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Postings by wuzhouhui

How to update modules in iniramfs fastly

I know dracut can update modules in initramfs, but I think it is too
slow. So I'm wondering what is the fastest way to update modules in
initramfs of CentOS 7?

Thanks!

Network broke for a while when libvirtd start

When start service libvirtd by

service libvirtd start

the network will broke for a while and then reconnected.

Adjust type of rw in submit_bio from int to unsigned long

Hi, I am a developer who worked on CentOS. Recently I am working on porting one of my
block drivers from CentOS 6.x to CentOS 7.x.

soft lockup after set multicast_router of bridge and it's port to 2

After I set multicast_router of bridge and it's port to 2, like following:
echo 2 > /sys/devices/virtual/net/eth81/bridge/multicast_router
echo 2 > /sys/devices/virtual/net/bond2/brport/multicast_router
Then soft lockup occured:
Message from syslogd@node-0 at Jan 9 15:47:12 ...
kernel:BUG: soft lockup - CPU#0 stuck for 61s!

Can't see register value in crash vmcore

Kernel crashed by panic("string"), but I can't see any register in vmcore:

crash> bt
PID: 53331 TASK: ffff880c523ed540 CPU: 2 COMMAND: "bw_sd-ar-7-0_2"
#0 [ffff880c4f12f978] machine_kexec at ffffffff81038ed9
#1 [ffff880c4f12f9d8] crash_kexec at ffffffff810c5a82
#2 [ffff880c4f12faa8] panic at ffffffff815113b2
#3 [ffff880c4f12fb28] sd_submit_bio at ffffffffa0747a02 [sd]
#4 [ffff880c4f12fb68] submit_clone_bio at ffffffffa0747d2b [sd]
#5 [ffff880c4f12fb78] split_and_submit_bio_for_cbd at ffffffffa0747ec9 [sd]
#6 [ffff880c4f12fbf8] sd_make_request at ffffffffa074c812 [sd]
#7 [ffff880c4

Null deference panic in CentOS-6.5

Hi,

I got a panic when running CentOS-6.5:

crash> bt
PID: 106074 TASK: ffff8839c1e32ae0 CPU: 4 COMMAND: "flushd4[cbd-sd-"
#0 [ffff8839c2a91900] machine_kexec at ffffffff81038fa9
#1 [ffff8839c2a91960] crash_kexec at ffffffff810c5992
#2 [ffff8839c2a91a30] oops_end at ffffffff81515c90
#3 [ffff8839c2a91a60] no_context at ffffffff81049f1b
#4 [ffff8839c2a91ab0] __bad_area_nosemaphore at ffffffff8104a1a5
#5 [ffff8839c2a91b00] bad_area_nosemaphore at ffffffff8104a273
#6 [ffff8839c2a91b10] __do_page_fault at ffffffff8104a9bf
#7 [ffff8839c2a91c30] do_page_fault at ffffffff8