[dm-devel] [PATCH V2] libmultipath: free pp if store_path fails in disassemble_map
Martin Wilck
mwilck at suse.com
Mon Aug 10 12:20:27 UTC 2020
Hello Liu,
On Fri, 2020-07-24 at 09:40 +0800, Zhiqiang Liu wrote:
> In disassemble_map func, one pp will be allocated and stored in
> pgp->paths. However, if store_path fails, pp will not be freed,
> then memory leak problem occurs.
>
> Here, we will call free_path to free pp when store_path fails.
>
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26 at huawei.com>
> Signed-off-by: lixiaokeng <lixiaokeng at huawei.com>
> ---
> V1->V2: update based on ups/submit-2007 branch.
>
> libmultipath/dmparser.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
thanks for the patch. I'd suggest to do this without the pp_alloc_flag
variable, by pulling the store_path() call into the if (!pp)
conditional and treating failure differently in both branches of the
conditional. (Side note: if we introduce a boolean like this, we should
use "bool" as the variable type).
Unless you object, I'll add that change on top of my submit-2007
series, giving you appropriate credits.
@Ben, @Christophe: I've been considering for some time to start
handling cases like this with __attribute__((cleanup(f)))) (
https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html).
That could reduce the amount of goto clauses for error handling
significantly. It would be a major change in coding style though. What
do you think?
Regards,
Martin
> diff --git a/libmultipath/dmparser.c b/libmultipath/dmparser.c
> index b9858fa5..8a0501ba 100644
> --- a/libmultipath/dmparser.c
> +++ b/libmultipath/dmparser.c
> @@ -143,6 +143,7 @@ int disassemble_map(const struct _vector
> *pathvec,
> int def_minio = 0;
> struct path * pp;
> struct pathgroup * pgp;
> + int pp_alloc_flag = 0;
>
> assert(pathvec != NULL);
> p = params;
> @@ -292,6 +293,7 @@ int disassemble_map(const struct _vector
> *pathvec,
>
> for (j = 0; j < num_paths; j++) {
> pp = NULL;
> + pp_alloc_flag = 0;
> p += get_word(p, &word);
>
> if (!word)
> @@ -304,13 +306,16 @@ int disassemble_map(const struct _vector
> *pathvec,
>
> if (!pp)
> goto out1;
> -
> + pp_alloc_flag = 1;
> strlcpy(pp->dev_t, word, BLK_DEV_SIZE);
> }
> FREE(word);
>
> - if (store_path(pgp->paths, pp))
> + if (store_path(pgp->paths, pp)) {
> + if (pp_alloc_flag)
> + free_path(pp);
> goto out;
> + }
>
> pgp->id ^= (long)pp;
> pp->pgindex = i + 1;
More information about the dm-devel
mailing list