_base;
+       unsigned long stack_size;
+       unsigned long stack_expand;
+       unsigned long rlim_stack;
 
 #ifdef CONFIG_STACK_GROWSUP
        /* Limit stack size to 1GB */
@@ -628,10 +631,23 @@ int setup_arg_pages(struct linux_binprm *bprm,
                        goto out_unlock;
        }
 
+       stack_expand = EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+       stack_size = vma->vm_end - vma->vm_start;
+       /*
+        * Align this down to a page boundary as expand_stack
+        * will align it up.
+        */
+       rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK;
 #ifdef CONFIG_STACK_GROWSUP
-       stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+       if (stack_size + stack_expand > rlim_stack)
+               stack_base = vma->vm_start + rlim_stack;
+       else
+               stack_base = vma->vm_end + stack_expand;
 #else
-       stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+       if (stack_size + stack_expand > rlim_stack)
+               stack_base = vma->vm_end - rlim_stack;
+       else
+               stack_base = vma->vm_start - stack_expand;
 #endif
        ret = expand_stack(vma, stack_base);
        if (ret)
@@ -931,9 +947,7 @@ void set_task_comm(struct task_struct *tsk, char *buf)
 
 int flush_old_exec(struct linux_binprm * bprm)
 {
-       char * name;
-       int i, ch, retval;
-       char tcomm[sizeof(current->comm)];
+       int retval;
 
        /*
         * Make sure we have a private signal table and that
@@ -954,6 +968,25 @@ int flush_old_exec(struct linux_binprm * bprm)
 
        bprm->mm = NULL;                /* We're using it now */
 
+       current->flags &= ~PF_RANDOMIZE;
+       flush_thread();
+       current->personality &= ~bprm->per_clear;
+
+       return 0;
+
+out:
+       return retval;
+}
+EXPORT_SYMBOL(flush_old_exec);
+
+void setup_new_exec(struct linux_binprm * bprm)
+{
+       int i, ch;
+       char * name;
+       char tcomm[sizeof(current->comm)];
+
+       arch_pick_mmap_layout(current->mm);
+
        /* This is the point of no return */
        current->sas_ss_sp = current->sas_ss_size = 0;
 
@@ -975,9 +1008,6 @@ int flush_old_exec(struct linux_binprm * bprm)
        tcomm[i] = '\0';
        set_task_comm(current, tcomm);
 
-       current->flags &= ~PF_RANDOMIZE;
-       flush_thread();
-
        /* Set the new mm task size. We have to do that late because it may
         * depend on TIF_32BIT which is only updated in flush_thread() on
         * some architectures like powerpc
@@ -993,8 +1023,6 @@ int flush_old_exec(struct linux_binprm * bprm)
                set_dumpable(current->mm, suid_dumpable);
        }
 
-       current->personality &= ~bprm->per_clear;
-
        /*
         * Flush performance counters when crossing a
         * security domain:
@@ -1009,14 +1037,8 @@ int flush_old_exec(struct linux_binprm * bprm)
                        
        flush_signal_handlers(current, 0);
        flush_old_files(current->files);
-
-       return 0;
-
-out:
-       return retval;
 }
-
-EXPORT_SYMBOL(flush_old_exec);
+EXPORT_SYMBOL(setup_new_exec);
 
 /*
  * Prepare credentials and lock ->cred_guard_mutex.
@@ -1357,8 +1379,6 @@ int do_execve(char * filename,
        if (retval < 0)
                goto out;
 
-       current->stack_start = current->mm->start_stack;
-
        /* execve succeeded */
        current->fs->in_exec = 0;
        current->in_execve = 0;
@@ -1891,8 +1911,9 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
        /*
         * Dont allow local users get cute and trick others to coredump
         * into their pre-created files:
+        * Note, this is not relevant for pipes
         */
-       if (inode->i_uid != current_fsuid())
+       if (!ispipe && (inode->i_uid != current_fsuid()))
                goto close_fail;
        if (!file->f_op)
                goto close_fail;