* Coverity: reclaim_high(): Error handling issues
@ 2019-10-28 23:04 coverity-bot
2019-10-29 13:13 ` Michal Hocko
0 siblings, 1 reply; 2+ messages in thread
From: coverity-bot @ 2019-10-28 23:04 UTC (permalink / raw)
To: Johannes Weiner
Cc: David S. Miller, Michal Hocko, Andrew Morton, Vladimir Davydov,
Linus Torvalds, Gustavo A. R. Silva, linux-next
Hello!
This is an experimental automated report about issues detected by Coverity
from a scan of next-20191025 as part of the linux-next weekly scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan
You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by recent commits:
f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
Coverity reported the following:
*** CID 1487368: Error handling issues (CHECKED_RETURN)
/mm/memcontrol.c: 2343 in reclaim_high()
2337 gfp_t gfp_mask)
2338 {
2339 do {
2340 if (page_counter_read(&memcg->memory) <= memcg->high)
2341 continue;
2342 memcg_memory_event(memcg, MEMCG_HIGH);
vvv CID 1487368: Error handling issues (CHECKED_RETURN)
vvv Calling "try_to_free_mem_cgroup_pages" without checking return value (as is done elsewhere 5 out of 6 times).
2343 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
2344 } while ((memcg = parent_mem_cgroup(memcg)));
2345 }
2346
2347 static void high_work_func(struct work_struct *work)
2348 {
If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include:
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487368 ("Error handling issues")
Fixes: f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
Thanks for your attention!
--
Coverity-bot
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Coverity: reclaim_high(): Error handling issues
2019-10-28 23:04 Coverity: reclaim_high(): Error handling issues coverity-bot
@ 2019-10-29 13:13 ` Michal Hocko
0 siblings, 0 replies; 2+ messages in thread
From: Michal Hocko @ 2019-10-29 13:13 UTC (permalink / raw)
To: coverity-bot
Cc: Johannes Weiner, David S. Miller, Andrew Morton,
Vladimir Davydov, Linus Torvalds, Gustavo A. R. Silva,
linux-next
On Mon 28-10-19 16:04:23, Kees Cook wrote:
> Hello!
>
> This is an experimental automated report about issues detected by Coverity
> from a scan of next-20191025 as part of the linux-next weekly scan project:
> https://scan.coverity.com/projects/linux-next-weekly-scan
>
> You're getting this email because you were associated with the identified
> lines of code (noted below) that were touched by recent commits:
>
> f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
JFTR This seems misleading wrt to the issue reported here AFAICS. The
code was there even before this commit.
> Coverity reported the following:
>
> *** CID 1487368: Error handling issues (CHECKED_RETURN)
> /mm/memcontrol.c: 2343 in reclaim_high()
> 2337 gfp_t gfp_mask)
> 2338 {
> 2339 do {
> 2340 if (page_counter_read(&memcg->memory) <= memcg->high)
> 2341 continue;
> 2342 memcg_memory_event(memcg, MEMCG_HIGH);
> vvv CID 1487368: Error handling issues (CHECKED_RETURN)
> vvv Calling "try_to_free_mem_cgroup_pages" without checking return value (as is done elsewhere 5 out of 6 times).
> 2343 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
Yes we do not check for the return value here because the high limit is
a best effort feature. A more highlevel throttling which is not based on
the reclaim directly is implemented in mem_cgroup_handle_over_high
> 2344 } while ((memcg = parent_mem_cgroup(memcg)));
> 2345 }
> 2346
> 2347 static void high_work_func(struct work_struct *work)
> 2348 {
>
> If this is a false positive, please let us know so we can mark it as
> such, or teach the Coverity rules to be smarter. If not, please make
> sure fixes get into linux-next. :) For patches fixing this, please
> include:
>
> Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
> Addresses-Coverity-ID: 1487368 ("Error handling issues")
> Fixes: f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller")
>
>
> Thanks for your attention!
>
> --
> Coverity-bot
--
Michal Hocko
SUSE Labs
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