Bug 137214 - netconsole freezes during printk() when output link not up
netconsole freezes during printk() when output link not up
Product: Red Hat Enterprise Linux 2.1
Classification: Red Hat
Component: kernel (Show other bugs)
i686 Linux
medium Severity medium
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Assigned To: Jeffrey Moyer
Brian Brock
Depends On: IT#36426
Blocks: 143573
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Reported: 2004-10-26 14:46 EDT by Alexandre Oliva
Modified: 2010-10-21 22:40 EDT (History)
4 users (show)

See Also:
Fixed In Version: RHSA-2006-0191
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2006-02-01 12:53:43 EST
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
Fix for e100 netconsole lockup (357 bytes, patch)
2005-01-22 22:30 EST, Steven Rostedt
no flags Details | Diff
fix hang in netconsole when doing a printk with link down (950 bytes, patch)
2005-09-08 11:16 EDT, Jeffrey Moyer
no flags Details | Diff

  None (edit)
Description Alexandre Oliva 2004-10-26 14:46:05 EDT
This is the RHEL2.1 version of bug #127815.  It is supposed to be
fixed by a patch that went into the RHEL3 U4 patch pool.

If you set up netconsole on a box with an e100 network card, unplug
the network cable for 20 seconds or so, then plug it back in, the
machine hangs right after printing the `e100: eth3 NIC Link is Up 100
Mbps Full duplex' message.
Comment 1 Jeffrey Moyer 2004-11-01 16:59:45 EST
Same patch submitted for inclusion in AS2.1.
Comment 2 Steven Rostedt 2005-01-22 22:30:21 EST
Created attachment 110099 [details]
Fix for e100 netconsole lockup

When the e100 overflows the transmit buffer, the queue is stopped and
e100_net_poll never starts it again. So netpoll_send_skb loops forever.
Comment 8 Jeffrey Moyer 2005-09-08 11:14:33 EDT
The patch posted in comment #2 is NOT the right fix for this issue.  The issue
we're discussing involves being unable to send a printk due to the network link
being down.  In this case, we loop forever in transmit_raw_skb.  The idea, here,
is that by calling the network adapter's poll routine, we will free up some
resources that will allow us to send the packet.  However, the inability to send
a packet is not caused by a lack of resources, in this case.

I'll attach the same fix that was applied in the RHEL 3 tree.
Comment 9 Jeffrey Moyer 2005-09-08 11:16:32 EDT
Created attachment 118599 [details]
fix hang in netconsole when doing a printk with link down

The previous patch is for a different problem.	This patch solves the problem
listed in this bugzilla.
Comment 16 Red Hat Bugzilla 2006-02-01 12:53:43 EST
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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