Commit 6db12ee0 authored by Josh Hunt's avatar Josh Hunt Committed by Peter Zijlstra
Browse files

psi: allow unprivileged users with CAP_SYS_RESOURCE to write psi files 



Currently only root can write files under /proc/pressure. Relax this to
allow tasks running as unprivileged users with CAP_SYS_RESOURCE to be
able to write to these files.

Signed-off-by: default avatarJosh Hunt <johunt@akamai.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210402025833.27599-1-johunt@akamai.com
parent 0a2b65c0

kernel/sched/psi.c

+14 −6
Original line number Diff line number Diff line
@@ -1061,19 +1061,27 @@ static int psi_cpu_show(struct seq_file *m, void *v) 
	return psi_show(m, &psi_system, PSI_CPU);

}



static int psi_open(struct file *file, int (*psi_show)(struct seq_file *, void *))

{

	if (file->f_mode & FMODE_WRITE && !capable(CAP_SYS_RESOURCE))

		return -EPERM;



	return single_open(file, psi_show, NULL);

}



static int psi_io_open(struct inode *inode, struct file *file)

{

	return single_open(file, psi_io_show, NULL);

	return psi_open(file, psi_io_show);

}



static int psi_memory_open(struct inode *inode, struct file *file)

{

	return single_open(file, psi_memory_show, NULL);

	return psi_open(file, psi_memory_show);

}



static int psi_cpu_open(struct inode *inode, struct file *file)

{

	return single_open(file, psi_cpu_show, NULL);

	return psi_open(file, psi_cpu_show);

}



struct psi_trigger *psi_trigger_create(struct psi_group *group,
@@ -1353,9 +1361,9 @@ static int __init psi_proc_init(void) 
{

	if (psi_enable) {

		proc_mkdir("pressure", NULL);

		proc_create("pressure/io", 0, NULL, &psi_io_proc_ops);

		proc_create("pressure/memory", 0, NULL, &psi_memory_proc_ops);

		proc_create("pressure/cpu", 0, NULL, &psi_cpu_proc_ops);

		proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops);

		proc_create("pressure/memory", 0666, NULL, &psi_memory_proc_ops);

		proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops);

	}

	return 0;

}