Messages in this thread Patch in this message | | | From | David Howells <> | Subject | [PATCH] disentangle printk's whilst oopsing on SMP | Date | Tue, 17 Jun 2003 15:36:43 +0100 |
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Hi Linus,
The attached patch stops printk's issued on different processors from becoming char-by-char interleaved whilst one of them is oopsing.
David
diff -uNr linux-2.5.72/kernel/printk.c linux-2.5.72-auto/kernel/printk.c --- linux-2.5.72/kernel/printk.c 2003-06-17 15:01:58.000000000 +0100 +++ linux-2.5.72-auto/kernel/printk.c 2003-06-17 15:06:31.000000000 +0100 @@ -373,6 +373,9 @@ logged_chars++; } +/* cpu currently holding logbuf_lock */ +static volatile int printk_cpu = -1; + /* * This is printk. It can be called from any context. We want it to work. * @@ -395,8 +398,9 @@ static char printk_buf[1024]; static int log_level_unknown = 1; - if (oops_in_progress) { - /* If a crash is occurring, make sure we can't deadlock */ + if (oops_in_progress && printk_cpu==smp_processor_id()) { + /* If a crash is occurring during printk() on this CPU, + * make sure we can't deadlock */ spin_lock_init(&logbuf_lock); /* And make sure that we print immediately */ init_MUTEX(&console_sem); @@ -404,6 +408,7 @@ /* This stops the holder of console_sem just where we want him */ spin_lock_irqsave(&logbuf_lock, flags); + printk_cpu = smp_processor_id(); /* Emit the output into the temporary buffer */ va_start(args, fmt); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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