diff options
| author | Breno Leitao <leitao@debian.org> | 2024-04-29 03:04:33 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-04-30 19:03:47 -0700 |
| commit | c2e6a872bde9912f1a7579639c5ca3adf1003916 (patch) | |
| tree | 8a9db18eb02e5ae6dbed4d046401fa832985130c | |
| parent | 3b5933e99c32fbf46d0c5f2232473ef87d919e16 (diff) | |
| download | net-next-c2e6a872bde9912f1a7579639c5ca3adf1003916.tar.gz | |
netpoll: Fix race condition in netpoll_owner_active
KCSAN detected a race condition in netpoll:
BUG: KCSAN: data-race in net_rx_action / netpoll_send_skb
write (marked) to 0xffff8881164168b0 of 4 bytes by interrupt on cpu 10:
net_rx_action (./include/linux/netpoll.h:90 net/core/dev.c:6712 net/core/dev.c:6822)
<snip>
read to 0xffff8881164168b0 of 4 bytes by task 1 on cpu 2:
netpoll_send_skb (net/core/netpoll.c:319 net/core/netpoll.c:345 net/core/netpoll.c:393)
netpoll_send_udp (net/core/netpoll.c:?)
<snip>
value changed: 0x0000000a -> 0xffffffff
This happens because netpoll_owner_active() needs to check if the
current CPU is the owner of the lock, touching napi->poll_owner
non atomically. The ->poll_owner field contains the current CPU holding
the lock.
Use an atomic read to check if the poll owner is the current CPU.
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240429100437.3487432-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/netpoll.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 543007f159f99..55bcacf67df3b 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -316,7 +316,7 @@ static int netpoll_owner_active(struct net_device *dev) struct napi_struct *napi; list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { - if (napi->poll_owner == smp_processor_id()) + if (READ_ONCE(napi->poll_owner) == smp_processor_id()) return 1; } return 0; |