| Message ID | 20231201001911.656-1-thinhtr@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 16b55b1f2269962fb6b5154b8bf43f37c9a96637 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v4] net/tg3: fix race condition in tg3_reset_task() | expand |
On Thu, Nov 30, 2023 at 4:19 PM Thinh Tran <thinhtr@linux.vnet.ibm.com> wrote: > > When an EEH error is encountered by a PCI adapter, the EEH driver > modifies the PCI channel's state as shown below: > > enum { > /* I/O channel is in normal state */ > pci_channel_io_normal = (__force pci_channel_state_t) 1, > > /* I/O to channel is blocked */ > pci_channel_io_frozen = (__force pci_channel_state_t) 2, > > /* PCI card is dead */ > pci_channel_io_perm_failure = (__force pci_channel_state_t) 3, > }; > > If the same EEH error then causes the tg3 driver's transmit timeout > logic to execute, the tg3_tx_timeout() function schedules a reset > task via tg3_reset_task_schedule(), which may cause a race condition > between the tg3 and EEH driver as both attempt to recover the HW via > a reset action. > > EEH driver gets error event > --> eeh_set_channel_state() > and set device to one of > error state above scheduler: tg3_reset_task() get > returned error from tg3_init_hw() > --> dev_close() shuts down the interface > tg3_io_slot_reset() and > tg3_io_resume() fail to > reset/resume the device > > To resolve this issue, we avoid the race condition by checking the PCI > channel state in the tg3_reset_task() function and skip the tg3 driver > initiated reset when the PCI channel is not in the normal state. (The > driver has no access to tg3 device registers at this point and cannot > even complete the reset task successfully without external assistance.) > We'll leave the reset procedure to be managed by the EEH driver which > calls the tg3_io_error_detected(), tg3_io_slot_reset() and > tg3_io_resume() functions as appropriate. > > Adding the same checking in tg3_dump_state() to avoid dumping all > device registers when the PCI channel is not in the normal state. > > > Signed-off-by: Thinh Tran <thinhtr@linux.vnet.ibm.com> > Tested-by: Venkata Sai Duggi <venkata.sai.duggi@ibm.com> > Reviewed-by: David Christensen <drc@linux.vnet.ibm.com> > > v4: moving the PCI error checking to tg3_reset_task() and > tg3_dump_state() > v3: re-post the patch. > v2: checking PCI errors in tg3_tx_timeout() Thanks. Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Thu, 30 Nov 2023 18:19:11 -0600 you wrote: > When an EEH error is encountered by a PCI adapter, the EEH driver > modifies the PCI channel's state as shown below: > > enum { > /* I/O channel is in normal state */ > pci_channel_io_normal = (__force pci_channel_state_t) 1, > > [...] Here is the summary with links: - [v4] net/tg3: fix race condition in tg3_reset_task() https://git.kernel.org/netdev/net/c/16b55b1f2269 You are awesome, thank you!
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c index 48b6191efa56..49f299c868a1 100644 --- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c @@ -6474,6 +6474,14 @@ static void tg3_dump_state(struct tg3 *tp) int i; u32 *regs; + /* If it is a PCI error, all registers will be 0xffff, + * we don't dump them out, just report the error and return + */ + if (tp->pdev->error_state != pci_channel_io_normal) { + netdev_err(tp->dev, "PCI channel ERROR!\n"); + return; + } + regs = kzalloc(TG3_REG_BLK_SIZE, GFP_ATOMIC); if (!regs) return; @@ -11259,7 +11267,8 @@ static void tg3_reset_task(struct work_struct *work) rtnl_lock(); tg3_full_lock(tp, 0); - if (tp->pcierr_recovery || !netif_running(tp->dev)) { + if (tp->pcierr_recovery || !netif_running(tp->dev) || + tp->pdev->error_state != pci_channel_io_normal) { tg3_flag_clear(tp, RESET_TASK_PENDING); tg3_full_unlock(tp); rtnl_unlock();
When an EEH error is encountered by a PCI adapter, the EEH driver modifies the PCI channel's state as shown below: enum { /* I/O channel is in normal state */ pci_channel_io_normal = (__force pci_channel_state_t) 1, /* I/O to channel is blocked */ pci_channel_io_frozen = (__force pci_channel_state_t) 2, /* PCI card is dead */ pci_channel_io_perm_failure = (__force pci_channel_state_t) 3, }; If the same EEH error then causes the tg3 driver's transmit timeout logic to execute, the tg3_tx_timeout() function schedules a reset task via tg3_reset_task_schedule(), which may cause a race condition between the tg3 and EEH driver as both attempt to recover the HW via a reset action. EEH driver gets error event --> eeh_set_channel_state() and set device to one of error state above scheduler: tg3_reset_task() get returned error from tg3_init_hw() --> dev_close() shuts down the interface tg3_io_slot_reset() and tg3_io_resume() fail to reset/resume the device To resolve this issue, we avoid the race condition by checking the PCI channel state in the tg3_reset_task() function and skip the tg3 driver initiated reset when the PCI channel is not in the normal state. (The driver has no access to tg3 device registers at this point and cannot even complete the reset task successfully without external assistance.) We'll leave the reset procedure to be managed by the EEH driver which calls the tg3_io_error_detected(), tg3_io_slot_reset() and tg3_io_resume() functions as appropriate. Adding the same checking in tg3_dump_state() to avoid dumping all device registers when the PCI channel is not in the normal state. Signed-off-by: Thinh Tran <thinhtr@linux.vnet.ibm.com> Tested-by: Venkata Sai Duggi <venkata.sai.duggi@ibm.com> Reviewed-by: David Christensen <drc@linux.vnet.ibm.com> v4: moving the PCI error checking to tg3_reset_task() and tg3_dump_state() v3: re-post the patch. v2: checking PCI errors in tg3_tx_timeout() --- drivers/net/ethernet/broadcom/tg3.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)