On 17-04-18 06:13 AM, Wolfgang Bumiller wrote:
Whether the reference count has to be decremented depends
on whether the policy was created. If TCA_ACT_COOKIE is
passed and an error occurs there, the same condition still
has to be honored.
Signed-off-by: Wolfgang Bumiller <w.bumil...@proxmox.com>
Cc: Jamal Hadi Salim <j...@mojatatu.com>
---
I did not include the Acked-bys here because I've noticed that this
is still wrong. After reading a bit more and doing more tests with
different filters I realized that the `name != NULL` case is specific
to the police filter only. For the other filters this patch here breaks
refcounting in the error case (I included it for reference only).
I'm thinking the first patch should be enough. (I've tested forcing the
other filters into the error path *without* this patch and couldn't
produce crashes or reference count problems (while with this patch
applied it was leaking reference counts on creation (which makes sense
considering tcf_hash_release is used and the ACT_P_CREATED case will
keep repeating)). (Whereas without both patches simply looking through
creating and deleting a policing filter pretty much always resulted in
crashes with various different backtraces.)
The error path for cookie failure still needs handling.
In retrospect:
I think you should leave the module_put() to the end,
it protects any unloading while the action is being
processed.
It may be worth remembering a_o->init() results and
conditionally calling tcf_hash_release() based on whether
a creation happened or not. I think your original patch had
a similar idea without the extra variable I am suggesting.
cheers,
jamal
