bnx2: cancel timer on device removal

This oops was recently reported to me:

invalid opcode: 0000 [#1] SMP
last sysfs file:
/sys/devices/pci0000:00/0000:00:01.0/0000:01:0d.0/0000:02:05.0/device
CPU 1
Modules linked in: bnx2(+) sunrpc ipv6 dm_mirror dm_region_hash dm_log sg
microcode serio_raw amd64_edac_mod edac_core edac_mce_amd k8temp i2c_piix4
shpchp ext4 mbcache jbd2 sd_mod crc_t10dif mptsas mptscsih mptbase
scsi_transport_sas radeon ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core
dm_mod [last unloaded: bnx2]

Modules linked in: bnx2(+) sunrpc ipv6 dm_mirror dm_region_hash dm_log sg
microcode serio_raw amd64_edac_mod edac_core edac_mce_amd k8temp i2c_piix4
shpchp ext4 mbcache jbd2 sd_mod crc_t10dif mptsas mptscsih mptbase
scsi_transport_sas radeon ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core
dm_mod [last unloaded: bnx2]
Pid: 23900, comm: pidof Not tainted 2.6.32-130.el6.x86_64 #1 BladeCenter LS21
-[797251Z]-
RIP: 0010:[<ffffffffa058b270>]  [<ffffffffa058b270>] 0xffffffffa058b270
RSP: 0018:ffff880002083e48  EFLAGS: 00010246
RAX: ffff880002083e90 RBX: ffff88007ccd4000 RCX: 0000000000000000
RDX: 0000000000000100 RSI: dead000000200200 RDI: ffff8800007b8700
RBP: ffff880002083ed0 R08: ffff88000208db40 R09: 0000022d191d27c8
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800007b9bc8
R13: ffff880002083e90 R14: ffff8800007b8700 R15: ffffffffa058b270
FS:  00007fbb3bcf7700(0000) GS:ffff880002080000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001664a98 CR3: 0000000060395000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process pidof (pid: 23900, threadinfo ffff8800007e8000, task ffff8800091c0040)
Stack:
 ffffffff81079f77 ffffffff8109e010 ffff88007ccd5c20 ffff88007ccd5820
<0> ffff88007ccd5420 ffff8800007e9fd8 ffff8800007e9fd8 0000010000000000
<0> ffff88007ccd5020 ffff880002083e90 ffff880002083e90 ffffffff8102a00d
Call Trace:
 <IRQ>
 [<ffffffff81079f77>] ? run_timer_softirq+0x197/0x340
 [<ffffffff8109e010>] ? tick_sched_timer+0x0/0xc0
 [<ffffffff8102a00d>] ? lapic_next_event+0x1d/0x30
 [<ffffffff8106f737>] __do_softirq+0xb7/0x1e0
 [<ffffffff81092cc0>] ? hrtimer_interrupt+0x140/0x250
 [<ffffffff81185f90>] ? filldir+0x0/0xe0
 [<ffffffff8100c2cc>] call_softirq+0x1c/0x30
 [<ffffffff8100df05>] do_softirq+0x65/0xa0
 [<ffffffff8106f525>] irq_exit+0x85/0x90
 [<ffffffff814e3340>] smp_apic_timer_interrupt+0x70/0x9b
 [<ffffffff8100bc93>] apic_timer_interrupt+0x13/0x20
 <EOI>
 [<ffffffff81211ba5>] ? selinux_file_permission+0x45/0x150
 [<ffffffff81262a75>] ? _atomic_dec_and_lock+0x55/0x80
 [<ffffffff812050c6>] security_file_permission+0x16/0x20
 [<ffffffff811861c1>] vfs_readdir+0x71/0xe0
 [<ffffffff81186399>] sys_getdents+0x89/0xf0
 [<ffffffff8100b172>] system_call_fastpath+0x16/0x1b

It occured during some stress testing, in which the reporter was repeatedly
removing and modprobing the bnx2 module while doing various other random
operations on the bnx2 registered net device.  Noting that this error occured on
a serdes based device, we noted that there were a few ethtool operations (most
notably self_test and set_phys_id) that have execution paths that lead into
bnx2_setup_serdes_phy.  This function is notable because it executes a mod_timer
call, which starts the bp->timer running.  Currently bnx2 is setup to assume
that this timer only nees to be stopped when bnx2_close or bnx2_suspend is
called.  Since the above ethtool operations are not gated on the net device
having been opened however, that assumption is incorrect, and can lead to the
timer still running after the module has been removed, leading to the oops above
(as well as other simmilar oopses).

Fix the problem by ensuring that the timer is stopped when pci_device_unregister
is called.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Hushan Jia <hjia@redhat.com>
CC: Michael Chan <mchan@broadcom.com>
CC: "David S. Miller" <davem@davemloft.net>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bnx2.c

@@ -8413,6 +8413,8 @@ bnx2_remove_one(struct pci_dev *pdev)
 
 	unregister_netdev(dev);
 
+	del_timer_sync(&bp->timer);
+
 	if (bp->mips_firmware)
 		release_firmware(bp->mips_firmware);
 	if (bp->rv2p_firmware)