Commit ce625a80 authored by David Woodhouse's avatar David Woodhouse
Browse files

AUDIT: Reduce contention in audit_serial() 


... by generating serial numbers only if an audit context is actually
_used_, rather than doing so at syscall entry even when the context
isn't necessarily marked auditable.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent d5b454f2

kernel/audit.c

+3 −1
Original line number Diff line number Diff line
@@ -625,7 +625,9 @@ unsigned int audit_serial(void) 
	unsigned int ret;



	spin_lock_irqsave(&serial_lock, flags);

	ret = serial++;

	do {

		ret = ++serial;

	} while (unlikely(!ret));

	spin_unlock_irqrestore(&serial_lock, flags);



	return ret;

kernel/auditsc.c

+3 −1
Original line number Diff line number Diff line
@@ -984,7 +984,7 @@ void audit_syscall_entry(struct task_struct *tsk, int arch, int major, 
	if (likely(state == AUDIT_DISABLED))

		return;



	context->serial     = audit_serial();

	context->serial     = 0;

	context->ctime      = CURRENT_TIME;

	context->in_syscall = 1;

	context->auditable  = !!(state == AUDIT_RECORD_CONTEXT);
@@ -1138,6 +1138,8 @@ void audit_inode(const char *name, const struct inode *inode, unsigned flags) 
void auditsc_get_stamp(struct audit_context *ctx,

		       struct timespec *t, unsigned int *serial)

{

	if (!ctx->serial)

		ctx->serial = audit_serial();

	t->tv_sec  = ctx->ctime.tv_sec;

	t->tv_nsec = ctx->ctime.tv_nsec;

	*serial    = ctx->serial;