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[kvm-unit-tests,v5,1/2] s390x: sclp: treat system as single processor when read_info is NULL

Message ID 20230601164537.31769-2-pmorel@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series Fixing infinite loop on SCLP READ SCP INFO error | expand

Commit Message

Pierre Morel June 1, 2023, 4:45 p.m. UTC 
When a test abort()s before SCLP read info is completed, the assertion
on read_info in sclp_read_info() will fail. Since abort() eventually
calls smp_teardown() which in turn calls sclp_get_cpu_num(), this will
cause an infinite abort() chain, causing the test to hang.

Fix this by considering the system single processor when read_info is
missing.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
---
 lib/s390x/sclp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
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Patch

diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index acdc8a9..adf357b 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -119,8 +119,15 @@  void sclp_read_info(void)
 
 int sclp_get_cpu_num(void)
 {
-	assert(read_info);
-	return read_info->entries_cpu;
+	if (read_info)
+		return read_info->entries_cpu;
+	/*
+	 * Don't abort here if read_info is NULL since abort() calls
+	 * smp_teardown() which eventually calls this function and thus
+	 * causes an infinite abort() chain, causing the test to hang.
+	 * Since we obviously have at least one CPU, just return one.
+	 */
+	return 1;
 }
 
 CPUEntry *sclp_get_cpu_entries(void)