diff --git a/src/mux_h1.c b/src/mux_h1.c
index 3b09a9acf..c355edd0b 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -5364,6 +5364,10 @@ static int h1_dump_h1c_info(struct buffer *msg, struct h1c *h1c, const char *pfx
  * <h1s> is NULL. Returns non-zero if the stream is considered suspicious. May
  * emit multiple lines, each new one being prefixed with <pfx>, if <pfx> is not
  * NULL, otherwise a single line is used.
+ *
+ * Remember that this may be called in a signal context from a "show threads"
+ * or panic dump, so the code must be careful about each data it accesses.
+ * However data are stable since the dump happens from the owner thread.
  */
 static int h1_dump_h1s_info(struct buffer *msg, const struct h1s *h1s, const char *pfx)
 {
@@ -5378,7 +5382,7 @@ static int h1_dump_h1s_info(struct buffer *msg, const struct h1s *h1s, const cha
 	else
 		method = "UNKNOWN";
 
-	chunk_appendf(msg, " h1s=%p h1s.flg=0x%x .sd.flg=0x%x", h1s, h1s->flags, se_fl_get(h1s->sd));
+	chunk_appendf(msg, " h1s=%p h1s.flg=0x%x", h1s, h1s->flags);
 	chunk_appendf(msg, " .req.state=%s .res.state=%s", h1m_state_str(h1s->req.state), h1m_state_str(h1s->res.state));
 
 	if (pfx)
@@ -5387,10 +5391,12 @@ static int h1_dump_h1s_info(struct buffer *msg, const struct h1s *h1s, const cha
 	chunk_appendf(msg, " .meth=%s status=%d",
 		      method, h1s->status);
 
-	chunk_appendf(msg, " .sd.flg=0x%08x .sd.evts=%s", se_fl_get(h1s->sd), tevt_evts2str(h1s->sd->term_evts_log));
-	if (!se_fl_test(h1s->sd, SE_FL_ORPHAN)) {
-		chunk_appendf(msg, " .sc.flg=0x%08x .sc.app=%p .sc.evts=%s",
-			      h1s_sc(h1s)->flags, h1s_sc(h1s)->app, tevt_evts2str(h1s_sc(h1s)->term_evts_log));
+	if (h1s->sd) {
+		chunk_appendf(msg, " .sd.flg=0x%08x .sd.evts=%s", se_fl_get(h1s->sd), tevt_evts2str(h1s->sd->term_evts_log));
+		if (!se_fl_test(h1s->sd, SE_FL_ORPHAN)) {
+			chunk_appendf(msg, " .sc.flg=0x%08x .sc.app=%p .sc.evts=%s",
+				      h1s_sc(h1s)->flags, h1s_sc(h1s)->app, tevt_evts2str(h1s_sc(h1s)->term_evts_log));
+		}
 	}
 
 	if (pfx && h1s->subs)