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Commit 648f2ac6 by Christian Brauner Committed by Stéphane Graber
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cgfs: explicitly check for NULL

Somehow this implementation of a cgroupfs backend decided to use the hierarchy numbers it detects in /proc/cgroups and /proc/self/cgroups as indices for the hierarchy struct. Controller numbering usually starts at 1 but may start at 0 if: a) the controller is not mounted on a cgroups v1 hierarchy; b) the controller is bound to the cgroups v2 single unified hierarchy; or c) the controller is disabled To avoid having to rework our fallback backend significantly, we should explicitly check for each controller if hierarchy[i] != NULL. Signed-off-by: 's avatarChristian Brauner <christian.brauner@canonical.com>
parent 20aa5993
Showing with 22 additions and 1 deletion
src/lxc/cgfs.c
...@@ -495,7 +495,7 @@ static bool find_hierarchy_mountpts( struct cgroup_meta_data *meta_data, char ** ...@@ -495,7 +495,7 @@ static bool find_hierarchy_mountpts( struct cgroup_meta_data *meta_data, char **
goto out; goto out;
h = NULL; h = NULL;
for (k = 1; k <= meta_data->maximum_hierarchy; k++) { for (k = 0; k <= meta_data->maximum_hierarchy; k++) {
if (meta_data->hierarchies[k] && if (meta_data->hierarchies[k] &&
meta_data->hierarchies[k]->subsystems[0] && meta_data->hierarchies[k]->subsystems[0] &&
lxc_string_in_array(meta_data->hierarchies[k]->subsystems[0], (const char **)subsystems)) { lxc_string_in_array(meta_data->hierarchies[k]->subsystems[0], (const char **)subsystems)) {
...@@ -637,6 +637,8 @@ static struct cgroup_hierarchy *lxc_cgroup_find_hierarchy(struct cgroup_meta_dat ...@@ -637,6 +637,8 @@ static struct cgroup_hierarchy *lxc_cgroup_find_hierarchy(struct cgroup_meta_dat
size_t i; size_t i;
for (i = 0; i <= meta_data->maximum_hierarchy; i++) { for (i = 0; i <= meta_data->maximum_hierarchy; i++) {
struct cgroup_hierarchy *h = meta_data->hierarchies[i]; struct cgroup_hierarchy *h = meta_data->hierarchies[i];
if (!h)
continue;
if (h && lxc_string_in_array(subsystem, (const char **)h->subsystems)) if (h && lxc_string_in_array(subsystem, (const char **)h->subsystems))
return h; return h;
} }
...@@ -864,6 +866,8 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c ...@@ -864,6 +866,8 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c
/* find mount points we can use */ /* find mount points we can use */
for (info_ptr = base_info; info_ptr; info_ptr = info_ptr->next) { for (info_ptr = base_info; info_ptr; info_ptr = info_ptr->next) {
h = info_ptr->hierarchy; h = info_ptr->hierarchy;
if (!h)
continue;
mp = lxc_cgroup_find_mount_point(h, info_ptr->cgroup_path, true); mp = lxc_cgroup_find_mount_point(h, info_ptr->cgroup_path, true);
if (!mp) { if (!mp) {
ERROR("Could not find writable mount point for cgroup hierarchy %d while trying to create cgroup.", h->index); ERROR("Could not find writable mount point for cgroup hierarchy %d while trying to create cgroup.", h->index);
...@@ -951,6 +955,9 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c ...@@ -951,6 +955,9 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c
for (i = 0, info_ptr = base_info; info_ptr; info_ptr = info_ptr->next, i++) { for (i = 0, info_ptr = base_info; info_ptr; info_ptr = info_ptr->next, i++) {
char *parts2[3]; char *parts2[3];
if (!info_ptr->hierarchy)
continue;
if (lxc_string_in_array("ns", (const char **)info_ptr->hierarchy->subsystems)) if (lxc_string_in_array("ns", (const char **)info_ptr->hierarchy->subsystems))
continue; continue;
current_entire_path = NULL; current_entire_path = NULL;
...@@ -1045,6 +1052,8 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c ...@@ -1045,6 +1052,8 @@ static struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const c
/* we're done, now update the paths */ /* we're done, now update the paths */
for (i = 0, info_ptr = base_info; info_ptr; info_ptr = info_ptr->next, i++) { for (i = 0, info_ptr = base_info; info_ptr; info_ptr = info_ptr->next, i++) {
if (!info_ptr->hierarchy)
continue;
/* ignore legacy 'ns' subsystem here, lxc_cgroup_create_legacy /* ignore legacy 'ns' subsystem here, lxc_cgroup_create_legacy
* will take care of it * will take care of it
* Since we do a continue in above loop, new_cgroup_paths[i] is * Since we do a continue in above loop, new_cgroup_paths[i] is
...@@ -1082,6 +1091,9 @@ static int lxc_cgroup_create_legacy(struct cgroup_process_info *base_info, const ...@@ -1082,6 +1091,9 @@ static int lxc_cgroup_create_legacy(struct cgroup_process_info *base_info, const
int r; int r;
for (info_ptr = base_info; info_ptr; info_ptr = info_ptr->next) { for (info_ptr = base_info; info_ptr; info_ptr = info_ptr->next) {
if (!info_ptr->hierarchy)
continue;
if (!lxc_string_in_array("ns", (const char **)info_ptr->hierarchy->subsystems)) if (!lxc_string_in_array("ns", (const char **)info_ptr->hierarchy->subsystems))
continue; continue;
/* /*
...@@ -1166,6 +1178,9 @@ static int lxc_cgroupfs_enter(struct cgroup_process_info *info, pid_t pid, bool ...@@ -1166,6 +1178,9 @@ static int lxc_cgroupfs_enter(struct cgroup_process_info *info, pid_t pid, bool
snprintf(pid_buf, 32, "%lu", (unsigned long)pid); snprintf(pid_buf, 32, "%lu", (unsigned long)pid);
for (info_ptr = info; info_ptr; info_ptr = info_ptr->next) { for (info_ptr = info; info_ptr; info_ptr = info_ptr->next) {
if (!info_ptr->hierarchy)
continue;
char *cgroup_path = (enter_sub && info_ptr->cgroup_path_sub) ? char *cgroup_path = (enter_sub && info_ptr->cgroup_path_sub) ?
info_ptr->cgroup_path_sub : info_ptr->cgroup_path_sub :
info_ptr->cgroup_path; info_ptr->cgroup_path;
...@@ -1407,6 +1422,10 @@ static bool cgroupfs_mount_cgroup(void *hdata, const char *root, int type) ...@@ -1407,6 +1422,10 @@ static bool cgroupfs_mount_cgroup(void *hdata, const char *root, int type)
for (info = base_info; info; info = info->next) { for (info = base_info; info; info = info->next) {
size_t subsystem_count, i; size_t subsystem_count, i;
struct cgroup_mount_point *mp = info->designated_mount_point; struct cgroup_mount_point *mp = info->designated_mount_point;
if (!info->hierarchy)
continue;
if (!mountpoint_is_accessible(mp)) if (!mountpoint_is_accessible(mp))
mp = lxc_cgroup_find_mount_point(info->hierarchy, info->cgroup_path, true); mp = lxc_cgroup_find_mount_point(info->hierarchy, info->cgroup_path, true);
...@@ -1887,6 +1906,8 @@ find_info_for_subsystem(struct cgroup_process_info *info, const char *subsystem) ...@@ -1887,6 +1906,8 @@ find_info_for_subsystem(struct cgroup_process_info *info, const char *subsystem)
struct cgroup_process_info *info_ptr; struct cgroup_process_info *info_ptr;
for (info_ptr = info; info_ptr; info_ptr = info_ptr->next) { for (info_ptr = info; info_ptr; info_ptr = info_ptr->next) {
struct cgroup_hierarchy *h = info_ptr->hierarchy; struct cgroup_hierarchy *h = info_ptr->hierarchy;
if (!h)
continue;
if (lxc_string_in_array(subsystem, (const char **)h->subsystems)) if (lxc_string_in_array(subsystem, (const char **)h->subsystems))
return info_ptr; return info_ptr;
} }
......
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