diff --git a/math/openblas/files/patch-interface__trsm.c b/math/openblas/files/patch-interface__trsm.c
new file mode 100644
index 000000000000..e0488bf5adb7
--- /dev/null
+++ b/math/openblas/files/patch-interface__trsm.c
@@ -0,0 +1,30 @@
+Revert upstream commit fd862d43b ("Remove redundant quick return").
+
+That commit removed an unconditional `if ((args.m == 0) || (args.n == 0))
+return;` from interface/trsm.c on the assumption that it had been made
+redundant by an earlier-added quick-return (commit 74486799b). The
+assumption holds for the ARM64-SME direct-kernel path but NOT for the
+x86_64 DYNAMIC_ARCH path: SMP block-fanout in level3_thread.c can
+produce per-block bm=0 even when the caller passed a non-zero args.m,
+and the late return was the only thing protecting the
+strsm_kernel_RT_BARCELONA prologue from being entered with degenerate
+dimensions. The BARCELONA prologue then walks %r8 off 16-byte alignment
+(r8 += bn*bk*4 with bn=7, bk=7 = 196 bytes, mod 16 = 4) and the tail
+loop SIGBUSes on `movaps (%r8),%xmm3`.
+
+Reproducer: math/openblas 0.3.33 with DYNAMIC_ARCH on AMD64 fails the
+`sblat3` test driver in the STRSM block, killed by SIGBUS.
+
+Upstream report: https://github.com/OpenMathLib/OpenBLAS/issues/<TBD>
+
+--- interface/trsm.c.orig	2026-04-23 13:50:46 UTC
++++ interface/trsm.c
+@@ -383,6 +383,8 @@ if (strcmp(gotoblas_corename(), "armv9sme") == 0
+
+ #endif
+
++  if ((args.m == 0) || (args.n == 0)) return;
++
+   IDEBUG_START;
+
+   FUNCTION_PROFILE_START();