RE: [Bug 7505] Linux-2.6.18 fails to boot on AMD64 machine

["Zhang, Yanmin" <yanmin.zhang@intel.com>]

>>-----Original Message-----
>>From: Ard -kwaak- van Breemen [mailto:ard@telegraafnet.nl]
>>Sent: 2006年12月22日 5:06
>>To: Zhang, Yanmin
>>Cc: Andrew Morton; Chuck Ebbert; Yinghai Lu; take@libero.it; agalanin@mera.ru; linux-kernel@vger.kernel.org;
>>bugme-daemon@bugzilla.kernel.org; Eric W. Biederman
>>Subject: Re: [Bug 7505] Linux-2.6.18 fails to boot on AMD64 machine
>>
>>On Thu, Dec 21, 2006 at 04:04:04PM +0800, Zhang, Yanmin wrote:
>>> I couldn't reproduce it on my EM64T machine. I instrumented function start_kernel and
>>> didn't find irq was enabled before calling init_IRQ. It'll be better if the reporter could
>>> instrument function start_kernel to capture which function enables irq.
>>
>>Editing init/main.c:
>>        preempt_disable();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT17");
>>        build_all_zonelists();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT18");
>>        page_alloc_init();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT19");
>>        printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
>>        parse_early_param();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT20");
>>        parse_args("Booting kernel", command_line, __start___param,
>>                   __stop___param - __start___param,
>>                   &unknown_bootoption);
>>                printk("BLAAT21");
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>        sort_main_extable();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT22");
>>        trap_init();
>>        if (!irqs_disabled())
>>                printk("start_kernel(): bug: interrupts were enabled early\n");
>>                printk("BLAAT23");
>>
>>Results in:
>>^MAllocating PCI resources starting at 88000000 (gap: 80000000:60000000)
>>^MBLAAT12BLAAT13<6>PERCPU: Allocating 32960 bytes of per cpu data
>>^MBLAAT14BLAAT15BLAAT16BLAAT17Built 2 zonelists.  Total pages: 1032635
>>^MBLAAT18BLAAT19<5>Kernel command line: console=tty0 console=ttyS0,115200 hdb=noprobe hdc=noprobe hdd=noprobe root=/dev/md0 ro panic=30
>>earlyprintk=serial,ttyS0,115200
>>^MBLAAT20<6>ide_setup: hdb=noprobe
>>^Mide_setup: hdc=noprobe
>>^Mide_setup: hdd=noprobe
>>^MBLAAT21start_kernel(): bug: interrupts were enabled early
>>^Mstart_kernel(): bug: interrupts were enabled early
>>^MBLAAT22Initializing CPU#0
>>
>>Hmmm, that actually doesn't make sense to me (unless parse_args is able to enable irq's).
I think parse_args enables irq when it calls callbacks.
Could you try below?
1) Test Andrew's patch of sema down_write;
2) Apply below patch and see what the output is when booting. If the output has
"[BUG]..address.", Pls. map the address to function name by System.map.

--- linux-2.6.19/kernel/params.c	2006-12-08 15:32:49.000000000 +0800
+++ linux-2.6.19_work/kernel/params.c	2006-12-22 12:28:38.000000000 +0800
@@ -53,13 +53,22 @@ static int parse_one(char *param,
 		     int (*handle_unknown)(char *param, char *val))
 {
 	unsigned int i;
+	int result;
+	int irq_is_disabled;
 
 	/* Find parameter */
 	for (i = 0; i < num_params; i++) {
 		if (parameq(param, params[i].name)) {
 			DEBUGP("They are equal!  Calling %p\n",
 			       params[i].set);
-			return params[i].set(val, &params[i]);
+			irq_is_disabled = irqs_disabled();
+			result = params[i].set(val, &params[i]);
+			if (irq_is_disabled && !irqs_disabled())
+			{
+				printk("[BUG] parse_one: function %p enabled irq!\n",
+						params[i].set);
+			}
+			return result;
 		}
 	}
 
--- linux-2.6.19/init/main.c	2006-12-08 15:32:49.000000000 +0800
+++ linux-2.6.19_work/init/main.c	2006-12-22 12:28:50.000000000 +0800
@@ -181,6 +181,7 @@ static int __init obsolete_checksetup(ch
 {
 	struct obs_kernel_param *p;
 	int had_early_param = 0;
+	int result, irq_is_disabled;
 
 	p = __setup_start;
 	do {
@@ -197,8 +198,17 @@ static int __init obsolete_checksetup(ch
 				printk(KERN_WARNING "Parameter %s is obsolete,"
 				       " ignored\n", p->str);
 				return 1;
-			} else if (p->setup_func(line + n))
-				return 1;
+			} else {
+				irq_is_disabled = irqs_disabled();
+				result = p->setup_func(line + n);
+				if (irq_is_disabled && !irqs_disabled())
+				{
+					printk("[BUG] obsolete_checksetup: function %p enabled irq!\n",
+							p->setup_func);
+				}
+				if (result)
+					return 1;
+			}
 		}
 		p++;
 	} while (p < __setup_end);
-
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/