usb: gadget: include <linux/prefetch.h> to fix compiling error
[linux-2.6.git] / fs / exec.c
index 2d94552..ea5f748 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -42,7 +42,6 @@
 #include <linux/pid_namespace.h>
 #include <linux/module.h>
 #include <linux/namei.h>
-#include <linux/proc_fs.h>
 #include <linux/mount.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
@@ -54,6 +53,8 @@
 #include <linux/fsnotify.h>
 #include <linux/fs_struct.h>
 #include <linux/pipe_fs_i.h>
+#include <linux/oom.h>
+#include <linux/compat.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -65,6 +66,12 @@ char core_pattern[CORENAME_MAX_SIZE] = "core";
 unsigned int core_pipe_limit;
 int suid_dumpable = 0;
 
+struct core_name {
+       char *corename;
+       int used, size;
+};
+static atomic_t call_count = ATOMIC_INIT(1);
+
 /* The maximal length of core_pattern is also specified in sysctl.c */
 
 static LIST_HEAD(formats);
@@ -108,13 +115,16 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
        struct file *file;
        char *tmp = getname(library);
        int error = PTR_ERR(tmp);
+       static const struct open_flags uselib_flags = {
+               .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+               .acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN,
+               .intent = LOOKUP_OPEN
+       };
 
        if (IS_ERR(tmp))
                goto out;
 
-       file = do_filp_open(AT_FDCWD, tmp,
-                               O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
-                               MAY_READ | MAY_EXEC | MAY_OPEN);
+       file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW);
        putname(tmp);
        error = PTR_ERR(file);
        if (IS_ERR(file))
@@ -156,6 +166,30 @@ out:
 }
 
 #ifdef CONFIG_MMU
+/*
+ * The nascent bprm->mm is not visible until exec_mmap() but it can
+ * use a lot of memory, account these pages in current->mm temporary
+ * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
+ * change the counter back via acct_arg_size(0).
+ */
+static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+       struct mm_struct *mm = current->mm;
+       long diff = (long)(pages - bprm->vma_pages);
+
+       if (!mm || !diff)
+               return;
+
+       bprm->vma_pages = pages;
+
+#ifdef SPLIT_RSS_COUNTING
+       add_mm_counter(mm, MM_ANONPAGES, diff);
+#else
+       spin_lock(&mm->page_table_lock);
+       add_mm_counter(mm, MM_ANONPAGES, diff);
+       spin_unlock(&mm->page_table_lock);
+#endif
+}
 
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                int write)
@@ -165,7 +199,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 
 #ifdef CONFIG_STACK_GROWSUP
        if (write) {
-               ret = expand_stack_downwards(bprm->vma, pos);
+               ret = expand_downwards(bprm->vma, pos);
                if (ret < 0)
                        return NULL;
        }
@@ -179,6 +213,8 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
                struct rlimit *rlim;
 
+               acct_arg_size(bprm, size / PAGE_SIZE);
+
                /*
                 * We've historically supported up to 32 pages (ARG_MAX)
                 * of argument strings even with small stacks
@@ -247,6 +283,11 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
        vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
        vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
        INIT_LIST_HEAD(&vma->anon_vma_chain);
+
+       err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
+       if (err)
+               goto err;
+
        err = insert_vm_struct(mm, vma);
        if (err)
                goto err;
@@ -269,6 +310,10 @@ static bool valid_arg_len(struct linux_binprm *bprm, long len)
 
 #else
 
+static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+}
+
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                int write)
 {
@@ -358,24 +403,61 @@ err:
        return err;
 }
 
+struct user_arg_ptr {
+#ifdef CONFIG_COMPAT
+       bool is_compat;
+#endif
+       union {
+               const char __user *const __user *native;
+#ifdef CONFIG_COMPAT
+               compat_uptr_t __user *compat;
+#endif
+       } ptr;
+};
+
+static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
+{
+       const char __user *native;
+
+#ifdef CONFIG_COMPAT
+       if (unlikely(argv.is_compat)) {
+               compat_uptr_t compat;
+
+               if (get_user(compat, argv.ptr.compat + nr))
+                       return ERR_PTR(-EFAULT);
+
+               return compat_ptr(compat);
+       }
+#endif
+
+       if (get_user(native, argv.ptr.native + nr))
+               return ERR_PTR(-EFAULT);
+
+       return native;
+}
+
 /*
  * count() counts the number of strings in array ARGV.
  */
-static int count(const char __user * const __user * argv, int max)
+static int count(struct user_arg_ptr argv, int max)
 {
        int i = 0;
 
-       if (argv != NULL) {
+       if (argv.ptr.native != NULL) {
                for (;;) {
-                       const char __user * p;
+                       const char __user *p = get_user_arg_ptr(argv, i);
 
-                       if (get_user(p, argv))
-                               return -EFAULT;
                        if (!p)
                                break;
-                       argv++;
+
+                       if (IS_ERR(p))
+                               return -EFAULT;
+
                        if (i++ >= max)
                                return -E2BIG;
+
+                       if (fatal_signal_pending(current))
+                               return -ERESTARTNOHAND;
                        cond_resched();
                }
        }
@@ -387,7 +469,7 @@ static int count(const char __user * const __user * argv, int max)
  * processes's memory to the new process's stack.  The call to get_user_pages()
  * ensures the destination page is created and not swapped out.
  */
-static int copy_strings(int argc, const char __user *const __user *argv,
+static int copy_strings(int argc, struct user_arg_ptr argv,
                        struct linux_binprm *bprm)
 {
        struct page *kmapped_page = NULL;
@@ -400,16 +482,18 @@ static int copy_strings(int argc, const char __user *const __user *argv,
                int len;
                unsigned long pos;
 
-               if (get_user(str, argv+argc) ||
-                               !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
-                       ret = -EFAULT;
+               ret = -EFAULT;
+               str = get_user_arg_ptr(argv, argc);
+               if (IS_ERR(str))
                        goto out;
-               }
 
-               if (!valid_arg_len(bprm, len)) {
-                       ret = -E2BIG;
+               len = strnlen_user(str, MAX_ARG_STRLEN);
+               if (!len)
+                       goto out;
+
+               ret = -E2BIG;
+               if (!valid_arg_len(bprm, len))
                        goto out;
-               }
 
                /* We're going to work our way backwords. */
                pos = bprm->p;
@@ -419,6 +503,12 @@ static int copy_strings(int argc, const char __user *const __user *argv,
                while (len > 0) {
                        int offset, bytes_to_copy;
 
+                       if (fatal_signal_pending(current)) {
+                               ret = -ERESTARTNOHAND;
+                               goto out;
+                       }
+                       cond_resched();
+
                        offset = pos % PAGE_SIZE;
                        if (offset == 0)
                                offset = PAGE_SIZE;
@@ -470,14 +560,19 @@ out:
 /*
  * Like copy_strings, but get argv and its values from kernel memory.
  */
-int copy_strings_kernel(int argc, const char *const *argv,
+int copy_strings_kernel(int argc, const char *const *__argv,
                        struct linux_binprm *bprm)
 {
        int r;
        mm_segment_t oldfs = get_fs();
+       struct user_arg_ptr argv = {
+               .ptr.native = (const char __user *const  __user *)__argv,
+       };
+
        set_fs(KERNEL_DS);
-       r = copy_strings(argc, (const char __user *const  __user *)argv, bprm);
+       r = copy_strings(argc, argv, bprm);
        set_fs(oldfs);
+
        return r;
 }
 EXPORT_SYMBOL(copy_strings_kernel);
@@ -504,7 +599,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
        unsigned long length = old_end - old_start;
        unsigned long new_start = old_start - shift;
        unsigned long new_end = old_end - shift;
-       struct mmu_gather *tlb;
+       struct mmu_gather tlb;
 
        BUG_ON(new_start > new_end);
 
@@ -530,12 +625,12 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
                return -ENOMEM;
 
        lru_add_drain();
-       tlb = tlb_gather_mmu(mm, 0);
+       tlb_gather_mmu(&tlb, mm, 0);
        if (new_end > old_start) {
                /*
                 * when the old and new regions overlap clear from new_end.
                 */
-               free_pgd_range(tlb, new_end, old_end, new_end,
+               free_pgd_range(&tlb, new_end, old_end, new_end,
                        vma->vm_next ? vma->vm_next->vm_start : 0);
        } else {
                /*
@@ -544,10 +639,10 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
                 * have constraints on va-space that make this illegal (IA64) -
                 * for the others its just a little faster.
                 */
-               free_pgd_range(tlb, old_start, old_end, new_end,
+               free_pgd_range(&tlb, old_start, old_end, new_end,
                        vma->vm_next ? vma->vm_next->vm_start : 0);
        }
-       tlb_finish_mmu(tlb, new_end, old_end);
+       tlb_finish_mmu(&tlb, new_end, old_end);
 
        /*
         * Shrink the vma to just the new range.  Always succeeds.
@@ -594,6 +689,11 @@ int setup_arg_pages(struct linux_binprm *bprm,
 #else
        stack_top = arch_align_stack(stack_top);
        stack_top = PAGE_ALIGN(stack_top);
+
+       if (unlikely(stack_top < mmap_min_addr) ||
+           unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
+               return -ENOMEM;
+
        stack_shift = vma->vm_end - stack_top;
 
        bprm->p -= stack_shift;
@@ -670,10 +770,13 @@ struct file *open_exec(const char *name)
 {
        struct file *file;
        int err;
+       static const struct open_flags open_exec_flags = {
+               .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+               .acc_mode = MAY_EXEC | MAY_OPEN,
+               .intent = LOOKUP_OPEN
+       };
 
-       file = do_filp_open(AT_FDCWD, name,
-                               O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
-                               MAY_EXEC | MAY_OPEN);
+       file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW);
        if (IS_ERR(file))
                goto out;
 
@@ -745,6 +848,10 @@ static int exec_mmap(struct mm_struct *mm)
        tsk->mm = mm;
        tsk->active_mm = mm;
        activate_mm(active_mm, mm);
+       if (old_mm && tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
+               atomic_dec(&old_mm->oom_disable_count);
+               atomic_inc(&tsk->mm->oom_disable_count);
+       }
        task_unlock(tsk);
        arch_pick_mmap_layout(mm);
        if (old_mm) {
@@ -943,6 +1050,7 @@ char *get_task_comm(char *buf, struct task_struct *tsk)
        task_unlock(tsk);
        return buf;
 }
+EXPORT_SYMBOL_GPL(get_task_comm);
 
 void set_task_comm(struct task_struct *tsk, char *buf)
 {
@@ -978,13 +1086,14 @@ int flush_old_exec(struct linux_binprm * bprm)
        /*
         * Release all of the old mmap stuff
         */
+       acct_arg_size(bprm, 0);
        retval = exec_mmap(bprm->mm);
        if (retval)
                goto out;
 
        bprm->mm = NULL;                /* We're using it now */
 
-       current->flags &= ~PF_RANDOMIZE;
+       current->flags &= ~(PF_RANDOMIZE | PF_KTHREAD);
        flush_thread();
        current->personality &= ~bprm->per_clear;
 
@@ -1064,14 +1173,14 @@ EXPORT_SYMBOL(setup_new_exec);
  */
 int prepare_bprm_creds(struct linux_binprm *bprm)
 {
-       if (mutex_lock_interruptible(&current->cred_guard_mutex))
+       if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
                return -ERESTARTNOINTR;
 
        bprm->cred = prepare_exec_creds();
        if (likely(bprm->cred))
                return 0;
 
-       mutex_unlock(&current->cred_guard_mutex);
+       mutex_unlock(&current->signal->cred_guard_mutex);
        return -ENOMEM;
 }
 
@@ -1079,7 +1188,7 @@ void free_bprm(struct linux_binprm *bprm)
 {
        free_arg_pages(bprm);
        if (bprm->cred) {
-               mutex_unlock(&current->cred_guard_mutex);
+               mutex_unlock(&current->signal->cred_guard_mutex);
                abort_creds(bprm->cred);
        }
        kfree(bprm);
@@ -1100,13 +1209,13 @@ void install_exec_creds(struct linux_binprm *bprm)
         * credentials; any time after this it may be unlocked.
         */
        security_bprm_committed_creds(bprm);
-       mutex_unlock(&current->cred_guard_mutex);
+       mutex_unlock(&current->signal->cred_guard_mutex);
 }
 EXPORT_SYMBOL(install_exec_creds);
 
 /*
  * determine how safe it is to execute the proposed program
- * - the caller must hold current->cred_guard_mutex to protect against
+ * - the caller must hold ->cred_guard_mutex to protect against
  *   PTRACE_ATTACH
  */
 int check_unsafe_exec(struct linux_binprm *bprm)
@@ -1317,10 +1426,10 @@ EXPORT_SYMBOL(search_binary_handler);
 /*
  * sys_execve() executes a new program.
  */
-int do_execve(const char * filename,
-       const char __user *const __user *argv,
-       const char __user *const __user *envp,
-       struct pt_regs * regs)
+static int do_execve_common(const char *filename,
+                               struct user_arg_ptr argv,
+                               struct user_arg_ptr envp,
+                               struct pt_regs *regs)
 {
        struct linux_binprm *bprm;
        struct file *file;
@@ -1387,7 +1496,6 @@ int do_execve(const char * filename,
        if (retval < 0)
                goto out;
 
-       current->flags &= ~PF_KTHREAD;
        retval = search_binary_handler(bprm,regs);
        if (retval < 0)
                goto out;
@@ -1402,8 +1510,10 @@ int do_execve(const char * filename,
        return retval;
 
 out:
-       if (bprm->mm)
-               mmput (bprm->mm);
+       if (bprm->mm) {
+               acct_arg_size(bprm, 0);
+               mmput(bprm->mm);
+       }
 
 out_file:
        if (bprm->file) {
@@ -1426,6 +1536,34 @@ out_ret:
        return retval;
 }
 
+int do_execve(const char *filename,
+       const char __user *const __user *__argv,
+       const char __user *const __user *__envp,
+       struct pt_regs *regs)
+{
+       struct user_arg_ptr argv = { .ptr.native = __argv };
+       struct user_arg_ptr envp = { .ptr.native = __envp };
+       return do_execve_common(filename, argv, envp, regs);
+}
+
+#ifdef CONFIG_COMPAT
+int compat_do_execve(char *filename,
+       compat_uptr_t __user *__argv,
+       compat_uptr_t __user *__envp,
+       struct pt_regs *regs)
+{
+       struct user_arg_ptr argv = {
+               .is_compat = true,
+               .ptr.compat = __argv,
+       };
+       struct user_arg_ptr envp = {
+               .is_compat = true,
+               .ptr.compat = __envp,
+       };
+       return do_execve_common(filename, argv, envp, regs);
+}
+#endif
+
 void set_binfmt(struct linux_binfmt *new)
 {
        struct mm_struct *mm = current->mm;
@@ -1440,127 +1578,186 @@ void set_binfmt(struct linux_binfmt *new)
 
 EXPORT_SYMBOL(set_binfmt);
 
+static int expand_corename(struct core_name *cn)
+{
+       char *old_corename = cn->corename;
+
+       cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
+       cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
+
+       if (!cn->corename) {
+               kfree(old_corename);
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+static int cn_printf(struct core_name *cn, const char *fmt, ...)
+{
+       char *cur;
+       int need;
+       int ret;
+       va_list arg;
+
+       va_start(arg, fmt);
+       need = vsnprintf(NULL, 0, fmt, arg);
+       va_end(arg);
+
+       if (likely(need < cn->size - cn->used - 1))
+               goto out_printf;
+
+       ret = expand_corename(cn);
+       if (ret)
+               goto expand_fail;
+
+out_printf:
+       cur = cn->corename + cn->used;
+       va_start(arg, fmt);
+       vsnprintf(cur, need + 1, fmt, arg);
+       va_end(arg);
+       cn->used += need;
+       return 0;
+
+expand_fail:
+       return ret;
+}
+
+static int cn_print_exe_file(struct core_name *cn)
+{
+       struct file *exe_file;
+       char *pathbuf, *path, *p;
+       int ret;
+
+       exe_file = get_mm_exe_file(current->mm);
+       if (!exe_file)
+               return cn_printf(cn, "(unknown)");
+
+       pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
+       if (!pathbuf) {
+               ret = -ENOMEM;
+               goto put_exe_file;
+       }
+
+       path = d_path(&exe_file->f_path, pathbuf, PATH_MAX);
+       if (IS_ERR(path)) {
+               ret = PTR_ERR(path);
+               goto free_buf;
+       }
+
+       for (p = path; *p; p++)
+               if (*p == '/')
+                       *p = '!';
+
+       ret = cn_printf(cn, "%s", path);
+
+free_buf:
+       kfree(pathbuf);
+put_exe_file:
+       fput(exe_file);
+       return ret;
+}
+
 /* format_corename will inspect the pattern parameter, and output a
  * name into corename, which must have space for at least
  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
  */
-static int format_corename(char *corename, long signr)
+static int format_corename(struct core_name *cn, long signr)
 {
        const struct cred *cred = current_cred();
        const char *pat_ptr = core_pattern;
        int ispipe = (*pat_ptr == '|');
-       char *out_ptr = corename;
-       char *const out_end = corename + CORENAME_MAX_SIZE;
-       int rc;
        int pid_in_pattern = 0;
+       int err = 0;
+
+       cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
+       cn->corename = kmalloc(cn->size, GFP_KERNEL);
+       cn->used = 0;
+
+       if (!cn->corename)
+               return -ENOMEM;
 
        /* Repeat as long as we have more pattern to process and more output
           space */
        while (*pat_ptr) {
                if (*pat_ptr != '%') {
-                       if (out_ptr == out_end)
+                       if (*pat_ptr == 0)
                                goto out;
-                       *out_ptr++ = *pat_ptr++;
+                       err = cn_printf(cn, "%c", *pat_ptr++);
                } else {
                        switch (*++pat_ptr) {
+                       /* single % at the end, drop that */
                        case 0:
                                goto out;
                        /* Double percent, output one percent */
                        case '%':
-                               if (out_ptr == out_end)
-                                       goto out;
-                               *out_ptr++ = '%';
+                               err = cn_printf(cn, "%c", '%');
                                break;
                        /* pid */
                        case 'p':
                                pid_in_pattern = 1;
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%d", task_tgid_vnr(current));
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%d",
+                                             task_tgid_vnr(current));
                                break;
                        /* uid */
                        case 'u':
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%d", cred->uid);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%d", cred->uid);
                                break;
                        /* gid */
                        case 'g':
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%d", cred->gid);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%d", cred->gid);
                                break;
                        /* signal that caused the coredump */
                        case 's':
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%ld", signr);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%ld", signr);
                                break;
                        /* UNIX time of coredump */
                        case 't': {
                                struct timeval tv;
                                do_gettimeofday(&tv);
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%lu", tv.tv_sec);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%lu", tv.tv_sec);
                                break;
                        }
                        /* hostname */
                        case 'h':
                                down_read(&uts_sem);
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%s", utsname()->nodename);
+                               err = cn_printf(cn, "%s",
+                                             utsname()->nodename);
                                up_read(&uts_sem);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
                                break;
                        /* executable */
                        case 'e':
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%s", current->comm);
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%s", current->comm);
+                               break;
+                       case 'E':
+                               err = cn_print_exe_file(cn);
                                break;
                        /* core limit size */
                        case 'c':
-                               rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%lu", rlimit(RLIMIT_CORE));
-                               if (rc > out_end - out_ptr)
-                                       goto out;
-                               out_ptr += rc;
+                               err = cn_printf(cn, "%lu",
+                                             rlimit(RLIMIT_CORE));
                                break;
                        default:
                                break;
                        }
                        ++pat_ptr;
                }
+
+               if (err)
+                       return err;
        }
+
        /* Backward compatibility with core_uses_pid:
         *
         * If core_pattern does not include a %p (as is the default)
         * and core_uses_pid is set, then .%pid will be appended to
         * the filename. Do not do this for piped commands. */
        if (!ispipe && !pid_in_pattern && core_uses_pid) {
-               rc = snprintf(out_ptr, out_end - out_ptr,
-                             ".%d", task_tgid_vnr(current));
-               if (rc > out_end - out_ptr)
-                       goto out;
-               out_ptr += rc;
+               err = cn_printf(cn, ".%d", task_tgid_vnr(current));
+               if (err)
+                       return err;
        }
 out:
-       *out_ptr = 0;
        return ispipe;
 }
 
@@ -1575,6 +1772,7 @@ static int zap_process(struct task_struct *start, int exit_code)
 
        t = start;
        do {
+               task_clear_group_stop_pending(t);
                if (t != current && t->mm) {
                        sigaddset(&t->pending.signal, SIGKILL);
                        signal_wake_up(t, 1);
@@ -1791,7 +1989,7 @@ static void wait_for_dump_helpers(struct file *file)
 
 
 /*
- * uhm_pipe_setup
+ * umh_pipe_setup
  * helper function to customize the process used
  * to collect the core in userspace.  Specifically
  * it sets up a pipe and installs it as fd 0 (stdin)
@@ -1837,7 +2035,7 @@ static int umh_pipe_setup(struct subprocess_info *info)
 void do_coredump(long signr, int exit_code, struct pt_regs *regs)
 {
        struct core_state core_state;
-       char corename[CORENAME_MAX_SIZE + 1];
+       struct core_name cn;
        struct mm_struct *mm = current->mm;
        struct linux_binfmt * binfmt;
        const struct cred *old_cred;
@@ -1892,7 +2090,13 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         */
        clear_thread_flag(TIF_SIGPENDING);
 
-       ispipe = format_corename(corename, signr);
+       ispipe = format_corename(&cn, signr);
+
+       if (ispipe == -ENOMEM) {
+               printk(KERN_WARNING "format_corename failed\n");
+               printk(KERN_WARNING "Aborting core\n");
+               goto fail_corename;
+       }
 
        if (ispipe) {
                int dump_count;
@@ -1929,7 +2133,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                        goto fail_dropcount;
                }
 
-               helper_argv = argv_split(GFP_KERNEL, corename+1, NULL);
+               helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
                if (!helper_argv) {
                        printk(KERN_WARNING "%s failed to allocate memory\n",
                               __func__);
@@ -1942,7 +2146,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                argv_free(helper_argv);
                if (retval) {
                        printk(KERN_INFO "Core dump to %s pipe failed\n",
-                              corename);
+                              cn.corename);
                        goto close_fail;
                }
        } else {
@@ -1951,7 +2155,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                if (cprm.limit < binfmt->min_coredump)
                        goto fail_unlock;
 
-               cprm.file = filp_open(corename,
+               cprm.file = filp_open(cn.corename,
                                 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
                                 0600);
                if (IS_ERR(cprm.file))
@@ -1993,6 +2197,8 @@ fail_dropcount:
        if (ispipe)
                atomic_dec(&core_dump_count);
 fail_unlock:
+       kfree(cn.corename);
+fail_corename:
        coredump_finish(mm);
        revert_creds(old_cred);
 fail_creds:
@@ -2000,3 +2206,43 @@ fail_creds:
 fail:
        return;
 }
+
+/*
+ * Core dumping helper functions.  These are the only things you should
+ * do on a core-file: use only these functions to write out all the
+ * necessary info.
+ */
+int dump_write(struct file *file, const void *addr, int nr)
+{
+       return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+}
+EXPORT_SYMBOL(dump_write);
+
+int dump_seek(struct file *file, loff_t off)
+{
+       int ret = 1;
+
+       if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
+               if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
+                       return 0;
+       } else {
+               char *buf = (char *)get_zeroed_page(GFP_KERNEL);
+
+               if (!buf)
+                       return 0;
+               while (off > 0) {
+                       unsigned long n = off;
+
+                       if (n > PAGE_SIZE)
+                               n = PAGE_SIZE;
+                       if (!dump_write(file, buf, n)) {
+                               ret = 0;
+                               break;
+                       }
+                       off -= n;
+               }
+               free_page((unsigned long)buf);
+       }
+       return ret;
+}
+EXPORT_SYMBOL(dump_seek);