Coverity: rds_send_remove_from_sock(): Null pointer dereferences

[coverity-bot <keescook@chromium.org>]

Hello!

This is an experimental semi-automated report about issues detected by
Coverity from a scan of next-20210408 as part of the linux-next 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 commits:

  Wed Apr 7 14:01:24 2021 -0700
    0c85a7e87465 ("net/rds: Avoid potential use after free in rds_send_remove_from_sock")

Coverity reported the following:

*** CID 1503716:  Null pointer dereferences  (REVERSE_INULL)
/net/rds/send.c: 668 in rds_send_remove_from_sock()
662     		}
663     		spin_unlock(&rs->rs_lock);
664
665     unlock_and_drop:
666     		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
667     		rds_message_put(rm);
vvv     CID 1503716:  Null pointer dereferences  (REVERSE_INULL)
vvv     Null-checking "rm" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
668     		if (was_on_sock && rm)
669     			rds_message_put(rm);
670     	}
671
672     	if (rs) {
673     		rds_wake_sk_sleep(rs);

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 these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1503716 ("Null pointer dereferences")
Fixes: 0c85a7e87465 ("net/rds: Avoid potential use after free in rds_send_remove_from_sock")

Thanks for your attention!

-- 
Coverity-bot