lkml.org 
[lkml]   [2022]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 1/2] tracing/user_events: Use remote writes for event enablement
Hi,

I have some comments.

On Thu, 27 Oct 2022 15:40:10 -0700
Beau Belgrave <beaub@linux.microsoft.com> wrote:

[...]
> @@ -1570,11 +1610,12 @@ static long user_reg_get(struct user_reg __user *ureg, struct user_reg *kreg)
> * Registers a user_event on behalf of a user process.
> */
> static long user_events_ioctl_reg(struct user_event_file_info *info,
> - unsigned long uarg)
> + struct file *file, unsigned long uarg)
> {
> struct user_reg __user *ureg = (struct user_reg __user *)uarg;
> struct user_reg reg;
> struct user_event *user;
> + struct user_event_enabler *enabler;
> char *name;
> long ret;
>
> @@ -1607,8 +1648,12 @@ static long user_events_ioctl_reg(struct user_event_file_info *info,
> if (ret < 0)
> return ret;
>
> + enabler = user_event_enabler_create(file, &reg, user);
> +
> + if (!enabler)

Shouldn't we free the user_event if needed here?
(I found the similar memory leak pattern in the above failure case
of the user_events_ref_add().)

> + return -ENOMEM;
> +
> put_user((u32)ret, &ureg->write_index);
> - put_user(user->index, &ureg->status_bit);
>
> return 0;
> }
[...]
> @@ -1849,7 +1863,6 @@ static int user_status_open(struct inode *node, struct file *file)
>
> static const struct file_operations user_status_fops = {
> .open = user_status_open,
> - .mmap = user_status_mmap,

So, if this drops the mmap operation, can we drop the writable flag from
the status tracefs file?

static int create_user_tracefs(void)
{
[...]
/* mmap with MAP_SHARED requires writable fd */
emmap = tracefs_create_file("user_events_status", TRACE_MODE_WRITE,
NULL, NULL, &user_status_fops);

Thank you,

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>

\
 
 \ /
  Last update: 2022-10-31 15:48    [W:0.139 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site