diff mbox series

[v3,2/3] net: sched: consistently use rcu_replace_pointer() in taprio_change()

Message ID 20240830101754.1574848-3-dmantipov@yandex.ru (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [v3,1/3] net: sched: fix use-after-free in taprio_change() | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 4 maintainers not CCed: xiyou.wangcong@gmail.com jiri@resnulli.us edumazet@google.com jhs@mojatatu.com
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-31--15-00 (tests: 714)

Commit Message

Dmitry Antipov Aug. 30, 2024, 10:16 a.m. UTC
According to Vinicius (and carefully looking through the whole thing
once again), txtime branch of 'taprio_change()' is not going to race
against 'advance_sched()'. But using 'rcu_replace_pointer()' in the
former may be a good idea as well.

Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
v3: unchanged since v2
v2: added to the series
---
 net/sched/sch_taprio.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 59fad74d5ff9..9f4e004cdb8b 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -1952,7 +1952,9 @@  static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 			goto unlock;
 		}
 
-		rcu_assign_pointer(q->admin_sched, new_admin);
+		/* Not going to race against advance_sched(), but still */
+		admin = rcu_replace_pointer(q->admin_sched, new_admin,
+					    lockdep_rtnl_is_held());
 		if (admin)
 			call_rcu(&admin->rcu, taprio_free_sched_cb);
 	} else {