Fix kmalloc overflow in LPFC driver at large core count

Fix kmalloc overflow in LPFC driver at large core count

Submitted by james.smart  james.smart.@avagotech.com

From:       james.smart@avagotech.com (James Smart)

Note: original patch modified by me to resolve unused variable warning

From: ian mitchell <imitchell@sgi.com>

This patch allows the LPFC to start up without a fatal kernel bug based
on an exceeded KMALLOC_MAX_SIZE and a too large NR_CPU-based maskbits
field. The bug was based on the number of CPU cores in a system.
Using the get_cpu_mask() function declared in kernel/cpu.c allows the
driver to load on the community kernel 4.2 RC1.

Below is the kernel bug reproduced:

8<--------------------------------------------------------------------
2199382.828437 (    0.005216)| lpfc 0003:02:00.0: enabling device (0140 ->
0142)
2199382.999272 (    0.170835)| ------------[ cut here ]------------
2199382.999337 (    0.000065)| WARNING: CPU: 84 PID: 404 at
mm/slab_common.c:653 \
kmalloc_slab+0x2f/0x89() 2199383.004534 (    0.005197)| Modules linked in:
lpfc(+) \
usbcore(+) mptctl scsi_transport_fc sg lpc_ich i2c_i801 usb_common tpm_tis
mfd_core \
tpm acpi_cpufreq button scsi_dh_alua scsi_dh_rdacusbcore: registered new
device \
driver usb 2199383.020568 (    0.016034)|
2199383.020581 (    0.000013)|  scsi_dh_hp_sw scsi_dh_emc scsi_dh gru thermal
sata_nv \
processor piix fan thermal_sysehci_hcd: USB 2.0 'Enhanced' Host Controller
(EHCI) \
Driver 2199383.035288 (    0.014707)|
2199383.035306 (    0.000018)|  hwmon ata_piix
2199383.035336 (    0.000030)| CPU: 84 PID: 404 Comm: kworker/84:0 Not tainted
\
3.18.0-rc2-gat-00106-ga7ca10f-dirty #178 2199383.047077 (    0.011741)|
ehci-pci: \
EHCI PCI platform driver 2199383.047134 (    0.000057)| Hardware name: SGI \
UV2000/ROMLEY, BIOS SGI UV 2000/3000 series BIOS 01/15/2013 2199383.056245 (
\
0.009111)| Workqueue: events work_for_cpu_fn 2199383.066174 (    0.009929)|  \
000000000000028d ffff88eef827bbe8 ffffffff815a542f 000000000000028d
2199383.069545 (  \
0.003371)|  ffffffff810ea142 ffff88eef827bc28 ffffffff8104365c
ffff88eefe4006c8 \
2199383.076214 (    0.006669)|  0000000000000000 00000000000080d0
0000000000000000 \
0000000000000004 2199383.079213 (    0.002999)| Call Trace:
2199383.084084 (    0.004871)|  [<ffffffff815a542f>] dump_stack+0x49/0x62
2199383.087283 (    0.003199)|  [<ffffffff810ea142>] ? kmalloc_slab+0x2f/0x89
2199383.091415 (    0.004132)|  [<ffffffff8104365c>]
warn_slowpath_common+0x77/0x92
2199383.095197 (    0.003782)|  [<ffffffff8104368c>]
warn_slowpath_null+0x15/0x17
2199383.103336 (    0.008139)|  [<ffffffff810ea142>] kmalloc_slab+0x2f/0x89
2199383.107082 (    0.003746)|  [<ffffffff8110fd9e>] __kmalloc+0x13/0x16a
2199383.112531 (    0.005449)|  [<ffffffffa01a8ed9>] \
lpfc_pci_probe_one_s4+0x105b/0x1644 [lpfc] 2199383.115316 (    0.002785)|  \
[<ffffffff81302b92>] ? pci_bus_read_config_dword+0x75/0x87 2199383.123431 (
\
0.008115)|  [<ffffffffa01a951f>] lpfc_pci_probe_one+0x5d/0xcb5 [lpfc]
2199383.127364 \
(    0.003933)|  [<ffffffff81497119>] ? dbs_check_cpu+0x168/0x177
2199383.136438 (    \
0.009074)|  [<ffffffff81496fa5>] ? gov_queue_work+0xb4/0xc0 2199383.140407 (
\
0.003969)|  [<ffffffff8130b2a1>] local_pci_probe+0x1e/0x52 2199383.143105 (
\
0.002698)|  [<ffffffff81052c47>] work_for_cpu_fn+0x13/0x1b 2199383.147315 (
\
0.004210)|  [<ffffffff81054965>] process_one_work+0x222/0x35e 2199383.151379 (
\
0.004064)|  [<ffffffff81054e76>] worker_thread+0x3d5/0x46e 2199383.159402 (
\
0.008023)|  [<ffffffff81054aa1>] ? process_one_work+0x35e/0x35e 2199383.163097
(    \
0.003695)|  [<ffffffff810599c6>] kthread+0xc8/0xd2 2199383.167476 (
0.004379)|  \
[<ffffffff810598fe>] ? kthread_freezable_should_stop+0x5b/0x5b 2199383.176434
(    \
0.008958)|  [<ffffffff815a8cac>] ret_from_fork+0x7c/0xb0 2199383.180086 (    \
0.003652)|  [<ffffffff810598fe>] ? kthread_freezable_should_stop+0x5b/0x5b \
                2199383.192333 (    0.012247)| ehci-pci 0000:00:1a.0: EHCI
Host \
                Controller
-------------------------------------------------------------------->8
The proposed solution was approved by James Smart at Emulex and tested
on a UV2 machine with 6144 cores. With the fix, the LPFC module loads
with no unwanted effects on the system.

Signed-off-by: Ian Mitchell <imitchell@sgi.com>
Signed-off-by: Alex Thorlton <athorlton@sgi.com>
Suggested-by: Robert Elliot <elliott@hp.com>
Orabug: 22029622
From dick.kennedy@avagotech.com lpfc-10.5.0.1-11.0.0.3-1.tar.gz
Acked-by: Chuck Anderson <chuck.anderson@oracle.com>