From 9fcf986cc4bc6a3a39f23fbcbbc3a9e52d3c24fd Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 16 Feb 2022 09:32:16 -0800 Subject: ipv4: fix data races in fib_alias_hw_flags_set fib_alias_hw_flags_set() can be used by concurrent threads, and is only RCU protected. We need to annotate accesses to following fields of struct fib_alias: offload, trap, offload_failed Because of READ_ONCE()WRITE_ONCE() limitations, make these field u8. BUG: KCSAN: data-race in fib_alias_hw_flags_set / fib_alias_hw_flags_set read to 0xffff888134224a6a of 1 bytes by task 2013 on cpu 1: fib_alias_hw_flags_set+0x28a/0x470 net/ipv4/fib_trie.c:1050 nsim_fib4_rt_hw_flags_set drivers/net/netdevsim/fib.c:350 [inline] nsim_fib4_rt_add drivers/net/netdevsim/fib.c:367 [inline] nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:429 [inline] nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline] nsim_fib_event_work+0x1852/0x2cf0 drivers/net/netdevsim/fib.c:1477 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 process_scheduled_works kernel/workqueue.c:2370 [inline] worker_thread+0x7df/0xa70 kernel/workqueue.c:2456 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 write to 0xffff888134224a6a of 1 bytes by task 4872 on cpu 0: fib_alias_hw_flags_set+0x2d5/0x470 net/ipv4/fib_trie.c:1054 nsim_fib4_rt_hw_flags_set drivers/net/netdevsim/fib.c:350 [inline] nsim_fib4_rt_add drivers/net/netdevsim/fib.c:367 [inline] nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:429 [inline] nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline] nsim_fib_event_work+0x1852/0x2cf0 drivers/net/netdevsim/fib.c:1477 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 process_scheduled_works kernel/workqueue.c:2370 [inline] worker_thread+0x7df/0xa70 kernel/workqueue.c:2456 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 value changed: 0x00 -> 0x02 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 4872 Comm: kworker/0:0 Not tainted 5.17.0-rc3-syzkaller-00188-g1d41d2e82623-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_fib_event_work Fixes: 90b93f1b31f8 ("ipv4: Add "offload" and "trap" indications to routes") Signed-off-by: Eric Dumazet Reported-by: syzbot Reviewed-by: Ido Schimmel Link: https://lore.kernel.org/r/20220216173217.3792411-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski --- net/ipv4/route.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/route.c') diff --git a/net/ipv4/route.c b/net/ipv4/route.c index ff6f91cdb6c4..f33ad1f383b6 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -3395,8 +3395,8 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, fa->fa_tos == fri.tos && fa->fa_info == res.fi && fa->fa_type == fri.type) { - fri.offload = fa->offload; - fri.trap = fa->trap; + fri.offload = READ_ONCE(fa->offload); + fri.trap = READ_ONCE(fa->trap); break; } } -- cgit v1.2.3-59-g8ed1b