[Devel] [PATCH v2] ub: correct _ub_get_css() retvalue for dying/stopped containers
Vasily Averin
vvs at virtuozzo.com
Tue Sep 14 00:52:54 MSK 2021
Currently __ub_get_css(ub) for dying or stopped container returns
ub0-related css as failback. As result read from /proc/bc/<>/ files
can show ve0-related info.
With this patch, __ub_get_css() will return NULL in such cases,
and everyone who called of this function now handles this return value.
https://jira.sw.ru/browse/PSBM-123686
Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
---
v2: removed an extra cehck in end of __ub_get_css(), thanks to eshatokhin@
include/bc/beancounter.h | 10 +++++++-
kernel/bc/beancounter.c | 65 +++++++++++++++++++++++++++++++++++-------------
kernel/bc/io_prio.c | 13 ++++++++--
kernel/bc/proc.c | 3 +++
kernel/bc/vm_pages.c | 18 +++++++++++---
5 files changed, 85 insertions(+), 24 deletions(-)
diff --git a/include/bc/beancounter.h b/include/bc/beancounter.h
index e4c5017..4b69a34 100644
--- a/include/bc/beancounter.h
+++ b/include/bc/beancounter.h
@@ -163,6 +163,10 @@ static __always_inline struct cgroup_subsys_state *__ub_get_css(struct user_bean
css = ACCESS_ONCE(ub->ub_bound_css[idx]);
if (likely(css && css_tryget(css))) {
rcu_read_unlock();
+ if ((ub != &ub0) && (css == ub0.ub_bound_css[idx])) {
+ css_put(css);
+ css = NULL;
+ }
return css;
}
@@ -183,7 +187,11 @@ static __always_inline struct cgroup_subsys_state *__ub_get_css(struct user_bean
if (css)
css_put(css);
- css_get(root_css);
+ if (ub == &ub0)
+ css_get(root_css);
+ else
+ root_css = NULL;
+
return root_css;
}
diff --git a/kernel/bc/beancounter.c b/kernel/bc/beancounter.c
index 5e04d6c..ae8d21a 100644
--- a/kernel/bc/beancounter.c
+++ b/kernel/bc/beancounter.c
@@ -117,33 +117,53 @@ int ub_attach_task(struct user_beancounter *ub, struct task_struct *tsk)
{
int ret = 0;
struct user_beancounter *old_ub = tsk->task_bc.exec_ub;
- struct cgroup_subsys_state *css;
+ struct cgroup_subsys_state *css, *com, *cob;
if (ub == old_ub)
goto out;
+
+ ret = -ENODEV;
+ com = ub_get_mem_css(old_ub);
+ if (!com)
+ goto out;
+
+ cob = ub_get_blkio_css(old_ub);
+ if (!cob)
+ goto fail_om;
+
css = ub_get_mem_css(ub);
+ if (!css)
+ goto fail_ob;
+
ret = cgroup_kernel_attach(css->cgroup, tsk);
css_put(css);
if (ret)
- goto out;
+ goto fail_ob;
+
+ ret = -ENODEV;
css = ub_get_blkio_css(ub);
+ if (!css)
+ goto fail_blkio;
+
ret = cgroup_kernel_attach(css->cgroup, tsk);
css_put(css);
if (ret)
goto fail_blkio;
+
ret = cgroup_kernel_attach(ub->css.cgroup, tsk);
if (ret)
goto fail_ub;
+
+fail_ob:
+ css_put(cob);
+fail_om:
+ css_put(com);
out:
return ret;
fail_ub:
- css = ub_get_blkio_css(old_ub);
- cgroup_kernel_attach(css->cgroup, tsk);
- css_put(css);
+ cgroup_kernel_attach(cob->cgroup, tsk);
fail_blkio:
- css = ub_get_mem_css(old_ub);
- cgroup_kernel_attach(css->cgroup, tsk);
- css_put(css);
+ cgroup_kernel_attach(com->cgroup, tsk);
goto out;
}
@@ -167,6 +187,9 @@ int ub_update_memcg(struct user_beancounter *ub)
int ret;
css = ub_get_mem_css(ub);
+ if (!css)
+ return -ENODEV;
+
ret = mem_cgroup_apply_beancounter(mem_cgroup_from_cont(css->cgroup),
ub);
css_put(css);
@@ -181,8 +204,10 @@ void ub_sync_pids(struct user_beancounter *ub)
struct cgroup_subsys_state *css;
css = ub_get_pids_css(ub);
- pids_cgroup_sync_beancounter(pids_cgroup_from_cont(css->cgroup), ub);
- css_put(css);
+ if (css) {
+ pids_cgroup_sync_beancounter(pids_cgroup_from_cont(css->cgroup), ub);
+ css_put(css);
+ }
}
/*
@@ -193,18 +218,22 @@ void ub_sync_memcg(struct user_beancounter *ub)
struct cgroup_subsys_state *css;
css = ub_get_mem_css(ub);
- mem_cgroup_sync_beancounter(mem_cgroup_from_cont(css->cgroup), ub);
- css_put(css);
+ if (css) {
+ mem_cgroup_sync_beancounter(mem_cgroup_from_cont(css->cgroup), ub);
+ css_put(css);
+ }
}
unsigned long ub_total_pages(struct user_beancounter *ub, bool swap)
{
struct cgroup_subsys_state *css;
- unsigned long ret;
+ unsigned long ret = 0;
css = ub_get_mem_css(ub);
- ret = mem_cgroup_total_pages(mem_cgroup_from_cont(css->cgroup), swap);
- css_put(css);
+ if (css) {
+ ret = mem_cgroup_total_pages(mem_cgroup_from_cont(css->cgroup), swap);
+ css_put(css);
+ }
return ret;
}
@@ -576,11 +605,12 @@ static ssize_t ub_cgroup_read(struct cgroup *cg, struct cftype *cft,
struct cgroup_subsys_state *bound_css;
char *path;
int len;
- ssize_t ret;
+ ssize_t ret = -ENOMEM;
bound_css = __ub_get_css(ub, cft->private);
+ if (!bound_css)
+ goto fail;
- ret = -ENOMEM;
path = kmalloc(PATH_MAX + 1, GFP_KERNEL);
if (!path)
goto out;
@@ -594,6 +624,7 @@ static ssize_t ub_cgroup_read(struct cgroup *cg, struct cftype *cft,
kfree(path);
out:
css_put(bound_css);
+fail:
return ret;
}
diff --git a/kernel/bc/io_prio.c b/kernel/bc/io_prio.c
index 16f5024..01a6251 100644
--- a/kernel/bc/io_prio.c
+++ b/kernel/bc/io_prio.c
@@ -35,8 +35,12 @@ int ub_set_ioprio(int id, int ioprio)
goto out;
css = ub_get_blkio_css(ub);
+ if (!css)
+ goto put;
+
ret = blkcg_set_weight(css->cgroup, ioprio_weight[ioprio]);
css_put(css);
+put:
put_beancounter(ub);
out:
return ret;
@@ -59,8 +63,10 @@ static int bc_iostat(struct seq_file *f, struct user_beancounter *bc)
__ub_percpu_sum(bc, fuse_bytes) >> 9);
css = ub_get_blkio_css(bc);
- blkcg_show_ub_iostat(css->cgroup, f);
- css_put(css);
+ if (css) {
+ blkcg_show_ub_iostat(css->cgroup, f);
+ css_put(css);
+ }
return 0;
}
@@ -146,6 +152,9 @@ static int bc_ioprio_show(struct seq_file *f, void *v)
bc = seq_beancounter(f);
css = ub_get_blkio_css(bc);
+ if (!css)
+ return 0;
+
weight = blkcg_get_weight(css->cgroup);
css_put(css);
diff --git a/kernel/bc/proc.c b/kernel/bc/proc.c
index efcfdbc..2251d6d 100644
--- a/kernel/bc/proc.c
+++ b/kernel/bc/proc.c
@@ -144,6 +144,9 @@ static int bc_proc_nodeinfo_show(struct seq_file *f, void *v)
unsigned long pages[NR_LRU_LISTS];
css = ub_get_mem_css(seq_beancounter(f));
+ if (!css)
+ return 0;
+
for_each_node_state(nid, N_HIGH_MEMORY) {
memset(pages, 0, sizeof(pages));
mem_cgroup_get_nr_pages(mem_cgroup_from_cont(css->cgroup),
diff --git a/kernel/bc/vm_pages.c b/kernel/bc/vm_pages.c
index e5019c0..7952da1 100644
--- a/kernel/bc/vm_pages.c
+++ b/kernel/bc/vm_pages.c
@@ -127,7 +127,7 @@ int ub_enough_memory(struct mm_struct *mm, long pages)
struct user_beancounter *ub;
struct cgroup_subsys_state *css;
unsigned long flags;
- int ret;
+ int ret = -ENOMEM;
if (!mm)
return 0;
@@ -135,15 +135,16 @@ int ub_enough_memory(struct mm_struct *mm, long pages)
ub = mm->mm_ub;
if (ub->ub_parms[UB_PRIVVMPAGES].held >
- ub->ub_parms[UB_PRIVVMPAGES].barrier) {
- ret = -ENOMEM;
+ ub->ub_parms[UB_PRIVVMPAGES].barrier)
goto out;
- }
if (ub == get_ub0() || ub_overcommit_memory)
return 0;
css = ub_get_mem_css(ub);
+ if (!css)
+ goto out;
+
ret = mem_cgroup_enough_memory(mem_cgroup_from_cont(css->cgroup), pages);
css_put(css);
out:
@@ -166,6 +167,9 @@ static int bc_fill_sysinfo(struct user_beancounter *ub,
return NOTIFY_DONE | NOTIFY_STOP_MASK;
css = ub_get_mem_css(ub);
+ if (!css)
+ return NOTIFY_BAD;
+
mem_cgroup_fill_sysinfo(mem_cgroup_from_cont(css->cgroup), si);
css_put(css);
@@ -185,6 +189,9 @@ static int bc_fill_meminfo(struct user_beancounter *ub,
goto out;
css = ub_get_mem_css(ub);
+ if (!css)
+ return NOTIFY_BAD;
+
mem_cgroup_fill_meminfo(mem_cgroup_from_cont(css->cgroup), mi);
css_put(css);
@@ -213,6 +220,9 @@ static int bc_fill_vmstat(struct user_beancounter *ub, unsigned long *stat)
return NOTIFY_OK;
css = ub_get_mem_css(ub);
+ if (!css)
+ return NOTIFY_BAD;
+
mem_cgroup_fill_vmstat(mem_cgroup_from_cont(css->cgroup), stat);
css_put(css);
return NOTIFY_OK;
--
1.8.3.1
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