diff options
| author | Beau Belgrave <beaub@linux.microsoft.com> | 2023-06-01 15:49:28 -0700 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-06-14 12:41:53 -0400 |
| commit | ed0e0ae0c932188654422d01f4e0ea14ff97c063 (patch) | |
| tree | 7c444b397cc86a62be6b45142b490f5556c6544e | |
| parent | 42187bdc3ca45435bec96c66a90276315b2db1cb (diff) | |
| download | linux-ed0e0ae0c932188654422d01f4e0ea14ff97c063.tar.gz | |
tracing/user_events: Remove user_ns walk for groups
During discussions it was suggested that user_ns is not a good place to
try to attach a tracing namespace. The current code has stubs to enable
that work that are very likely to change and incur a performance cost.
Remove the user_ns walk when creating a group and determining the system
name to use, since it's unlikely user_ns will be used in the future.
Link: https://lore.kernel.org/all/20230601-urenkel-holzofen-cd9403b9cadd@brauner/
Link: https://lore.kernel.org/linux-trace-kernel/20230601224928.301-1-beaub@linux.microsoft.com
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/trace_events_user.c | 42 |
1 files changed, 5 insertions, 37 deletions
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 49914b6cb6517b..cf6d4c02c363c8 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -182,21 +182,11 @@ static void user_event_group_destroy(struct user_event_group *group) kfree(group); } -static char *user_event_group_system_name(struct user_namespace *user_ns) +static char *user_event_group_system_name(void) { char *system_name; int len = sizeof(USER_EVENTS_SYSTEM) + 1; - if (user_ns != &init_user_ns) { - /* - * Unexpected at this point: - * We only currently support init_user_ns. - * When we enable more, this will trigger a failure so log. - */ - pr_warn("user_events: Namespace other than init_user_ns!\n"); - return NULL; - } - system_name = kmalloc(len, GFP_KERNEL); if (!system_name) @@ -207,34 +197,12 @@ static char *user_event_group_system_name(struct user_namespace *user_ns) return system_name; } -static inline struct user_event_group -*user_event_group_from_user_ns(struct user_namespace *user_ns) -{ - if (user_ns == &init_user_ns) - return init_group; - - return NULL; -} - static struct user_event_group *current_user_event_group(void) { - struct user_namespace *user_ns = current_user_ns(); - struct user_event_group *group = NULL; - - while (user_ns) { - group = user_event_group_from_user_ns(user_ns); - - if (group) - break; - - user_ns = user_ns->parent; - } - - return group; + return init_group; } -static struct user_event_group -*user_event_group_create(struct user_namespace *user_ns) +static struct user_event_group *user_event_group_create(void) { struct user_event_group *group; @@ -243,7 +211,7 @@ static struct user_event_group if (!group) return NULL; - group->system_name = user_event_group_system_name(user_ns); + group->system_name = user_event_group_system_name(); if (!group->system_name) goto error; @@ -2603,7 +2571,7 @@ static int __init trace_events_user_init(void) if (!fault_cache) return -ENOMEM; - init_group = user_event_group_create(&init_user_ns); + init_group = user_event_group_create(); if (!init_group) { kmem_cache_destroy(fault_cache); |