[DTrace-devel] [PATCH 05/20] memcpy: error-check

Nick Alcock nick.alcock at oracle.com
Wed May 11 21:12:47 UTC 2022


This FIXME is pretty easy to implement.

Signed-off-by: Nick Alcock <nick.alcock at oracle.com>
Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
---
 libdtrace/dt_cg.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
index d35d71394a5f..ac5e41553188 100644
--- a/libdtrace/dt_cg.c
+++ b/libdtrace/dt_cg.c
@@ -800,6 +800,8 @@ dt_cg_trace(dt_irlist_t *dlp _dt_unused_, dt_regset_t *drp _dt_unused_,
 static void
 dt_cg_memcpy(dt_irlist_t *dlp, dt_regset_t *drp, int dst, int src, size_t size)
 {
+	uint_t		lbl_ok = dt_irlist_label(dlp);
+
 	if (dt_regset_xalloc_args(drp) == -1)
 		longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
 
@@ -809,7 +811,12 @@ dt_cg_memcpy(dt_irlist_t *dlp, dt_regset_t *drp, int dst, int src, size_t size)
 	dt_regset_xalloc(drp, BPF_REG_0);
 	emit(dlp, BPF_CALL_HELPER(BPF_FUNC_probe_read));
 	dt_regset_free_args(drp);
-	/* FIXME: check BPF_REG_0 for error? */
+
+	emit(dlp,  BPF_BRANCH_IMM(BPF_JEQ, BPF_REG_0, 0, lbl_ok));
+	dt_cg_probe_error(yypcb, DTRACEFLT_BADADDR, 0, 0);
+	emitl(dlp, lbl_ok,
+	      BPF_NOP());
+
 	dt_regset_free(drp, BPF_REG_0);
 }
 
-- 
2.36.1.263.g194b774378.dirty




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