Re: Linux 6.3-rc1

[Linus Torvalds]

On Mon, Mar 6, 2023 at 8:52 AM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> Various crashes, affecting several architectures.
>
> [   11.664666] BUG: unable to handle page fault for address: 000000000002d3db
> [   11.667043]  lock_acquire+0xcb/0x330
> [   11.667163]  _raw_spin_lock+0x2b/0x40
> [   11.667255]  add_timer_on+0x92/0x150
> [   11.667302]  try_to_generate_entropy+0x256/0x280

Ok, this seems to be due to the issue discussed here

   https://lore.kernel.org/all/CAHk-=witXXeQuP9fgs4dDL2Ex0meXQiHJs+3JEfNdaPwngMVEg@xxxxxxxxxxxxxx/

and I think the fix is as per the appended patch (that particular
crash is due to the random.c part, but I did the others that 'git
grep' picked out too).

Can you run your test-runs on this patch?

              Linus
 arch/powerpc/xmon/xmon.c         |  2 +-
 drivers/char/random.c            |  2 +-
 drivers/net/wireguard/queueing.h |  2 +-
 drivers/scsi/lpfc/lpfc_init.c    | 14 +++++++-------
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 73c620c2a3a1..e753a6bd4888 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1275,7 +1275,7 @@ static int xmon_batch_next_cpu(void)
 	while (!cpumask_empty(&xmon_batch_cpus)) {
 		cpu = cpumask_next_wrap(smp_processor_id(), &xmon_batch_cpus,
 					xmon_batch_start_cpu, true);
-		if (cpu == nr_cpumask_bits)
+		if (cpu >= nr_cpu_ids)
 			break;
 		if (xmon_batch_start_cpu == -1)
 			xmon_batch_start_cpu = cpu;
diff --git a/drivers/char/random.c b/drivers/char/random.c
index ce3ccd172cc8..253f2ddb8913 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1311,7 +1311,7 @@ static void __cold try_to_generate_entropy(void)
 			/* Basic CPU round-robin, which avoids the current CPU. */
 			do {
 				cpu = cpumask_next(cpu, &timer_cpus);
-				if (cpu == nr_cpumask_bits)
+				if (cpu >= nr_cpu_ids)
 					cpu = cpumask_first(&timer_cpus);
 			} while (cpu == smp_processor_id() && num_cpus > 1);
 
diff --git a/drivers/net/wireguard/queueing.h b/drivers/net/wireguard/queueing.h
index 583adb37ee1e..125284b346a7 100644
--- a/drivers/net/wireguard/queueing.h
+++ b/drivers/net/wireguard/queueing.h
@@ -106,7 +106,7 @@ static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id)
 {
 	unsigned int cpu = *stored_cpu, cpu_index, i;
 
-	if (unlikely(cpu == nr_cpumask_bits ||
+	if (unlikely(cpu >= nr_cpu_ids ||
 		     !cpumask_test_cpu(cpu, cpu_online_mask))) {
 		cpu_index = id % cpumask_weight(cpu_online_mask);
 		cpu = cpumask_first(cpu_online_mask);
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 61958a24a43d..73b544bfbb2e 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -12563,7 +12563,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 					goto found_same;
 				new_cpu = cpumask_next(
 					new_cpu, cpu_present_mask);
-				if (new_cpu == nr_cpumask_bits)
+				if (new_cpu >= nr_cpu_ids)
 					new_cpu = first_cpu;
 			}
 			/* At this point, we leave the CPU as unassigned */
@@ -12577,7 +12577,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 			 * selecting the same IRQ.
 			 */
 			start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (start_cpu == nr_cpumask_bits)
+			if (start_cpu >= nr_cpu_ids)
 				start_cpu = first_cpu;
 
 			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
@@ -12613,7 +12613,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 					goto found_any;
 				new_cpu = cpumask_next(
 					new_cpu, cpu_present_mask);
-				if (new_cpu == nr_cpumask_bits)
+				if (new_cpu >= nr_cpu_ids)
 					new_cpu = first_cpu;
 			}
 			/* We should never leave an entry unassigned */
@@ -12631,7 +12631,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 			 * selecting the same IRQ.
 			 */
 			start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (start_cpu == nr_cpumask_bits)
+			if (start_cpu >= nr_cpu_ids)
 				start_cpu = first_cpu;
 
 			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
@@ -12704,7 +12704,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				goto found_hdwq;
 			}
 			new_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (new_cpu == nr_cpumask_bits)
+			if (new_cpu >= nr_cpu_ids)
 				new_cpu = first_cpu;
 		}
 
@@ -12719,7 +12719,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				goto found_hdwq;
 
 			new_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (new_cpu == nr_cpumask_bits)
+			if (new_cpu >= nr_cpu_ids)
 				new_cpu = first_cpu;
 		}
 
@@ -12730,7 +12730,7 @@ lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
  found_hdwq:
 		/* We found an available entry, copy the IRQ info */
 		start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-		if (start_cpu == nr_cpumask_bits)
+		if (start_cpu >= nr_cpu_ids)
 			start_cpu = first_cpu;
 		cpup->hdwq = new_cpup->hdwq;
  logit: