[PATCH] print_cfq_rq: per_cpu(xx, 0) may not exist

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* [PATCH] print_cfq_rq: per_cpu(xx, 0) may not exist
@ 2010-11-18 10:23 Sonny Rao
  2010-11-18 10:23 ` [PATCH] Fix crash in sym53c8xx_2 error path Sonny Rao
  0 siblings, 1 reply; 2+ messages in thread
From: Sonny Rao @ 2010-11-18 10:23 UTC (permalink / raw)
  To: linux-kernel; +Cc: Sonny Rao, Milton Miller, Ingo Molnar, Peter Zijlstra

Per cpu variables only exist for possible cpus.  On some architectures
and platforms, cpu 0 may not be possible, and this debug code generates
an oops.

As a variable for the boot cpu seems to be architecture dependent, replace
this aparently arbitrary choice of reference for spread of min vruntime
across run queues from that of cpu 0 to that of the first online cpu.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Sonny Rao <sonnyrao@linux.vnet.ibm.com>
---
 kernel/sched_debug.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 2e1b0d1..be586db 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -163,7 +163,7 @@ static void task_group_path(struct task_group *tg, char *buf, int buflen)
 void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 {
 	s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
-		spread, rq0_min_vruntime, spread0;
+		spread, spread0;
 	struct rq *rq = cpu_rq(cpu);
 	struct sched_entity *last;
 	unsigned long flags;
@@ -188,7 +188,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	if (last)
 		max_vruntime = last->vruntime;
 	min_vruntime = cfs_rq->min_vruntime;
-	rq0_min_vruntime = cpu_rq(0)->cfs.min_vruntime;
 	raw_spin_unlock_irqrestore(&rq->lock, flags);
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "MIN_vruntime",
 			SPLIT_NS(MIN_vruntime));
@@ -199,7 +198,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	spread = max_vruntime - MIN_vruntime;
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread",
 			SPLIT_NS(spread));
-	spread0 = min_vruntime - rq0_min_vruntime;
+	spread0 = min_vruntime - per_cpu(runqueues,
+			cpumask_first(cpu_online_mask)).cfs.min_vruntime;
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread0",
 			SPLIT_NS(spread0));
 	SEQ_printf(m, "  .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
-- 
1.5.6.5


^ permalink raw reply	[flat|nested] 2+ messages in thread

* [PATCH] Fix crash in sym53c8xx_2 error path
  2010-11-18 10:23 [PATCH] print_cfq_rq: per_cpu(xx, 0) may not exist Sonny Rao
@ 2010-11-18 10:23 ` Sonny Rao
  0 siblings, 0 replies; 2+ messages in thread
From: Sonny Rao @ 2010-11-18 10:23 UTC (permalink / raw)
  To: linux-kernel
  Cc: Sonny Rao, Milton Miller, Matthew Wilcox, James E.J. Bottomley,
	linux-scsi

We have observed NULL pointer dereference crashes in sym53c8xx_2
when a command cannot be found, fix it to check for this case
and print out [unknown cmd] if this happens.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Sonny Rao <sonnyrao@linux.vnet.ibm.com>
---
 drivers/scsi/sym53c8xx_2/sym_hipd.c |   50 +++++++++++++++++++++++++++-------
 1 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_hipd.c b/drivers/scsi/sym53c8xx_2/sym_hipd.c
index 2c3e89d..ad9543e 100644
--- a/drivers/scsi/sym53c8xx_2/sym_hipd.c
+++ b/drivers/scsi/sym53c8xx_2/sym_hipd.c
@@ -70,9 +70,15 @@ static void sym_printl_hex(u_char *p, int n)
 	printf (".\n");
 }

-static void sym_print_msg(struct sym_ccb *cp, char *label, u_char *msg)
+static void sym_print_msg(struct sym_hcb *np, struct sym_ccb *cp, char *label,
+	u_char *msg)
 {
-	sym_print_addr(cp->cmd, "%s: ", label);
+	if (cp->cmd) {
+		sym_print_addr(cp->cmd, "%s: ", label);
+	} else {
+		shost_printk(KERN_INFO, np->s.host, "[unknown cmd]"
+		"%s: ", label);
+	}

 	spi_print_msg(msg);
 	printf("\n");
@@ -4412,7 +4418,11 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  been selected with ATN.  We do not want to handle that.
 	 */
 	case SIR_SEL_ATN_NO_MSG_OUT:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		if (cp)
+			scmd_printk(KERN_WARNING, cp->cmd,
+				"No MSG OUT phase after selection with ATN\n");
+		else
+			shost_printk(KERN_WARNING, np->s.host, "[unknown cmd]"
 				"No MSG OUT phase after selection with ATN\n");
 		goto out_stuck;
 	/*
@@ -4420,7 +4430,11 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  having reselected the initiator.
 	 */
 	case SIR_RESEL_NO_MSG_IN:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		if (cp)
+			scmd_printk(KERN_WARNING, cp->cmd,
+				"No MSG IN phase after reselection\n");
+		else
+			shost_printk(KERN_WARNING, np->s.host, "[unknown cmd]"
 				"No MSG IN phase after reselection\n");
 		goto out_stuck;
 	/*
@@ -4428,7 +4442,11 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  an IDENTIFY.
 	 */
 	case SIR_RESEL_NO_IDENTIFY:
-		scmd_printk(KERN_WARNING, cp->cmd,
+		if (cp)
+			scmd_printk(KERN_WARNING, cp->cmd,
+				"No IDENTIFY after reselection\n");
+		else
+			shost_printk(KERN_WARNING, np->s.host, "[unknown cmd]"
 				"No IDENTIFY after reselection\n");
 		goto out_stuck;
 	/*
@@ -4457,7 +4475,11 @@ static void sym_int_sir(struct sym_hcb *np)
 	case SIR_RESEL_ABORTED:
 		np->lastmsg = np->msgout[0];
 		np->msgout[0] = M_NOOP;
-		scmd_printk(KERN_WARNING, cp->cmd,
+		if (cp)
+			scmd_printk(KERN_WARNING, cp->cmd,
+			"message %x sent on bad reselection\n", np->lastmsg);
+		else
+			shost_printk(KERN_WARNING, np->s.host, "[unknown cmd]"
 			"message %x sent on bad reselection\n", np->lastmsg);
 		goto out;
 	/*
@@ -4491,7 +4513,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  REJECT message.
 	 */
 	case SIR_REJECT_TO_SEND:
-		sym_print_msg(cp, "M_REJECT to send for ", np->msgin);
+		sym_print_msg(np, cp, "M_REJECT to send for ", np->msgin);
 		np->msgout[0] = M_REJECT;
 		goto out;
 	/*
@@ -4555,7 +4577,7 @@ static void sym_int_sir(struct sym_hcb *np)
 			switch (np->msgin [2]) {
 			case M_X_MODIFY_DP:
 				if (DEBUG_FLAGS & DEBUG_POINTER)
-					sym_print_msg(cp, "extended msg ",
+					sym_print_msg(np, cp, "extended msg ",
 						      np->msgin);
 				tmp = (np->msgin[3]<<24) + (np->msgin[4]<<16) + 
 				      (np->msgin[5]<<8)  + (np->msgin[6]);
@@ -4583,7 +4605,7 @@ static void sym_int_sir(struct sym_hcb *np)
 		 */
 		case M_IGN_RESIDUE:
 			if (DEBUG_FLAGS & DEBUG_POINTER)
-				sym_print_msg(cp, "1 or 2 byte ", np->msgin);
+				sym_print_msg(np, cp, "1 or 2 byte ", np->msgin);
 			if (cp->host_flags & HF_SENSE)
 				OUTL_DSP(np, SCRIPTA_BA(np, clrack));
 			else
@@ -4593,7 +4615,13 @@ static void sym_int_sir(struct sym_hcb *np)
 			if (INB(np, HS_PRT) == HS_NEGOTIATE)
 				sym_nego_rejected(np, tp, cp);
 			else {
-				sym_print_addr(cp->cmd,
+				if (cp)
+					sym_print_addr(cp->cmd,
+					"M_REJECT received (%x:%x).\n",
+					scr_to_cpu(np->lastmsg), np->msgout[0]);
+				else
+					shost_printk(KERN_INFO, np->s.host,
+					"[unknown cmd]"
 					"M_REJECT received (%x:%x).\n",
 					scr_to_cpu(np->lastmsg), np->msgout[0]);
 			}
@@ -4608,7 +4636,7 @@ static void sym_int_sir(struct sym_hcb *np)
 	 *  Ignore all MSG IN phases and reject it.
 	 */
 	case SIR_MSG_WEIRD:
-		sym_print_msg(cp, "WEIRD message received", np->msgin);
+		sym_print_msg(np, cp, "WEIRD message received", np->msgin);
 		OUTL_DSP(np, SCRIPTB_BA(np, msg_weird));
 		return;
 	/*
-- 
1.5.6.5


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2010-11-18 19:21 UTC | newest]

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2010-11-18 10:23 [PATCH] print_cfq_rq: per_cpu(xx, 0) may not exist Sonny Rao
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