• Prarit Bhargava's avatar
    bugs, x86: Fix printk levels for panic, softlockups and stack dumps · b0f4c4b3
    Prarit Bhargava authored
    rsyslog will display KERN_EMERG messages on a connected
    terminal.  However, these messages are useless/undecipherable
    for a general user.
    For example, after a softlockup we get:
     Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ...
     Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ...
     kernel:Call Trace:
     Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ...
     kernel:Code: ff ff a8 08 75 25 31 d2 48 8d 86 38 e0 ff ff 48 89
     d1 0f 01 c8 0f ae f0 48 8b 86 38 e0 ff ff a8 08 75 08 b1 01 4c 89 e0 0f 01 c9 <e8> ea 69 dd ff 4c 29 e8 48 89 c7 e8 0f bc da ff 49 89 c4 49 89
    This happens because the printk levels for these messages are
    incorrect. Only an informational message should be displayed on
    a terminal.
    I modified the printk levels for various messages in the kernel
    and tested the output by using the drivers/misc/lkdtm.c kernel
    modules (ie, softlockups, panics, hard lockups, etc.) and
    confirmed that the console output was still the same and that
    the output to the terminals was correct.
    For example, in the case of a softlockup we now see the much
    more informative:
     Message from syslogd@intel-s3e37-04 at Jan 25 10:18:06 ...
     BUG: soft lockup - CPU4 stuck for 60s!
    instead of the above confusing messages.
    AFAICT, the messages no longer have to be KERN_EMERG.  In the
    most important case of a panic we set console_verbose().  As for
    the other less severe cases the correct data is output to the
    console and /var/log/messages.
    Successfully tested by me using the drivers/misc/lkdtm.c module.
    Signed-off-by: default avatarPrarit Bhargava <prarit@redhat.com>
    Cc: dzickus@redhat.com
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Link: http://lkml.kernel.org/r/1327586134-11926-1-git-send-email-prarit@redhat.com
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
fault.c 28.8 KB