From 4c737b41de7f4eef2a593803bad1b918dd718b10 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 10 Aug 2016 11:23:44 -0400 Subject: cgroup: make cgroup_path() and friends behave in the style of strlcpy() cgroup_path() and friends used to format the path from the end and thus the resulting path usually didn't start at the start of the passed in buffer. Also, when the buffer was too small, the partial result was truncated from the head rather than tail and there was no way to tell how long the full path would be. These make the functions less robust and more awkward to use. With recent updates to kernfs_path(), cgroup_path() and friends can be made to behave in strlcpy() style. * cgroup_path(), cgroup_path_ns[_locked]() and task_cgroup_path() now always return the length of the full path. If buffer is too small, it contains nul terminated truncated output. * All users updated accordingly. v2: cgroup_path() usage in kernel/sched/debug.c converted. Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Cc: Serge Hallyn Cc: Peter Zijlstra --- kernel/cpuset.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/cpuset.c') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index c7fd2778ed50..793ae6fd96dc 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2689,7 +2689,7 @@ void __cpuset_memory_pressure_bump(void) int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *tsk) { - char *buf, *p; + char *buf; struct cgroup_subsys_state *css; int retval; @@ -2700,18 +2700,18 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, retval = -ENAMETOOLONG; css = task_get_css(tsk, cpuset_cgrp_id); - p = cgroup_path_ns(css->cgroup, buf, PATH_MAX, - current->nsproxy->cgroup_ns); + retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX, + current->nsproxy->cgroup_ns); css_put(css); - if (!p) + if (retval >= PATH_MAX) goto out_free; - seq_puts(m, p); + seq_puts(m, buf); seq_putc(m, '\n'); retval = 0; out_free: kfree(buf); out: - return retval; + return 0; } #endif /* CONFIG_PROC_PID_CPUSET */ -- cgit v1.2.3-70-g09d2 From 679a5e3f12830392d14f94b04bbe0f3cabdbd773 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 29 Sep 2016 11:58:36 +0200 Subject: cpuset: fix error handling regression in proc_cpuset_show() 4c737b41de7f ("cgroup: make cgroup_path() and friends behave in the style of strlcpy()") botched the conversion of proc_cpuset_show() and broke its error handling. It made the function return 0 on failures and fail to handle error returns from cgroup_path_ns(). Fix it. Reported-by: Dan Carpenter Signed-off-by: Tejun Heo --- kernel/cpuset.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel/cpuset.c') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 793ae6fd96dc..97dd8e178786 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2698,12 +2698,13 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, if (!buf) goto out; - retval = -ENAMETOOLONG; css = task_get_css(tsk, cpuset_cgrp_id); retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX, current->nsproxy->cgroup_ns); css_put(css); if (retval >= PATH_MAX) + retval = -ENAMETOOLONG; + if (retval < 0) goto out_free; seq_puts(m, buf); seq_putc(m, '\n'); @@ -2711,7 +2712,7 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, out_free: kfree(buf); out: - return 0; + return retval; } #endif /* CONFIG_PROC_PID_CPUSET */ -- cgit v1.2.3-70-g09d2