[lkml]   [2007]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] sysfs: kill an extra put in sysfs_create_link() failure path
Hi Tejun,

Thanks for tracking this down and fixing it.

On 7/18/07, Tejun Heo <> wrote:
> There is a subtle bug in sysfs_create_link() failure path. When
> symlink creation fails because there's already a node with the same
> name, the target sysfs_dirent is put twice - once by failure path of
> sysfs_create_link() and once more when the symlink is released.

The "symlink" is released? But the creation of the symlink is
precisely what failed here ... did it not?

> Fix it by making only the symlink node responsible for putting
> target_sd.

And again ... the changelog sounds confusing indeed, perhaps I'm
not familiar enough with sysfs symlink-related terminology/semantics.
Care to elaborate?

> sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
> if (!sd)
> goto out_put;
> +
> sd->s_elem.symlink.target_sd = target_sd;
> + target_sd = NULL; /* reference is now owned by the symlink */

Wow. This looks like a very mysterious way to fix a mysterious bug :-)
BTW I just looked over at sysfs_create_link() and ... it looks quite ...
unnecessarily complicated/obfuscated ...

Thanks again,
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-07-18 16:51    [W:0.132 / U:0.276 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site