From: Denis Efremov <efremov@linux.com>
To: Julia Lawall <julia.lawall@inria.fr>
Cc: cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6] coccinelle: api: add kvfree script
Date: Mon, 3 Aug 2020 14:33:45 +0300 [thread overview]
Message-ID: <a8d8eade-1d98-b8d9-7c66-bd05b22af751@linux.com> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2008022142550.2531@hadrien>
On 8/2/20 11:24 PM, Julia Lawall wrote:
>> +@initialize:python@
>> +@@
>> +# low-level memory api
>> +filter = frozenset(['__vmalloc_area_node'])
>> +
>> +def relevant(p):
>> + return not (filter & {el.current_element for el in p})
>
> Is this used?
I'll remove it in v8. Or do you want me to add iterate_dir_item() in the list?
>
> Otherwise, I think it would be good to not warn about a use of kvfree
> if that use is reachable from a kvmalloc. There seems to be such a false
> positive in fs/btrfs/send.c, on line 1118.
I don't know how to handle this case without position filter.
It's too complex. In iterate_dir_item() there is:
buf = kmalloc(buf_len, GFP_KERNEL);
while(...) {
if (...) {
if (is_vmalloc_addr(buf)) {
vfree(buf);
...
} else {
char *tmp = krealloc(buf, ...);
if (!tmp)
kfree(buf);
...
}
if (!buf) {
buf = kvmalloc(buf_len, GFP_KERNEL);
...
}
}
}
kvfree(buf);
Adding "when != kvfree(E)" is not enough:
* E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
* kvmalloc_array\)(...)@k
... when != is_vmalloc_addr(E)
+ when != kvfree(E)
when any
* \(kfree\|kzfree\|vfree\|vfree_atomic\)(E)@p
>
> It also seems that when there are both a kmalloc and a vmalloc, there is
> no warning if kfree or vfree is used. Is that intentional?
>
No, I will try to address it in v8.
Regards,
Denis
next prev parent reply other threads:[~2020-08-03 11:33 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-05 20:42 [PATCH] coccinelle: api: add kvfree script Denis Efremov
2020-06-05 20:51 ` [Cocci] " Julia Lawall
2020-06-05 21:15 ` Denis Efremov
2020-06-05 21:19 ` Julia Lawall
2020-06-14 9:03 ` Denis Efremov
2020-06-14 9:17 ` Julia Lawall
2020-06-14 9:24 ` Denis Efremov
2020-06-14 18:36 ` [PATCH v2] " Denis Efremov
2020-07-17 12:00 ` Denis Efremov
2020-07-30 14:01 ` [PATCH v3] " Denis Efremov
2020-07-30 14:05 ` Denis Efremov
2020-07-30 14:07 ` [PATCH v4] " Denis Efremov
2020-07-30 20:15 ` Julia Lawall
2020-07-30 20:38 ` Julia Lawall
2020-07-31 8:31 ` Denis Efremov
2020-07-31 8:48 ` Julia Lawall
2020-07-31 10:47 ` [PATCH v5] " Denis Efremov
2020-07-31 21:00 ` [PATCH v6] " Denis Efremov
2020-08-02 20:24 ` Julia Lawall
2020-08-03 11:33 ` Denis Efremov [this message]
2020-08-03 12:18 ` Julia Lawall
2020-08-03 11:45 ` Denis Efremov
2020-08-03 12:12 ` Julia Lawall
2020-08-03 18:34 ` [PATCH v7] coccinelle: api: add kfree_mismatch script Denis Efremov
2020-09-21 17:15 ` Denis Efremov
2020-10-15 20:48 ` Julia Lawall
2020-10-16 8:54 ` [PATCH v8] " Denis Efremov
2020-10-17 21:17 ` [Cocci] " Julia Lawall
[not found] <3aea12cf-68dc-e140-936f-cfefb2adbc8f@web.de>
2020-08-02 7:09 ` [PATCH v6] coccinelle: api: add kvfree script Julia Lawall
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