On Wed, 7 May 2003 18:05:30 -0700,
"Randy.Dunlap" <rddunlap@osdl.org> wrote:
>I have several oopses that are garbled. Part of the problem is that
>page fault code (x86: arch/i386/mm/fault.c) does not attempt to
>serialize the "Unable to handle kernel ... at virtual address ..."
>messages, since it's considered better to get _some_ messages out
>than no messages. (and serialize it with what?)
>
>However, after untwisting these, I can tell you that unraveling
>them is not fun.
>
>Can these be cleaned up in any reasonable way?
>Any suggestions?
kdb_printf() has this:
/* Serialize kdb_printf if multiple cpus try to write at once.
* But if any cpu goes recursive in kdb, just print the output,
* even if it is interleaved with any other text.
*/
if (!KDB_STATE(PRINTF_LOCK)) {
KDB_STATE_SET(PRINTF_LOCK);
spin_lock(&kdb_printf_lock);
}
....
if (KDB_STATE(PRINTF_LOCK)) {
spin_unlock(&kdb_printf_lock);
KDB_STATE_CLEAR(PRINTF_LOCK);
}
KDB_STATE() is a per-cpu set of flags, PRINTF_LOCK indicates if this
cpu has got or is trying to get the kdb_printf_lock. I get no
interleave problems, except when somebody prints a line in multiple
calls to kdb_printf(), the fragments are printed as one chunk but the
individual fragments can be interleaved.
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This archive was generated by hypermail 2b29 : Fri May 23 2003 - 22:00:33 EST