kernel/linux.git/drivers/net/ethernet/micrel, branch v6.6.134

net: ks8851: Fix potential TX stall after interface reopen

2024-07-18T11:21:17+00:00

commit 7a99afef17af66c276c1d6e6f4dbcac223eaf6ac upstream. The amount of TX space in the hardware buffer is tracked in the tx_space variable. The initial value is currently only set during driver probing. After closing the interface and reopening it the tx_space variable has the last value it had before close. If it is smaller than the size of the first send packet after reopeing the interface the queue will be stopped. The queue is woken up after receiving a TX interrupt but this will never happen since we did not send anything. This commit moves the initialization of the tx_space variable to the ks8851_net_open function right before starting the TX queue. Also query the value from the hardware instead of using a hard coded value. Only the SPI chip variant is affected by this issue because only this driver variant actually depends on the tx_space variable in the xmit function. Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl Reviewed-by: Jacob Keller Link: https://patch.msgid.link/20240709195845.9089-1-rwahl@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net: ks8851: Fix deadlock with the SPI chip variant

2024-07-18T11:21:17+00:00

commit 0913ec336a6c0c4a2b296bd9f74f8e41c4c83c8c upstream. When SMP is enabled and spinlocks are actually functional then there is a deadlock with the 'statelock' spinlock between ks8851_start_xmit_spi and ks8851_irq: watchdog: BUG: soft lockup - CPU#0 stuck for 27s! call trace: queued_spin_lock_slowpath+0x100/0x284 do_raw_spin_lock+0x34/0x44 ks8851_start_xmit_spi+0x30/0xb8 ks8851_start_xmit+0x14/0x20 netdev_start_xmit+0x40/0x6c dev_hard_start_xmit+0x6c/0xbc sch_direct_xmit+0xa4/0x22c __qdisc_run+0x138/0x3fc qdisc_run+0x24/0x3c net_tx_action+0xf8/0x130 handle_softirqs+0x1ac/0x1f0 __do_softirq+0x14/0x20 ____do_softirq+0x10/0x1c call_on_irq_stack+0x3c/0x58 do_softirq_own_stack+0x1c/0x28 __irq_exit_rcu+0x54/0x9c irq_exit_rcu+0x10/0x1c el1_interrupt+0x38/0x50 el1h_64_irq_handler+0x18/0x24 el1h_64_irq+0x64/0x68 __netif_schedule+0x6c/0x80 netif_tx_wake_queue+0x38/0x48 ks8851_irq+0xb8/0x2c8 irq_thread_fn+0x2c/0x74 irq_thread+0x10c/0x1b0 kthread+0xc8/0xd8 ret_from_fork+0x10/0x20 This issue has not been identified earlier because tests were done on a device with SMP disabled and so spinlocks were actually NOPs. Now use spin_(un)lock_bh for TX queue related locking to avoid execution of softirq work synchronously that would lead to a deadlock. Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240706101337.854474-1-rwahl@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net: ks8851: Fix another TX stall caused by wrong ISR flag handling

2024-05-25T14:22:52+00:00

commit 317a215d493230da361028ea8a4675de334bfa1a upstream. Under some circumstances it may happen that the ks8851 Ethernet driver stops sending data. Currently the interrupt handler resets the interrupt status flags in the hardware after handling TX. With this approach we may lose interrupts in the time window between handling the TX interrupt and resetting the TX interrupt status bit. When all of the three following conditions are true then transmitting data stops: - TX queue is stopped to wait for room in the hardware TX buffer - no queued SKBs in the driver (txq) that wait for being written to hw - hardware TX buffer is empty and the last TX interrupt was lost This is because reenabling the TX queue happens when handling the TX interrupt status but if the TX status bit has already been cleared then this interrupt will never come. With this commit the interrupt status flags will be cleared before they are handled. That way we stop losing interrupts. The wrong handling of the ISR flags was there from the beginning but with commit 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") the issue becomes apparent. Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl Reviewed-by: Simon Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: ks8851: Queue RX packets in IRQ handler instead of disabling BHs

2024-05-17T10:02:21+00:00

[ Upstream commit e0863634bf9f7cf36291ebb5bfa2d16632f79c49 ] Currently the driver uses local_bh_disable()/local_bh_enable() in its IRQ handler to avoid triggering net_rx_action() softirq on exit from netif_rx(). The net_rx_action() could trigger this driver .start_xmit callback, which is protected by the same lock as the IRQ handler, so calling the .start_xmit from netif_rx() from the IRQ handler critical section protected by the lock could lead to an attempt to claim the already claimed lock, and a hang. The local_bh_disable()/local_bh_enable() approach works only in case the IRQ handler is protected by a spinlock, but does not work if the IRQ handler is protected by mutex, i.e. this works for KS8851 with Parallel bus interface, but not for KS8851 with SPI bus interface. Remove the BH manipulation and instead of calling netif_rx() inside the IRQ handler code protected by the lock, queue all the received SKBs in the IRQ handler into a queue first, and once the IRQ handler exits the critical section protected by the lock, dequeue all the queued SKBs and push them all into netif_rx(). At this point, it is safe to trigger the net_rx_action() softirq, since the netif_rx() call is outside of the lock that protects the IRQ handler. Fixes: be0384bf599c ("net: ks8851: Handle softirqs at the end of IRQ thread to fix hang") Tested-by: Ronald Wahl # KS8851 SPI Signed-off-by: Marek Vasut Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240502183436.117117-1-marex@denx.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: ks8851: Handle softirqs at the end of IRQ thread to fix hang

2024-04-17T09:19:29+00:00

[ Upstream commit be0384bf599cf1eb8d337517feeb732d71f75a6f ] The ks8851_irq() thread may call ks8851_rx_pkts() in case there are any packets in the MAC FIFO, which calls netif_rx(). This netif_rx() implementation is guarded by local_bh_disable() and local_bh_enable(). The local_bh_enable() may call do_softirq() to run softirqs in case any are pending. One of the softirqs is net_rx_action, which ultimately reaches the driver .start_xmit callback. If that happens, the system hangs. The entire call chain is below: ks8851_start_xmit_par from netdev_start_xmit netdev_start_xmit from dev_hard_start_xmit dev_hard_start_xmit from sch_direct_xmit sch_direct_xmit from __dev_queue_xmit __dev_queue_xmit from __neigh_update __neigh_update from neigh_update neigh_update from arp_process.constprop.0 arp_process.constprop.0 from __netif_receive_skb_one_core __netif_receive_skb_one_core from process_backlog process_backlog from __napi_poll.constprop.0 __napi_poll.constprop.0 from net_rx_action net_rx_action from __do_softirq __do_softirq from call_with_stack call_with_stack from do_softirq do_softirq from __local_bh_enable_ip __local_bh_enable_ip from netif_rx netif_rx from ks8851_irq ks8851_irq from irq_thread_fn irq_thread_fn from irq_thread irq_thread from kthread kthread from ret_from_fork The hang happens because ks8851_irq() first locks a spinlock in ks8851_par.c ks8851_lock_par() spin_lock_irqsave(&ksp->lock, ...) and with that spinlock locked, calls netif_rx(). Once the execution reaches ks8851_start_xmit_par(), it calls ks8851_lock_par() again which attempts to claim the already locked spinlock again, and the hang happens. Move the do_softirq() call outside of the spinlock protected section of ks8851_irq() by disabling BHs around the entire spinlock protected section of ks8851_irq() handler. Place local_bh_enable() outside of the spinlock protected section, so that it can trigger do_softirq() without the ks8851_par.c ks8851_lock_par() spinlock being held, and safely call ks8851_start_xmit_par() without attempting to lock the already locked spinlock. Since ks8851_irq() is protected by local_bh_disable()/local_bh_enable() now, replace netif_rx() with __netif_rx() which is not duplicating the local_bh_disable()/local_bh_enable() calls. Fixes: 797047f875b5 ("net: ks8851: Implement Parallel bus operations") Signed-off-by: Marek Vasut Link: https://lore.kernel.org/r/20240405203204.82062-2-marex@denx.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: ks8851: Inline ks8851_rx_skb()

2024-04-17T09:19:29+00:00

[ Upstream commit f96f700449b6d190e06272f1cf732ae8e45b73df ] Both ks8851_rx_skb_par() and ks8851_rx_skb_spi() call netif_rx(skb), inline the netif_rx(skb) call directly into ks8851_common.c and drop the .rx_skb callback and ks8851_rx_skb() wrapper. This removes one indirect call from the driver, no functional change otherwise. Signed-off-by: Marek Vasut Link: https://lore.kernel.org/r/20240405203204.82062-1-marex@denx.de Signed-off-by: Jakub Kicinski Stable-dep-of: be0384bf599c ("net: ks8851: Handle softirqs at the end of IRQ thread to fix hang") Signed-off-by: Sasha Levin

net: ks8851: Fix TX stall caused by TX buffer overrun

2024-01-01T12:42:42+00:00

commit 3dc5d44545453de1de9c53cc529cc960a85933da upstream. There is a bug in the ks8851 Ethernet driver that more data is written to the hardware TX buffer than actually available. This is caused by wrong accounting of the free TX buffer space. The driver maintains a tx_space variable that represents the TX buffer space that is deemed to be free. The ks8851_start_xmit_spi() function adds an SKB to a queue if tx_space is large enough and reduces tx_space by the amount of buffer space it will later need in the TX buffer and then schedules a work item. If there is not enough space then the TX queue is stopped. The worker function ks8851_tx_work() dequeues all the SKBs and writes the data into the hardware TX buffer. The last packet will trigger an interrupt after it was send. Here it is assumed that all data fits into the TX buffer. In the interrupt routine (which runs asynchronously because it is a threaded interrupt) tx_space is updated with the current value from the hardware. Also the TX queue is woken up again. Now it could happen that after data was sent to the hardware and before handling the TX interrupt new data is queued in ks8851_start_xmit_spi() when the TX buffer space had still some space left. When the interrupt is actually handled tx_space is updated from the hardware but now we already have new SKBs queued that have not been written to the hardware TX buffer yet. Since tx_space has been overwritten by the value from the hardware the space is not accounted for. Now we have more data queued then buffer space available in the hardware and ks8851_tx_work() will potentially overrun the hardware TX buffer. In many cases it will still work because often the buffer is written out fast enough so that no overrun occurs but for example if the peer throttles us via flow control then an overrun may happen. This can be fixed in different ways. The most simple way would be to set tx_space to 0 before writing data to the hardware TX buffer preventing the queuing of more SKBs until the TX interrupt has been handled. I have chosen a slightly more efficient (and still rather simple) way and track the amount of data that is already queued and not yet written to the hardware. When new SKBs are to be queued the already queued amount of data is honoured when checking free TX buffer space. I tested this with a setup of two linked KS8851 running iperf3 between the two in bidirectional mode. Before the fix I got a stall after some minutes. With the fix I saw now issues anymore after hours. Fixes: 3ba81f3ece3c ("net: Micrel KS8851 SPI network driver") Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Ben Dooks Cc: Tristram Ha Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20231214181112.76052-1-rwahl@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

ksz884x: Remove unused functions

2023-04-12T08:38:19+00:00

Remove unused functions. These functions may have some value in documenting the hardware. But that information may be accessed via SCM history. Flagged by clang-16 with W=1. No functional change intended. Compile tested only. Signed-off-by: Simon Horman Signed-off-by: David S. Miller

net: ksz884x: remove unused change variable

2023-03-31T06:18:48+00:00

clang with W=1 reports drivers/net/ethernet/micrel/ksz884x.c:3216:6: error: variable 'change' set but not used [-Werror,-Wunused-but-set-variable] int change = 0; ^ This variable is not used so remove it. Signed-off-by: Tom Rix Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230329125929.1808420-1-trix@redhat.com Signed-off-by: Jakub Kicinski

net: ksz884x: fix missing pci_disable_device() on error in pcidev_init()

2022-10-26T02:46:35+00:00

pci_disable_device() need be called while module exiting, switch to use pcim_enable(), pci_disable_device() will be called in pcim_release() while unbinding device. Fixes: 8ca86fd83eae ("net: Micrel KSZ8841/2 PCI Ethernet driver") Signed-off-by: Yang Yingliang Link: https://lore.kernel.org/r/20221024131338.2848959-1-yangyingliang@huawei.com Signed-off-by: Jakub Kicinski