The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cbe9e51126305832cf407ee6bb556ce831488ffe Mon Sep 17 00:00:00 2001 From: Ivan Vecera ivecera@redhat.com Date: Mon, 8 Aug 2022 19:58:45 +0200 Subject: [PATCH] iavf: Fix deadlock in initialization
Fix deadlock that occurs when iavf interface is a part of failover configuration.
1. Mutex crit_lock is taken at the beginning of iavf_watchdog_task() 2. Function iavf_init_config_adapter() is called when adapter state is __IAVF_INIT_CONFIG_ADAPTER 3. iavf_init_config_adapter() calls register_netdevice() that emits NETDEV_REGISTER event 4. Notifier function failover_event() then calls net_failover_slave_register() that calls dev_open() 5. dev_open() calls iavf_open() that tries to take crit_lock in end-less loop
Stack trace: ... [ 790.251876] usleep_range_state+0x5b/0x80 [ 790.252547] iavf_open+0x37/0x1d0 [iavf] [ 790.253139] __dev_open+0xcd/0x160 [ 790.253699] dev_open+0x47/0x90 [ 790.254323] net_failover_slave_register+0x122/0x220 [net_failover] [ 790.255213] failover_slave_register.part.7+0xd2/0x180 [failover] [ 790.256050] failover_event+0x122/0x1ab [failover] [ 790.256821] notifier_call_chain+0x47/0x70 [ 790.257510] register_netdevice+0x20f/0x550 [ 790.258263] iavf_watchdog_task+0x7c8/0xea0 [iavf] [ 790.259009] process_one_work+0x1a7/0x360 [ 790.259705] worker_thread+0x30/0x390
To fix the situation we should check the current adapter state after first unsuccessful mutex_trylock() and return with -EBUSY if it is __IAVF_INIT_CONFIG_ADAPTER.
Fixes: 226d528512cf ("iavf: fix locking of critical sections") Signed-off-by: Ivan Vecera ivecera@redhat.com Tested-by: Konrad Jankowski konrad0.jankowski@intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com
diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index 95d4348e7579..f39440ad5c50 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -4088,8 +4088,17 @@ static int iavf_open(struct net_device *netdev) return -EIO; }
- while (!mutex_trylock(&adapter->crit_lock)) + while (!mutex_trylock(&adapter->crit_lock)) { + /* If we are in __IAVF_INIT_CONFIG_ADAPTER state the crit_lock + * is already taken and iavf_open is called from an upper + * device's notifier reacting on NETDEV_REGISTER event. + * We have to leave here to avoid dead lock. + */ + if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER) + return -EBUSY; + usleep_range(500, 1000); + }
if (adapter->state != __IAVF_DOWN) { err = -EBUSY;