From 68ba44639537de6f91fe32783766322d41848127 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 22 Feb 2023 12:07:21 -0500 Subject: sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop With this refcnt added in sctp_stream_priorities, we don't need to traverse all streams to check if the prio is used by other streams when freeing one stream's prio in sctp_sched_prio_free_sid(). This can avoid a nested loop (up to 65535 * 65535), which may cause a stuck as Ying reported: watchdog: BUG: soft lockup - CPU#23 stuck for 26s! [ksoftirqd/23:136] Call Trace: sctp_sched_prio_free_sid+0xab/0x100 [sctp] sctp_stream_free_ext+0x64/0xa0 [sctp] sctp_stream_free+0x31/0x50 [sctp] sctp_association_free+0xa5/0x200 [sctp] Note that it doesn't need to use refcount_t type for this counter, as its accessing is always protected under the sock lock. v1->v2: - add a check in sctp_sched_prio_set to avoid the possible prio_head refcnt overflow. Fixes: 9ed7bfc79542 ("sctp: fix memory leak in sctp_stream_outq_migrate()") Reported-by: Ying Xu Acked-by: Marcelo Ricardo Leitner Signed-off-by: Xin Long Link: https://lore.kernel.org/r/825eb0c905cb864991eba335f4a2b780e543f06b.1677085641.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski --- include/net/sctp/structs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/sctp') diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index afa3781e3ca2..e1f6e7fc2b11 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1412,6 +1412,7 @@ struct sctp_stream_priorities { /* The next stream in line */ struct sctp_stream_out_ext *next; __u16 prio; + __u16 users; }; struct sctp_stream_out_ext { -- cgit v1.2.3