This is a note to let you know that I've just added the patch titled
Subject:[PATCH 2/5] eventfs: Remove "is_freed" union with rcu head
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
eventfs-remove-is_freed-union-with-rcu-head.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable-owner@xxxxxxxxxxxxxxx Sun Nov 5 17:01:44 2023
From: Steven Rostedt <rostedt@xxxxxxxxxxx>
Date: Sun, 05 Nov 2023 10:56:32 -0500
Subject:[PATCH 2/5] eventfs: Remove "is_freed" union with rcu head
To: linux-kernel@xxxxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx, <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>, Mark Rutland <mark.rutland@xxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Ajay Kaher <akaher@xxxxxxxxxx>
Message-ID: <20231105160139.498444992@xxxxxxxxxxx>
From: Steven Rostedt <rostedt@xxxxxxxxxxx>
From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
commit f2f496370afcbc5227d7002da28c74b91fed12ff upstream
The eventfs_inode->is_freed was a union with the rcu_head with the
assumption that when it was on the srcu list the head would contain a
pointer which would make "is_freed" true. But that was a wrong assumption
as the rcu head is a single link list where the last element is NULL.
Instead, split the nr_entries integer so that "is_freed" is one bit and
the nr_entries is the next 31 bits. As there shouldn't be more than 10
(currently there's at most 5 to 7 depending on the config), this should
not be a problem.
Link: https://lkml.kernel.org/r/20231101172649.049758712@xxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ajay Kaher <akaher@xxxxxxxxxx>
Fixes: 63940449555e7 ("eventfs: Implement eventfs lookup, read, open functions")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/tracefs/event_inode.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -38,6 +38,7 @@ struct eventfs_inode {
* @fop: file_operations for file or directory
* @iop: inode_operations for file or directory
* @data: something that the caller will want to get to later on
+ * @is_freed: Flag set if the eventfs is on its way to be freed
* @mode: the permission that the file or directory should have
*/
struct eventfs_file {
@@ -52,15 +53,14 @@ struct eventfs_file {
* Union - used for deletion
* @del_list: list of eventfs_file to delete
* @rcu: eventfs_file to delete in RCU
- * @is_freed: node is freed if one of the above is set
*/
union {
struct list_head del_list;
struct rcu_head rcu;
- unsigned long is_freed;
};
void *data;
- umode_t mode;
+ unsigned int is_freed:1;
+ unsigned int mode:31;
};
static DEFINE_MUTEX(eventfs_mutex);
@@ -814,6 +814,8 @@ static void eventfs_remove_rec(struct ev
}
}
+ ef->is_freed = 1;
+
list_del_rcu(&ef->list);
list_add_tail(&ef->del_list, head);
}
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-6.6/eventfs-use-simple_recursive_removal-to-clean-up-dentries.patch
queue-6.6/eventfs-delete-eventfs_inode-when-the-last-dentry-is-freed.patch
queue-6.6/eventfs-save-ownership-and-mode.patch
queue-6.6/tracing-have-trace_event_file-have-ref-counters.patch
queue-6.6/eventfs-remove-is_freed-union-with-rcu-head.patch
