Olivier Cochard
0d7f3796e9
Upstream issue: https://github.com/OpenMathLib/OpenBLAS/issues/5810 PR: 292566 Approved by: thierry
31 lines
1.2 KiB
C
31 lines
1.2 KiB
C
Revert upstream commit fd862d43b ("Remove redundant quick return").
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That commit removed an unconditional `if ((args.m == 0) || (args.n == 0))
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return;` from interface/trsm.c on the assumption that it had been made
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redundant by an earlier-added quick-return (commit 74486799b). The
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assumption holds for the ARM64-SME direct-kernel path but NOT for the
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x86_64 DYNAMIC_ARCH path: SMP block-fanout in level3_thread.c can
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produce per-block bm=0 even when the caller passed a non-zero args.m,
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and the late return was the only thing protecting the
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strsm_kernel_RT_BARCELONA prologue from being entered with degenerate
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dimensions. The BARCELONA prologue then walks %r8 off 16-byte alignment
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(r8 += bn*bk*4 with bn=7, bk=7 = 196 bytes, mod 16 = 4) and the tail
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loop SIGBUSes on `movaps (%r8),%xmm3`.
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Reproducer: math/openblas 0.3.33 with DYNAMIC_ARCH on AMD64 fails the
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`sblat3` test driver in the STRSM block, killed by SIGBUS.
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Upstream report: https://github.com/OpenMathLib/OpenBLAS/issues/<TBD>
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--- interface/trsm.c.orig 2026-04-23 13:50:46 UTC
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+++ interface/trsm.c
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@@ -383,6 +383,8 @@ if (strcmp(gotoblas_corename(), "armv9sme") == 0
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#endif
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+ if ((args.m == 0) || (args.n == 0)) return;
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+
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IDEBUG_START;
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FUNCTION_PROFILE_START();
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