Re: [PATCH net] bnxt_en: bring back rtnl lock in bnxt_shutdown
From: Breno Leitao <leitao@debian.org>
Date: 2025-03-31 11:45:41
Also in:
lkml
Hello Stanislav, On Fri, Mar 28, 2025 at 10:42:16AM -0700, Stanislav Fomichev wrote:
Taehee reports missing rtnl from bnxt_shutdown path: inetdev_event (./include/linux/inetdevice.h:256 net/ipv4/devinet.c:1585) notifier_call_chain (kernel/notifier.c:85) __dev_close_many (net/core/dev.c:1732 (discriminator 3)) kernel/locking/mutex.c:713 kernel/locking/mutex.c:732) dev_close_many (net/core/dev.c:1786) netif_close (./include/linux/list.h:124 ./include/linux/list.h:215 bnxt_shutdown (drivers/net/ethernet/broadcom/bnxt/bnxt.c:16707) bnxt_en pci_device_shutdown (drivers/pci/pci-driver.c:511) device_shutdown (drivers/base/core.c:4820) kernel_restart (kernel/reboot.c:271 kernel/reboot.c:285)
I've got this issue as well.
Bring back the rtnl lock. Link: https://lore.kernel.org/netdev/CAMArcTV4P8PFsc6O2tSgzRno050DzafgqkLA2b7t=Fv_SY=brw@mail.gmail.com/ (local) Fixes: 004b5008016a ("eth: bnxt: remove most dependencies on RTNL") Reported-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Tested-by: Breno Leitao <leitao@debian.org>
quoted hunk ↗ jump to hunk
--- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 934ba9425857..1a70605fad38 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c@@ -16698,6 +16698,7 @@ static void bnxt_shutdown(struct pci_dev *pdev) if (!dev) return; + rtnl_lock(); netdev_lock(dev);
can't we leverage the `struct net_device->lock` for the shutdown.
Basically we have the lock the single device we are turning it down.
I am wondering if we really need the big RTNL lock. This is my
understanding of what is happening:
pci_device_shutdown() is called for a single device
- netdev_lock(dev)
- netif_close(dev);
- dev_close_many(&single, true);
- __dev_close_many()
- ASSERT_RTNL();
Basically we ware only closing one device, and the net_device->lock
is already held. Shouldn't it be enough?
Can we do something like this (from my naive point of view):
static void __dev_close_many(struct list_head *head)
{
struct net_device *dev;
- ASSERT_RTNL();
might_sleep();
list_for_each_entry(dev, head, close_list) {
+ ASSERT_RTNL_NET(dev);
...
}
Thanks
--breno