| Message ID | 20240325183627.7641-1-davthompson@nvidia.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f7442a634ac06b953fc1f7418f307b25acd4cfbc |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v3] mlxbf_gige: call request_irq() after NAPI initialized | expand |
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Mon, 25 Mar 2024 14:36:27 -0400 you wrote: > The mlxbf_gige driver encounters a NULL pointer exception in > mlxbf_gige_open() when kdump is enabled. The sequence to reproduce > the exception is as follows: > a) enable kdump > b) trigger kdump via "echo c > /proc/sysrq-trigger" > c) kdump kernel executes > d) kdump kernel loads mlxbf_gige module > e) the mlxbf_gige module runs its open() as the > the "oob_net0" interface is brought up > f) mlxbf_gige module will experience an exception > during its open(), something like: > > [...] Here is the summary with links: - [net,v3] mlxbf_gige: call request_irq() after NAPI initialized https://git.kernel.org/netdev/net/c/f7442a634ac0 You are awesome, thank you!
diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c index cef0e2d3f1a7..77134ca92938 100644 --- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c +++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c @@ -139,13 +139,10 @@ static int mlxbf_gige_open(struct net_device *netdev) control |= MLXBF_GIGE_CONTROL_PORT_EN; writeq(control, priv->base + MLXBF_GIGE_CONTROL); - err = mlxbf_gige_request_irqs(priv); - if (err) - return err; mlxbf_gige_cache_stats(priv); err = mlxbf_gige_clean_port(priv); if (err) - goto free_irqs; + return err; /* Clear driver's valid_polarity to match hardware, * since the above call to clean_port() resets the @@ -166,6 +163,10 @@ static int mlxbf_gige_open(struct net_device *netdev) napi_enable(&priv->napi); netif_start_queue(netdev); + err = mlxbf_gige_request_irqs(priv); + if (err) + goto napi_deinit; + /* Set bits in INT_EN that we care about */ int_en = MLXBF_GIGE_INT_EN_HW_ACCESS_ERROR | MLXBF_GIGE_INT_EN_TX_CHECKSUM_INPUTS | @@ -182,14 +183,17 @@ static int mlxbf_gige_open(struct net_device *netdev) return 0; +napi_deinit: + netif_stop_queue(netdev); + napi_disable(&priv->napi); + netif_napi_del(&priv->napi); + mlxbf_gige_rx_deinit(priv); + tx_deinit: mlxbf_gige_tx_deinit(priv); phy_deinit: phy_stop(phydev); - -free_irqs: - mlxbf_gige_free_irqs(priv); return err; }
The mlxbf_gige driver encounters a NULL pointer exception in mlxbf_gige_open() when kdump is enabled. The sequence to reproduce the exception is as follows: a) enable kdump b) trigger kdump via "echo c > /proc/sysrq-trigger" c) kdump kernel executes d) kdump kernel loads mlxbf_gige module e) the mlxbf_gige module runs its open() as the the "oob_net0" interface is brought up f) mlxbf_gige module will experience an exception during its open(), something like: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000086000004 EC = 0x21: IABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000086000004 [#1] SMP CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : 0x0 lr : __napi_poll+0x40/0x230 sp : ffff800008003e00 x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8 x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000 x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000 x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0 x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398 x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2 x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238 Call trace: 0x0 net_rx_action+0x178/0x360 __do_softirq+0x15c/0x428 __irq_exit_rcu+0xac/0xec irq_exit+0x18/0x2c handle_domain_irq+0x6c/0xa0 gic_handle_irq+0xec/0x1b0 call_on_irq_stack+0x20/0x2c do_interrupt_handler+0x5c/0x70 el1_interrupt+0x30/0x50 el1h_64_irq_handler+0x18/0x2c el1h_64_irq+0x7c/0x80 __setup_irq+0x4c0/0x950 request_threaded_irq+0xf4/0x1bc mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige] mlxbf_gige_open+0x5c/0x170 [mlxbf_gige] __dev_open+0x100/0x220 __dev_change_flags+0x16c/0x1f0 dev_change_flags+0x2c/0x70 do_setlink+0x220/0xa40 __rtnl_newlink+0x56c/0x8a0 rtnl_newlink+0x58/0x84 rtnetlink_rcv_msg+0x138/0x3c4 netlink_rcv_skb+0x64/0x130 rtnetlink_rcv+0x20/0x30 netlink_unicast+0x2ec/0x360 netlink_sendmsg+0x278/0x490 __sock_sendmsg+0x5c/0x6c ____sys_sendmsg+0x290/0x2d4 ___sys_sendmsg+0x84/0xd0 __sys_sendmsg+0x70/0xd0 __arm64_sys_sendmsg+0x2c/0x40 invoke_syscall+0x78/0x100 el0_svc_common.constprop.0+0x54/0x184 do_el0_svc+0x30/0xac el0_svc+0x48/0x160 el0t_64_sync_handler+0xa4/0x12c el0t_64_sync+0x1a4/0x1a8 Code: bad PC value ---[ end trace 7d1c3f3bf9d81885 ]--- Kernel panic - not syncing: Oops: Fatal exception in interrupt Kernel Offset: 0x2870a7a00000 from 0xffff800008000000 PHYS_OFFSET: 0x80000000 CPU features: 0x0,000005c1,a3332a5a Memory Limit: none ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]--- The exception happens because there is a pending RX interrupt before the call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires immediately after this request_irq() completes. The RX IRQ handler runs "napi_schedule()" before NAPI is fully initialized via "netif_napi_add()" and "napi_enable()", both which happen later in the open() logic. The logic in mlxbf_gige_open() must fully initialize NAPI before any calls to request_irq() execute. Fixes: f92e1869d74e ("Add Mellanox BlueField Gigabit Ethernet driver") Signed-off-by: David Thompson <davthompson@nvidia.com> Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com> --- v3 - code change to add missing phy_stop() was moved to its own commit, which has already been merged - re-worded commit message accordingly v2 - re-worded commit message and subject for clarity - updated commit message to mention that phy_stop() was added to the error path in mlxbf_gige_open() --- .../mellanox/mlxbf_gige/mlxbf_gige_main.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)