The following commit has been merged into the sched/core branch of tip: Commit-ID: 6db12ee0456d0e369c7b59788d46e15a56ad0294 Gitweb: https://git.kernel.org/tip/6db12ee0456d0e369c7b59788d46e15a56ad0294 Author: Josh Hunt <joh...@akamai.com> AuthorDate: Thu, 01 Apr 2021 22:58:33 -04:00 Committer: Peter Zijlstra <pet...@infradead.org> CommitterDate: Thu, 08 Apr 2021 23:09:44 +02:00
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: Josh Hunt <joh...@akamai.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Acked-by: Johannes Weiner <han...@cmpxchg.org> Link: https://lkml.kernel.org/r/20210402025833.27599-1-joh...@akamai.com --- kernel/sched/psi.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index b1b00e9..d1212f1 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -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; }
