[PATCH net 5/5] ipv6: mcast: use jiffies_delta_to_clock_t() in igmp6_mc_seq_show()
From: Eric Dumazet <edumazet@google.com>
Date: 2026-08-26 10:37:21
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
If a multicast group timer has expired but the delayed work has
not yet run to clear MAF_TIMER_RUNNING, expires - jiffies produces
a negative value.
Because unsigned arithmetic was used with jiffies_to_clock_t(),
expires - jiffies underflows to a huge value and reports invalid
timer durations in /proc/net/igmp6.
Use jiffies_delta_to_clock_t() with a signed long delta to properly
cap expired deltas to 0, matching IPv4 igmp_mc_seq_show() and commit
a399a8053164 ("time: jiffies_delta_to_clock_t() helper to the rescue").
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv6/mcast.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index a90dddba719726f36e0d5176c5e0574d1a488d5e..65916dc3a3146ccb7edba2984042b093ae1cd4f8 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c@@ -3030,7 +3030,7 @@ static int igmp6_mc_seq_show(struct seq_file *seq, void *v) struct ifmcaddr6 *im = (struct ifmcaddr6 *)v; struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq); unsigned int mca_flags = READ_ONCE(im->mca_flags); - unsigned long expires = READ_ONCE(im->mca_work.timer.expires); + long delta = READ_ONCE(im->mca_work.timer.expires) - jiffies; seq_printf(seq, "%-4d %-15s %pi6 %5d %08X %ld\n",
@@ -3038,7 +3038,7 @@ static int igmp6_mc_seq_show(struct seq_file *seq, void *v) &im->mca_addr, READ_ONCE(im->mca_users), mca_flags, (mca_flags & MAF_TIMER_RUNNING) ? - jiffies_to_clock_t(expires - jiffies) : 0); + jiffies_delta_to_clock_t(delta) : 0); return 0; }
--
2.55.0.860.g4b6b3295ed-goog