Bug 430484 - none/tests/arm64/atomics_v81 occassionally fails
Summary: none/tests/arm64/atomics_v81 occassionally fails
Status: REPORTED
Alias: None
Product: valgrind
Classification: Developer tools
Component: general (show other bugs)
Version: unspecified
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Julian Seward
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-12-16 22:27 UTC by Mark Wielaard
Modified: 2020-12-17 18:59 UTC (History)
2 users (show)

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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.