AUDIT: Avoid scheduling in idle thread
When we flush a pending syscall audit record due to audit_free(), we
might be doing that in the context of the idle thread. So use GFP_ATOMIC
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 86d91fe..517b253 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -41,6 +41,7 @@
#include <linux/time.h>
#include <linux/kthread.h>
#include <linux/netlink.h>
+#include <linux/compiler.h>
#include <asm/unistd.h>
/* 0 = no checking
@@ -778,13 +779,13 @@
up_read(&mm->mmap_sem);
}
-static void audit_log_exit(struct audit_context *context)
+static void audit_log_exit(struct audit_context *context, unsigned int gfp_mask)
{
int i;
struct audit_buffer *ab;
struct audit_aux_data *aux;
- ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL);
+ ab = audit_log_start(context, gfp_mask, AUDIT_SYSCALL);
if (!ab)
return; /* audit_panic has been called */
audit_log_format(ab, "arch=%x syscall=%d",
@@ -900,9 +901,11 @@
return;
/* Check for system calls that do not go through the exit
- * function (e.g., exit_group), then free context block. */
+ * function (e.g., exit_group), then free context block.
+ * 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);
+ audit_log_exit(context, GFP_ATOMIC);
audit_free_context(context);
}
@@ -1007,7 +1010,7 @@
return;
if (context->in_syscall && context->auditable)
- audit_log_exit(context);
+ audit_log_exit(context, GFP_KERNEL);
context->in_syscall = 0;
context->auditable = 0;