Bug 430484

Summary:	none/tests/arm64/atomics_v81 occassionally fails
Product:	[Developer tools] valgrind	Reporter:	Mark Wielaard <mark>
Component:	general	Assignee:	Julian Seward <jseward>
Status:	REPORTED ---
Severity:	normal	CC:	assad.hashmi, peter.maydell
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Mark Wielaard 2020-12-16 22:27:59 UTC

Sometimes, but of course not when I explicitly try, none/tests/arm64/atomics_v81 fails with:

cat none/tests/arm64/atomics_v81.stdout.diff 
--- atomics_v81.stdout.exp	2020-12-11 07:29:26.440663198 -0500
+++ atomics_v81.stdout.out	2020-12-16 17:09:36.965817433 -0500
@@ -15318,7 +15318,7 @@
 caspal x8, x9, x10, x11, [x5] :: rs 0000000000000000 0000000000000000 rt 0123456789abcdef 0123456789abcdef rn mem ffffffffffffffff ffffffffffffffff
 
 caspal x8, x9, x10, x11, [x5] :: rs ffffffffffffffff ffffffffffffffff rt 0123456789abcdef 0123456789abcdef rn mem ffffffffffffffff ffffffffffffffff
-caspal x8, x9, x10, x11, [x5] :: rs ffffffffffffffff ffffffffffffffff rt 0123456789abcdef 0123456789abcdef rn mem 0123456789abcdef 0123456789abcdef
+caspal x8, x9, x10, x11, [x5] :: rs ffffffffffffffff ffffffffffffffff rt 0123456789abcdef 0123456789abcdef rn mem ffffffffffffffff ffffffffffffffffFAIL: swapped but mem after != rt
 
 caspal x8, x9, x10, x11, [x5] :: rs ffffffffffffffff ffffffffffffffff rt fedcba9876543210 fedcba9876543210 rn mem 0000000000000000 0000000000000000
 caspal x8, x9, x10, x11, [x5] :: rs ffffffffffffffff ffffffffffffffff rt fedcba9876543210 fedcba9876543210 rn mem 0000000000000000 0000000000000000
EXPECTED RESULT

cpuinfo says:

processor	: 0
BogoMIPS	: 400.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics cpuid asimdrdm
CPU implementer	: 0x43
CPU architecture: 8
CPU variant	: 0x1
CPU part	: 0x0af
CPU revision	: 1

processor	: 1
BogoMIPS	: 400.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics cpuid asimdrdm
CPU implementer	: 0x43
CPU architecture: 8
CPU variant	: 0x1
CPU part	: 0x0af
CPU revision	: 1

processor	: 2
BogoMIPS	: 400.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics cpuid asimdrdm
CPU implementer	: 0x43
CPU architecture: 8
CPU variant	: 0x1
CPU part	: 0x0af
CPU revision	: 1

processor	: 3
BogoMIPS	: 400.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics cpuid asimdrdm
CPU implementer	: 0x43
CPU architecture: 8
CPU variant	: 0x1
CPU part	: 0x0af
CPU revision	: 1

It failed 2 times when trying ~30 times (the 2 times were the first run and the 8th run).

Comment 1 ahashmi 2020-12-17 18:59:02 UTC

CPU implementer 0x43 and CPU part 0x0af indicates a Cavium ThunderX2.

Previous experience with DynamoRIO suggests this behaviour may be limited to ThunderX machines only. It would be interesting to see if the same occasional failures occur on non-ThunderX machines.