vserver 2.0-rc4
[linux-2.6.git] / fs / exec.c
index 284207a..7620385 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -34,6 +34,7 @@
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
 #include <linux/spinlock.h>
+#include <linux/key.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 #include <linux/swap.h>
@@ -46,6 +47,7 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/rmap.h>
+#include <linux/acct.h>
 #include <linux/vs_memory.h>
 
 #include <asm/uaccess.h>
@@ -60,7 +62,7 @@ char core_pattern[65] = "core";
 /* The maximal length of core_pattern is also specified in sysctl.c */
 
 static struct linux_binfmt *formats;
-static rwlock_t binfmt_lock = RW_LOCK_UNLOCKED;
+static DEFINE_RWLOCK(binfmt_lock);
 
 int register_binfmt(struct linux_binfmt * fmt)
 {
@@ -185,6 +187,7 @@ static int count(char __user * __user * argv, int max)
                        argv++;
                        if(++i > max)
                                return -E2BIG;
+                       cond_resched();
                }
        }
        return i;
@@ -300,6 +303,7 @@ void install_arg_page(struct vm_area_struct *vma,
 {
        struct mm_struct *mm = vma->vm_mm;
        pgd_t * pgd;
+       pud_t * pud;
        pmd_t * pmd;
        pte_t * pte;
 
@@ -310,7 +314,10 @@ void install_arg_page(struct vm_area_struct *vma,
        pgd = pgd_offset(mm, address);
 
        spin_lock(&mm->page_table_lock);
-       pmd = pmd_alloc(mm, pgd, address);
+       pud = pud_alloc(mm, pgd, address);
+       if (!pud)
+               goto out;
+       pmd = pmd_alloc(mm, pud, address);
        if (!pmd)
                goto out;
        pte = pte_alloc_map(mm, pmd, address);
@@ -320,7 +327,6 @@ void install_arg_page(struct vm_area_struct *vma,
                pte_unmap(pte);
                goto out;
        }
-       // mm->rss++;
        vx_rsspages_inc(mm);
        lru_cache_add_active(page);
        set_pte(pte, pte_mkdirty(pte_mkwrite(mk_pte(
@@ -338,12 +344,16 @@ out_sig:
        force_sig(SIGKILL, current);
 }
 
-int setup_arg_pages(struct linux_binprm *bprm, int executable_stack)
+#define EXTRA_STACK_VM_PAGES   20      /* random */
+
+int setup_arg_pages(struct linux_binprm *bprm,
+                   unsigned long stack_top,
+                   int executable_stack)
 {
        unsigned long stack_base;
        struct vm_area_struct *mpnt;
        struct mm_struct *mm = current->mm;
-       int i;
+       int i, ret;
        long arg_size;
 
 #ifdef CONFIG_STACK_GROWSUP
@@ -375,14 +385,14 @@ int setup_arg_pages(struct linux_binprm *bprm, int executable_stack)
        memmove(to, to + offset, PAGE_SIZE - offset);
        kunmap(bprm->page[j - 1]);
 
-       /* Adjust bprm->p to point to the end of the strings. */
-       bprm->p = PAGE_SIZE * i - offset;
-
        /* Limit stack size to 1GB */
-       stack_base = current->rlim[RLIMIT_STACK].rlim_max;
+       stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
        if (stack_base > (1 << 30))
                stack_base = 1 << 30;
-       stack_base = PAGE_ALIGN(STACK_TOP - stack_base);
+       stack_base = PAGE_ALIGN(stack_top - stack_base);
+
+       /* Adjust bprm->p to point to the end of the strings. */
+       bprm->p = stack_base + PAGE_SIZE * i - offset;
 
        mm->arg_start = stack_base;
        arg_size = i << PAGE_SHIFT;
@@ -391,12 +401,14 @@ int setup_arg_pages(struct linux_binprm *bprm, int executable_stack)
        while (i < MAX_ARG_PAGES)
                bprm->page[i++] = NULL;
 #else
-       stack_base = STACK_TOP - MAX_ARG_PAGES * PAGE_SIZE;
-       mm->arg_start = bprm->p + stack_base;
-       arg_size = STACK_TOP - (PAGE_MASK & (unsigned long) mm->arg_start);
+       stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE;
+       bprm->p += stack_base;
+       mm->arg_start = bprm->p;
+       arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
 #endif
 
-       bprm->p += stack_base;
+       arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+
        if (bprm->loader)
                bprm->loader += stack_base;
        bprm->exec += stack_base;
@@ -418,11 +430,10 @@ int setup_arg_pages(struct linux_binprm *bprm, int executable_stack)
                mpnt->vm_mm = mm;
 #ifdef CONFIG_STACK_GROWSUP
                mpnt->vm_start = stack_base;
-               mpnt->vm_end = PAGE_MASK &
-                       (PAGE_SIZE - 1 + (unsigned long) bprm->p);
+               mpnt->vm_end = stack_base + arg_size;
 #else
-               mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
-               mpnt->vm_end = STACK_TOP;
+               mpnt->vm_end = stack_top;
+               mpnt->vm_start = mpnt->vm_end - arg_size;
 #endif
                /* Adjust stack execute permissions; explicitly enable
                 * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
@@ -435,10 +446,13 @@ int setup_arg_pages(struct linux_binprm *bprm, int executable_stack)
                        mpnt->vm_flags = VM_STACK_FLAGS;
                mpnt->vm_flags |= mm->def_flags;
                mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
-               insert_vm_struct(mm, mpnt);
-               // mm->total_vm = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
-               vx_vmpages_sub(mm, mm->total_vm -
-                       ((mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT));
+               if ((ret = insert_vm_struct(mm, mpnt))) {
+                       up_write(&mm->mmap_sem);
+                       kmem_cache_free(vm_area_cachep, mpnt);
+                       return ret;
+               }
+               vx_vmpages_sub(mm, mm->total_vm - vma_pages(mpnt));
+               mm->stack_vm = mm->total_vm;
        }
 
        for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
@@ -534,24 +548,35 @@ static int exec_mmap(struct mm_struct *mm)
        struct task_struct *tsk;
        struct mm_struct * old_mm, *active_mm;
 
-       /* Add it to the list of mm's */
-       spin_lock(&mmlist_lock);
-       list_add(&mm->mmlist, &init_mm.mmlist);
-       mmlist_nr++;
-       spin_unlock(&mmlist_lock);
-
        /* Notify parent that we're no longer interested in the old VM */
        tsk = current;
        old_mm = current->mm;
        mm_release(tsk, old_mm);
 
+       if (old_mm) {
+               /*
+                * Make sure that if there is a core dump in progress
+                * for the old mm, we get out and die instead of going
+                * through with the exec.  We must hold mmap_sem around
+                * checking core_waiters and changing tsk->mm.  The
+                * core-inducing thread will increment core_waiters for
+                * each thread whose ->mm == old_mm.
+                */
+               down_read(&old_mm->mmap_sem);
+               if (unlikely(old_mm->core_waiters)) {
+                       up_read(&old_mm->mmap_sem);
+                       return -EINTR;
+               }
+       }
        task_lock(tsk);
        active_mm = tsk->active_mm;
        tsk->mm = mm;
        tsk->active_mm = mm;
        activate_mm(active_mm, mm);
        task_unlock(tsk);
+       arch_pick_mmap_layout(mm);
        if (old_mm) {
+               up_read(&old_mm->mmap_sem);
                if (active_mm != old_mm) BUG();
                mmput(old_mm);
                return 0;
@@ -568,7 +593,7 @@ static int exec_mmap(struct mm_struct *mm)
  */
 static inline int de_thread(struct task_struct *tsk)
 {
-       struct signal_struct *newsig, *oldsig = tsk->signal;
+       struct signal_struct *sig = tsk->signal;
        struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
        spinlock_t *lock = &oldsighand->siglock;
        int count;
@@ -577,43 +602,16 @@ static inline int de_thread(struct task_struct *tsk)
         * If we don't share sighandlers, then we aren't sharing anything
         * and we can just re-use it all.
         */
-       if (atomic_read(&oldsighand->count) <= 1)
+       if (atomic_read(&oldsighand->count) <= 1) {
+               BUG_ON(atomic_read(&sig->count) != 1);
+               exit_itimers(sig);
                return 0;
+       }
 
        newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
        if (!newsighand)
                return -ENOMEM;
 
-       spin_lock_init(&newsighand->siglock);
-       atomic_set(&newsighand->count, 1);
-       memcpy(newsighand->action, oldsighand->action, sizeof(newsighand->action));
-
-       /*
-        * See if we need to allocate a new signal structure
-        */
-       newsig = NULL;
-       if (atomic_read(&oldsig->count) > 1) {
-               newsig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
-               if (!newsig) {
-                       kmem_cache_free(sighand_cachep, newsighand);
-                       return -ENOMEM;
-               }
-               atomic_set(&newsig->count, 1);
-               newsig->group_exit = 0;
-               newsig->group_exit_code = 0;
-               newsig->group_exit_task = NULL;
-               newsig->group_stop_count = 0;
-               newsig->curr_target = NULL;
-               init_sigpending(&newsig->shared_pending);
-               INIT_LIST_HEAD(&newsig->posix_timers);
-
-               newsig->tty = oldsig->tty;
-               newsig->pgrp = oldsig->pgrp;
-               newsig->session = oldsig->session;
-               newsig->leader = oldsig->leader;
-               newsig->tty_old_pgrp = oldsig->tty_old_pgrp;
-       }
-
        if (thread_group_empty(current))
                goto no_thread_group;
 
@@ -623,7 +621,7 @@ static inline int de_thread(struct task_struct *tsk)
         */
        read_lock(&tasklist_lock);
        spin_lock_irq(lock);
-       if (oldsig->group_exit) {
+       if (sig->flags & SIGNAL_GROUP_EXIT) {
                /*
                 * Another group action in progress, just
                 * return so that the signal is processed.
@@ -631,11 +629,8 @@ static inline int de_thread(struct task_struct *tsk)
                spin_unlock_irq(lock);
                read_unlock(&tasklist_lock);
                kmem_cache_free(sighand_cachep, newsighand);
-               if (newsig)
-                       kmem_cache_free(signal_cachep, newsig);
                return -EAGAIN;
        }
-       oldsig->group_exit = 1;
        zap_other_threads(current);
        read_unlock(&tasklist_lock);
 
@@ -643,16 +638,18 @@ static inline int de_thread(struct task_struct *tsk)
         * Account for the thread group leader hanging around:
         */
        count = 2;
-       if (current->pid == current->tgid)
+       if (thread_group_leader(current))
                count = 1;
-       while (atomic_read(&oldsig->count) > count) {
-               oldsig->group_exit_task = current;
-               oldsig->notify_count = count;
+       while (atomic_read(&sig->count) > count) {
+               sig->group_exit_task = current;
+               sig->notify_count = count;
                __set_current_state(TASK_UNINTERRUPTIBLE);
                spin_unlock_irq(lock);
                schedule();
                spin_lock_irq(lock);
        }
+       sig->group_exit_task = NULL;
+       sig->notify_count = 0;
        spin_unlock_irq(lock);
 
        /*
@@ -660,17 +657,17 @@ static inline int de_thread(struct task_struct *tsk)
         * do is to wait for the thread group leader to become inactive,
         * and to assume its PID:
         */
-       if (current->pid != current->tgid) {
+       if (!thread_group_leader(current)) {
                struct task_struct *leader = current->group_leader, *parent;
                struct dentry *proc_dentry1, *proc_dentry2;
-               unsigned long state, ptrace;
+               unsigned long exit_state, ptrace;
 
                /*
                 * Wait for the thread group leader to be a zombie.
                 * It should already be zombie at this point, most
                 * of the time.
                 */
-               while (leader->state != TASK_ZOMBIE)
+               while (leader->exit_state != EXIT_ZOMBIE)
                        yield();
 
                spin_lock(&leader->proc_lock);
@@ -691,6 +688,14 @@ static inline int de_thread(struct task_struct *tsk)
                 */
                ptrace = leader->ptrace;
                parent = leader->parent;
+               if (unlikely(ptrace) && unlikely(parent == current)) {
+                       /*
+                        * Joker was ptracing his own group leader,
+                        * and now he wants to be his own parent!
+                        * We can't have that.
+                        */
+                       ptrace = 0;
+               }
 
                ptrace_unlink(current);
                ptrace_unlink(leader);
@@ -714,7 +719,7 @@ static inline int de_thread(struct task_struct *tsk)
                list_del(&current->tasks);
                list_add_tail(&current->tasks, &init_task.tasks);
                current->exit_signal = SIGCHLD;
-               state = leader->state;
+               exit_state = leader->exit_state;
 
                write_unlock_irq(&tasklist_lock);
                spin_unlock(&leader->proc_lock);
@@ -722,38 +727,55 @@ static inline int de_thread(struct task_struct *tsk)
                proc_pid_flush(proc_dentry1);
                proc_pid_flush(proc_dentry2);
 
-               if (state != TASK_ZOMBIE)
+               if (exit_state != EXIT_ZOMBIE)
                        BUG();
                release_task(leader);
         }
 
+       /*
+        * Now there are really no other threads at all,
+        * so it's safe to stop telling them to kill themselves.
+        */
+       sig->flags = 0;
+
 no_thread_group:
+       BUG_ON(atomic_read(&sig->count) != 1);
+       exit_itimers(sig);
 
-       write_lock_irq(&tasklist_lock);
-       spin_lock(&oldsighand->siglock);
-       spin_lock(&newsighand->siglock);
+       if (atomic_read(&oldsighand->count) == 1) {
+               /*
+                * Now that we nuked the rest of the thread group,
+                * it turns out we are not sharing sighand any more either.
+                * So we can just keep it.
+                */
+               kmem_cache_free(sighand_cachep, newsighand);
+       } else {
+               /*
+                * Move our state over to newsighand and switch it in.
+                */
+               spin_lock_init(&newsighand->siglock);
+               atomic_set(&newsighand->count, 1);
+               memcpy(newsighand->action, oldsighand->action,
+                      sizeof(newsighand->action));
 
-       if (current == oldsig->curr_target)
-               oldsig->curr_target = next_thread(current);
-       if (newsig)
-               current->signal = newsig;
-       current->sighand = newsighand;
-       init_sigpending(&current->pending);
-       recalc_sigpending();
+               write_lock_irq(&tasklist_lock);
+               spin_lock(&oldsighand->siglock);
+               spin_lock(&newsighand->siglock);
 
-       spin_unlock(&newsighand->siglock);
-       spin_unlock(&oldsighand->siglock);
-       write_unlock_irq(&tasklist_lock);
+               current->sighand = newsighand;
+               recalc_sigpending();
 
-       if (newsig && atomic_dec_and_test(&oldsig->count))
-               kmem_cache_free(signal_cachep, oldsig);
+               spin_unlock(&newsighand->siglock);
+               spin_unlock(&oldsighand->siglock);
+               write_unlock_irq(&tasklist_lock);
 
-       if (atomic_dec_and_test(&oldsighand->count))
-               kmem_cache_free(sighand_cachep, oldsighand);
+               if (atomic_dec_and_test(&oldsighand->count))
+                       kmem_cache_free(sighand_cachep, oldsighand);
+       }
 
        if (!thread_group_empty(current))
                BUG();
-       if (current->tgid != current->pid)
+       if (!thread_group_leader(current))
                BUG();
        return 0;
 }
@@ -791,11 +813,27 @@ static inline void flush_old_files(struct files_struct * files)
        spin_unlock(&files->file_lock);
 }
 
+void get_task_comm(char *buf, struct task_struct *tsk)
+{
+       /* buf must be at least sizeof(tsk->comm) in size */
+       task_lock(tsk);
+       strncpy(buf, tsk->comm, sizeof(tsk->comm));
+       task_unlock(tsk);
+}
+
+void set_task_comm(struct task_struct *tsk, char *buf)
+{
+       task_lock(tsk);
+       strlcpy(tsk->comm, buf, sizeof(tsk->comm));
+       task_unlock(tsk);
+}
+
 int flush_old_exec(struct linux_binprm * bprm)
 {
        char * name;
        int i, ch, retval;
        struct files_struct *files;
+       char tcomm[sizeof(current->comm)];
 
        /*
         * Make sure we have a private signal table and that
@@ -836,17 +874,20 @@ int flush_old_exec(struct linux_binprm * bprm)
                if (ch == '/')
                        i = 0;
                else
-                       if (i < 15)
-                               current->comm[i++] = ch;
+                       if (i < (sizeof(tcomm) - 1))
+                               tcomm[i++] = ch;
        }
-       current->comm[i] = '\0';
+       tcomm[i] = '\0';
+       set_task_comm(current, tcomm);
 
        flush_thread();
 
        if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 
            permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
-           (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP))
+           (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
+               suid_keys(current);
                current->mm->dumpable = 0;
+       }
 
        /* An exec changes our domain. We are no longer part of the thread
           group */
@@ -880,7 +921,7 @@ int prepare_binprm(struct linux_binprm *bprm)
        mode = inode->i_mode;
        /*
         * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
-        * vfs_permission lets a non-executable through
+        * generic_permission lets a non-executable through
         */
        if (!(mode & 0111))     /* with at least _one_ execute bit set */
                return -EACCES;
@@ -940,10 +981,16 @@ static inline int unsafe_exec(struct task_struct *p)
 void compute_creds(struct linux_binprm *bprm)
 {
        int unsafe;
+
+       if (bprm->e_uid != current->uid)
+               suid_keys(current);
+       exec_keys(current);
+
        task_lock(current);
        unsafe = unsafe_exec(current);
        security_bprm_apply_creds(bprm, unsafe);
        task_unlock(current);
+       security_bprm_post_apply_creds(bprm);
 }
 
 EXPORT_SYMBOL(compute_creds);
@@ -979,7 +1026,7 @@ EXPORT_SYMBOL(remove_arg_zero);
  */
 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 {
-       int try,retval=0;
+       int try,retval;
        struct linux_binfmt *fmt;
 #ifdef __alpha__
        /* handle /sbin/loader.. */
@@ -1023,6 +1070,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
        /* kernel module loader fixup */
        /* so we don't try to load run modprobe in kernel space. */
        set_fs(USER_DS);
+       retval = -ENOENT;
        for (try=0; try<2; try++) {
                read_lock(&binfmt_lock);
                for (fmt = formats ; fmt ; fmt = fmt->next) {
@@ -1079,103 +1127,107 @@ int do_execve(char * filename,
        char __user *__user *envp,
        struct pt_regs * regs)
 {
-       struct linux_binprm bprm;
+       struct linux_binprm *bprm;
        struct file *file;
        int retval;
        int i;
 
-       file = open_exec(filename);
+       retval = -ENOMEM;
+       bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
+       if (!bprm)
+               goto out_ret;
+       memset(bprm, 0, sizeof(*bprm));
 
+       file = open_exec(filename);
        retval = PTR_ERR(file);
        if (IS_ERR(file))
-               return retval;
+               goto out_kfree;
 
-       sched_balance_exec();
-
-       bprm.p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
-       memset(bprm.page, 0, MAX_ARG_PAGES*sizeof(bprm.page[0]));
-
-       bprm.file = file;
-       bprm.filename = filename;
-       bprm.interp = filename;
-       bprm.interp_flags = 0;
-       bprm.interp_data = 0;
-       bprm.sh_bang = 0;
-       bprm.loader = 0;
-       bprm.exec = 0;
-       bprm.security = NULL;
-       bprm.mm = mm_alloc();
+       sched_exec();
+
+       bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
+
+       bprm->file = file;
+       bprm->filename = filename;
+       bprm->interp = filename;
+       bprm->mm = mm_alloc();
        retval = -ENOMEM;
-       if (!bprm.mm)
+       if (!bprm->mm)
                goto out_file;
 
-       retval = init_new_context(current, bprm.mm);
+       retval = init_new_context(current, bprm->mm);
        if (retval < 0)
                goto out_mm;
 
-       bprm.argc = count(argv, bprm.p / sizeof(void *));
-       if ((retval = bprm.argc) < 0)
+       bprm->argc = count(argv, bprm->p / sizeof(void *));
+       if ((retval = bprm->argc) < 0)
                goto out_mm;
 
-       bprm.envc = count(envp, bprm.p / sizeof(void *));
-       if ((retval = bprm.envc) < 0)
+       bprm->envc = count(envp, bprm->p / sizeof(void *));
+       if ((retval = bprm->envc) < 0)
                goto out_mm;
 
-       retval = security_bprm_alloc(&bprm);
+       retval = security_bprm_alloc(bprm);
        if (retval)
                goto out;
 
-       retval = prepare_binprm(&bprm);
+       retval = prepare_binprm(bprm);
        if (retval < 0)
                goto out;
 
-       retval = copy_strings_kernel(1, &bprm.filename, &bprm);
+       retval = copy_strings_kernel(1, &bprm->filename, bprm);
        if (retval < 0)
                goto out;
 
-       bprm.exec = bprm.p;
-       retval = copy_strings(bprm.envc, envp, &bprm);
+       bprm->exec = bprm->p;
+       retval = copy_strings(bprm->envc, envp, bprm);
        if (retval < 0)
                goto out;
 
-       retval = copy_strings(bprm.argc, argv, &bprm);
+       retval = copy_strings(bprm->argc, argv, bprm);
        if (retval < 0)
                goto out;
 
-       retval = search_binary_handler(&bprm,regs);
+       retval = search_binary_handler(bprm,regs);
        if (retval >= 0) {
-               free_arg_pages(&bprm);
+               free_arg_pages(bprm);
 
                /* execve success */
-               security_bprm_free(&bprm);
+               security_bprm_free(bprm);
+               acct_update_integrals();
+               update_mem_hiwater();
+               kfree(bprm);
                return retval;
        }
 
 out:
        /* Something went wrong, return the inode and free the argument pages*/
        for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
-               struct page * page = bprm.page[i];
+               struct page * page = bprm->page[i];
                if (page)
                        __free_page(page);
        }
 
-       if (bprm.security)
-               security_bprm_free(&bprm);
+       if (bprm->security)
+               security_bprm_free(bprm);
 
 out_mm:
-       if (bprm.mm)
-               mmdrop(bprm.mm);
+       if (bprm->mm)
+               mmdrop(bprm->mm);
 
 out_file:
-       if (bprm.file) {
-               allow_write_access(bprm.file);
-               fput(bprm.file);
+       if (bprm->file) {
+               allow_write_access(bprm->file);
+               fput(bprm->file);
        }
+
+out_kfree:
+       kfree(bprm);
+
+out_ret:
        return retval;
 }
 
-EXPORT_SYMBOL(do_execve);
-
 int set_binfmt(struct linux_binfmt *new)
 {
        struct linux_binfmt *old = current->binfmt;
@@ -1198,7 +1250,7 @@ EXPORT_SYMBOL(set_binfmt);
  * name into corename, which must have space for at least
  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
  */
-void format_corename(char *corename, const char *pattern, long signr)
+static void format_corename(char *corename, const char *pattern, long signr)
 {
        const char *pat_ptr = pattern;
        char *out_ptr = corename;
@@ -1313,6 +1365,7 @@ static void zap_threads (struct mm_struct *mm)
        struct task_struct *g, *p;
        struct task_struct *tsk = current;
        struct completion *vfork_done = tsk->vfork_done;
+       int traced = 0;
 
        /*
         * Make sure nobody is waiting for us to release the VM,
@@ -1328,10 +1381,30 @@ static void zap_threads (struct mm_struct *mm)
                if (mm == p->mm && p != tsk) {
                        force_sig_specific(SIGKILL, p);
                        mm->core_waiters++;
+                       if (unlikely(p->ptrace) &&
+                           unlikely(p->parent->mm == mm))
+                               traced = 1;
                }
        while_each_thread(g,p);
 
        read_unlock(&tasklist_lock);
+
+       if (unlikely(traced)) {
+               /*
+                * We are zapping a thread and the thread it ptraces.
+                * If the tracee went into a ptrace stop for exit tracing,
+                * we could deadlock since the tracer is waiting for this
+                * coredump to finish.  Detach them so they can both die.
+                */
+               write_lock_irq(&tasklist_lock);
+               do_each_thread(g,p) {
+                       if (mm == p->mm && p != tsk &&
+                           p->ptrace && p->parent->mm == mm) {
+                               __ptrace_unlink(p);
+                       }
+               } while_each_thread(g,p);
+               write_unlock_irq(&tasklist_lock);
+       }
 }
 
 static void coredump_wait(struct mm_struct *mm)
@@ -1362,7 +1435,6 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
        struct file * file;
        int retval = 0;
 
-       lock_kernel();
        binfmt = current->binfmt;
        if (!binfmt || !binfmt->core_dump)
                goto fail;
@@ -1373,14 +1445,29 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
        }
        mm->dumpable = 0;
        init_completion(&mm->core_done);
-       current->signal->group_exit = 1;
+       spin_lock_irq(&current->sighand->siglock);
+       current->signal->flags = SIGNAL_GROUP_EXIT;
        current->signal->group_exit_code = exit_code;
+       spin_unlock_irq(&current->sighand->siglock);
        coredump_wait(mm);
 
-       if (current->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
+       /*
+        * Clear any false indication of pending signals that might
+        * be seen by the filesystem code called to write the core file.
+        */
+       current->signal->group_stop_count = 0;
+       clear_thread_flag(TIF_SIGPENDING);
+
+       if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
                goto fail_unlock;
 
-       format_corename(corename, core_pattern, signr);
+       /*
+        * lock_kernel() because format_corename() is controlled by sysctl, which
+        * uses lock_kernel()
+        */
+       lock_kernel();
+       format_corename(corename, core_pattern, signr);
+       unlock_kernel();
        file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600);
        if (IS_ERR(file))
                goto fail_unlock;
@@ -1401,12 +1488,12 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 
        retval = binfmt->core_dump(signr, regs, file);
 
-       current->signal->group_exit_code |= 0x80;
+       if (retval)
+               current->signal->group_exit_code |= 0x80;
 close_fail:
        filp_close(file, NULL);
 fail_unlock:
        complete_all(&mm->core_done);
 fail:
-       unlock_kernel();
        return retval;
 }