Commit f0de53bb authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[PATCH] x86_64: Remove excessive stack allocation in MCE code with large NR_CPUS 



Remove excessive stack allocation in MCE code with large NR_CPUS

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 94ad8474

arch/x86_64/kernel/mce.c

+7 −1
Original line number Diff line number Diff line
@@ -379,18 +379,23 @@ static void collect_tscs(void *data) 


static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff_t *off)

{

	unsigned long cpu_tsc[NR_CPUS];

	unsigned long *cpu_tsc;

	static DECLARE_MUTEX(mce_read_sem);

	unsigned next;

	char __user *buf = ubuf;

	int i, err;



	cpu_tsc = kmalloc(NR_CPUS * sizeof(long), GFP_KERNEL);

	if (!cpu_tsc)

		return -ENOMEM;



	down(&mce_read_sem); 

	next = rcu_dereference(mcelog.next);



	/* Only supports full reads right now */

	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) { 

		up(&mce_read_sem);

		kfree(cpu_tsc);

		return -EINVAL;

	}
@@ -421,6 +426,7 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff 
		}

	} 	

	up(&mce_read_sem);

	kfree(cpu_tsc);

	return err ? -EFAULT : buf - ubuf; 

}