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[5.10,63/96] net: igmp: increase size of mr_ifc_count

Message ID 20210816125437.048044635@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Aug. 16, 2021, 1:02 p.m. UTC
From: Eric Dumazet <edumazet@google.com>

[ Upstream commit b69dd5b3780a7298bd893816a09da751bc0636f7 ]

Some arches support cmpxchg() on 4-byte and 8-byte only.
Increase mr_ifc_count width to 32bit to fix this problem.

Fixes: 4a2b285e7e10 ("net: igmp: fix data-race in igmp_ifc_timer_expire()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210811195715.3684218-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/inetdevice.h | 2 +-
 net/ipv4/igmp.c            | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 3515ca64e638..b68fca08be27 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -41,7 +41,7 @@  struct in_device {
 	unsigned long		mr_qri;		/* Query Response Interval */
 	unsigned char		mr_qrv;		/* Query Robustness Variable */
 	unsigned char		mr_gq_running;
-	unsigned char		mr_ifc_count;
+	u32			mr_ifc_count;
 	struct timer_list	mr_gq_timer;	/* general query timer */
 	struct timer_list	mr_ifc_timer;	/* interface change timer */
 
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index a51360087b19..00576bae183d 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -803,7 +803,7 @@  static void igmp_gq_timer_expire(struct timer_list *t)
 static void igmp_ifc_timer_expire(struct timer_list *t)
 {
 	struct in_device *in_dev = from_timer(in_dev, t, mr_ifc_timer);
-	u8 mr_ifc_count;
+	u32 mr_ifc_count;
 
 	igmpv3_send_cr(in_dev);
 restart: