[PATCH] deal with deadlocks in audit_free()

Don't assume that audit_log_exit() et.al. are called for the context of
current; pass task explictly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 7f160df..4052f0a 100644 (file)
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -536,13 +536,13 @@ error_path:
        return;
 }
 
-static void audit_log_task_info(struct audit_buffer *ab, gfp_t gfp_mask)
+static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk, gfp_t gfp_mask)
 {
-       char name[sizeof(current->comm)];
-       struct mm_struct *mm = current->mm;
+       char name[sizeof(tsk->comm)];
+       struct mm_struct *mm = tsk->mm;
        struct vm_area_struct *vma;
 
-       get_task_comm(name, current);
+       get_task_comm(name, tsk);
        audit_log_format(ab, " comm=");
        audit_log_untrustedstring(ab, name);
 
@@ -551,7 +551,7 @@ static void audit_log_task_info(struct audit_buffer *ab, gfp_t gfp_mask)
 
        /*
         * this is brittle; all callers that pass GFP_ATOMIC will have
-        * NULL current->mm and we won't get here.
+        * NULL tsk->mm and we won't get here.
         */
        down_read(&mm->mmap_sem);
        vma = mm->mmap;
@@ -569,7 +569,7 @@ static void audit_log_task_info(struct audit_buffer *ab, gfp_t gfp_mask)
        audit_log_task_context(ab, gfp_mask);
 }
 
-static void audit_log_exit(struct audit_context *context, gfp_t gfp_mask)
+static void audit_log_exit(struct audit_context *context, struct task_struct *tsk, gfp_t gfp_mask)
 {
        int i;
        struct audit_buffer *ab;
@@ -587,8 +587,8 @@ static void audit_log_exit(struct audit_context *context, gfp_t gfp_mask)
                audit_log_format(ab, " success=%s exit=%ld", 
                                 (context->return_valid==AUDITSC_SUCCESS)?"yes":"no",
                                 context->return_code);
-       if (current->signal->tty && current->signal->tty->name)
-               tty = current->signal->tty->name;
+       if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
+               tty = tsk->signal->tty->name;
        else
                tty = "(none)";
        audit_log_format(ab,
@@ -720,7 +720,7 @@ void audit_free(struct task_struct *tsk)
         * We use GFP_ATOMIC here because we might be doing this 
         * in the context of the idle thread */
        if (context->in_syscall && context->auditable)
-               audit_log_exit(context, GFP_ATOMIC);
+               audit_log_exit(context, tsk, GFP_ATOMIC);
 
        audit_free_context(context);
 }
@@ -839,7 +839,7 @@ void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code)
                goto out;
 
        if (context->in_syscall && context->auditable)
-               audit_log_exit(context, GFP_KERNEL);
+               audit_log_exit(context, tsk, GFP_KERNEL);
 
        context->in_syscall = 0;
        context->auditable  = 0;