mlxbf_gige: call request_irq() after NAPI initialized

In the Linux kernel, the following vulnerability has been resolved:

mlxbf_gige: call request_irq() after NAPI initialized

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

---truncated---