43 lines
1.4 KiB
Diff
43 lines
1.4 KiB
Diff
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From 0d563f713780eb274ebf995660917482452c127e Mon Sep 17 00:00:00 2001
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From: Yonghong Song <yhs@fb.com>
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Date: Fri, 26 Aug 2022 16:34:24 -0700
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Subject: [PATCH 1/2] Fix a llvm signed division error for compactsnoop tool
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Fix issue #4182.
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llvm doesn't support signed division and an assertion error
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will happen when the IR contains sdiv. The reason is
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due to code
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zone - zone_pgdat->node_zones
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where zone and zone_pgdat->node_zones are pointers to
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struct zone (with size 1664). So effectively the above
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is equivalent to
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((void *)zone - (void *)zone_pgdat->node_zones)/sizeof(struct zone)
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which is converted to sdiv insn.
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llvm11 seems okay and I didn't investigate why. But llvm14 and
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latest llvm16 failed with compiler fatal error.
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To fix the issue let us replace the above '(void *)' as
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'(u64)' and then the udiv will be used for the division.
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Signed-off-by: Yonghong Song <yhs@fb.com>
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---
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tools/compactsnoop.py | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/tools/compactsnoop.py b/tools/compactsnoop.py
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index 9daaf485..bf3c9b4b 100755
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--- a/tools/compactsnoop.py
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+++ b/tools/compactsnoop.py
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@@ -124,7 +124,7 @@ static inline int zone_idx_(struct zone *zone)
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{
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struct pglist_data *zone_pgdat = NULL;
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bpf_probe_read_kernel(&zone_pgdat, sizeof(zone_pgdat), &zone->zone_pgdat);
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- return zone - zone_pgdat->node_zones;
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+ return ((u64)zone - (u64)zone_pgdat->node_zones)/sizeof(struct zone);
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}
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#ifdef EXTNEDED_FIELDS
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--
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2.39.2
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