Hi Lukasz,
On Fri, Jul 13, 2018 at 12:49 PM, Lukasz Majewski lukma@denx.de wrote:
Hi Sam,
The story of this change goes further... Just checked the reason, the bug was introduced here [1]. So we can either use my patch (which adds corresponding comment to ensure we won't "fix" it later), or the whole design of dfu_config_entities() vs dfu_free_entities() should be revised.
Lukasz, what do you think about this?
Your patch seems OK to me. I've checked all use cases and in the error path the dfu_free_entities() is called.
The patch itself is ok. What I'm trying to say, is that design of dfu_config_entities() is not very good. It allocates memory for "dfu" array, and on error it doesn't free it, relying on dfu_free_entities() to free it later. That's why Coverity reported it as a memory leak in a first place (though it was false positive of course). But such a design is not what user of the function usually expects. Better design (as for my taste) would be if dfu_config_entities() cleans up everything on error, so that even if user doesn't call dfu_free_entities() after calling dfu_config_entities() (with return on error), there is no memory leak involved. This way it would be easier to control code flow, and Coverity will be happy too.
I suggest next: let's merge this patch as is (at least it makes things work as originally intended), and if my thoughts on design make sense to you, dfu_config_entities() can be reworked in further commits. Sounds ok?
I will send v2 with improved commit message soon.
(Or have I misunderstood something) ?
[1] http://git.denx.de/?p=u-boot.git;a=commit;h=5d8fae79163e94671956c99654abf48c...
On Fri, Jul 13, 2018 at 12:52 AM, Sam Protsenko semen.protsenko@linaro.org wrote:
In case of error in dfu_config_entities(), it frees "dfu" array, which leads to "data abort" in dfu_free_entities(), which tries to free the same array (and even tries to access it from linked list first). The issue occurs e.g. when partition table on device does not match $dfu_alt_info layout:
=> dfu 0 mmc 1 list Couldn't find part #2 on mmc device #1 DFU entities configuration failed! data abortTo fix this issue, do not free "dfu" array in dfu_config_entities(). It will be freed later in dfu_free_entities().
Signed-off-by: Sam Protsenko semen.protsenko@linaro.org
drivers/dfu/dfu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c index e7c91193b9..a3c09334b7 100644 --- a/drivers/dfu/dfu.c +++ b/drivers/dfu/dfu.c @@ -462,7 +462,7 @@ int dfu_config_entities(char *env, char *interface, char *devstr) ret = dfu_fill_entity(&dfu[i], s, alt_num_cnt, interface, devstr); if (ret) {
free(dfu);
/* We will free "dfu" indfu_free_entities() */ return -1; }
-- 2.18.0
Best regards,
Lukasz Majewski
--
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