Commit f5561964 authored by David Woodhouse's avatar David Woodhouse
Browse files

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: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 582edda5

kernel/auditsc.c

+8 −5
Original line number Diff line number Diff line
@@ -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 @@ static void audit_log_task_info(struct audit_buffer *ab) 
	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 @@ void audit_free(struct task_struct *tsk) 
		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 @@ void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code) 
		return;



	if (context->in_syscall && context->auditable)

		audit_log_exit(context);

		audit_log_exit(context, GFP_KERNEL);



	context->in_syscall = 0;

	context->auditable  = 0;