On Mon, 9 Jun 2003 15:58:04 -0400 ,
"Sanders, Richard" <Richard.Sanders@xxxxxxxxxxx> wrote:
>Here is a patch for kdb/kdb_io.c which fixes a SMP race on the printf lock.
>Patch is against 4.2.
>--- linux/kdb/kdb_io.c.orig Mon Jun 9 15:45:54 2003
>+++ linux/kdb/kdb_io.c Mon Jun 9 15:47:08 2003
>@@ -493,10 +493,11 @@
> * 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)) {
>+ spin_lock(&kdb_printf_lock);
>+ if (!KDB_STATE(PRINTF_LOCK))
> KDB_STATE_SET(PRINTF_LOCK);
>- spin_lock(&kdb_printf_lock);
>- }
>+ else
>+ spin_unlock(&kdb_printf_lock);
>
> diag = kdbgetintenv("LINES", &linecount);
> if (diag || linecount <= 1)
>@@ -592,8 +593,8 @@
> console_loglevel = saved_loglevel;
> }
> if (KDB_STATE(PRINTF_LOCK)) {
>- spin_unlock(&kdb_printf_lock);
> KDB_STATE_CLEAR(PRINTF_LOCK);
>+ spin_unlock(&kdb_printf_lock);
> }
> if (do_longjmp)
> #ifdef KDB_HAVE_LONGJMP
Rejected. Read the comments at the start of your patch, you just
introduced a recursion deadlock.
BTW, your patch was in quoted printable. Like Linus, I tend to ignore
encoded patches unless they are so large that they have to be zipped.
Please send small patchs in plain text, not as encoded attachments.
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