diff --git a/tools/linuxfs/preload/netif.c b/tools/linuxfs/preload/netif.c
index 078f6a301..41775e135 100644
--- a/tools/linuxfs/preload/netif.c
+++ b/tools/linuxfs/preload/netif.c
@@ -483,12 +483,12 @@ static FILE *synthesize(const char *table) {
 }
 
 /* tracer.c */
-int bl_status_without_tracer(const char *path, int flags) __attribute__((visibility("hidden")));
+int bl_status_without_tracer(const char *path, int flags, const void *caller) __attribute__((visibility("hidden")));
 
 static FILE *open_stream(const char *symbol, const char *path, const char *mode) {
     typedef FILE *(*fopen_fn)(const char *, const char *);
     int status = mode && mode[0] == 'r' && !strchr(mode, '+')
-            ? bl_status_without_tracer(path, O_RDONLY | O_CLOEXEC) : -1;
+            ? bl_status_without_tracer(path, O_RDONLY | O_CLOEXEC, NULL) : -1;
     if (status >= 0) {
         FILE *copy = fdopen(status, "r");
         if (copy == NULL) close(status);
diff --git a/tools/linuxfs/preload/opens.c b/tools/linuxfs/preload/opens.c
index 4c8b6e165..497d0d865 100644
--- a/tools/linuxfs/preload/opens.c
+++ b/tools/linuxfs/preload/opens.c
@@ -33,7 +33,7 @@
 #include <string.h>
 #include <sys/types.h>
 
-int bl_status_without_tracer(const char *path, int flags) __attribute__((visibility("hidden")));
+int bl_status_without_tracer(const char *path, int flags, const void *caller) __attribute__((visibility("hidden")));
 int bl_writable_retry(int dirfd, const char *path, int flags) __attribute__((visibility("hidden")));
 
 static int retry_without_noatime(int fd, int flags) {
@@ -60,7 +60,7 @@ int open(const char *path, int flags, ...) {
     errno = EACCES;
     return -1;
   }
-  if ((fd = bl_status_without_tracer(path, flags)) >= 0) return fd;
+  if ((fd = bl_status_without_tracer(path, flags, __builtin_return_address(0))) >= 0) return fd;
   if (real_open == NULL) real_open = dlsym(RTLD_NEXT, "open");
   if (real_open == NULL) {
     errno = ENOSYS;
@@ -86,7 +86,7 @@ int openat(int dirfd, const char *path, int flags, ...) {
     errno = EACCES;
     return -1;
   }
-  if ((fd = bl_status_without_tracer(path, flags)) >= 0) return fd;
+  if ((fd = bl_status_without_tracer(path, flags, __builtin_return_address(0))) >= 0) return fd;
   if (real_openat == NULL) real_openat = dlsym(RTLD_NEXT, "openat");
   if (real_openat == NULL) {
     errno = ENOSYS;
diff --git a/tools/linuxfs/preload/tracer.c b/tools/linuxfs/preload/tracer.c
index 3fe6a8ca1..b7eaf52e3 100644
--- a/tools/linuxfs/preload/tracer.c
+++ b/tools/linuxfs/preload/tracer.c
@@ -18,6 +18,7 @@
  */
 #define _GNU_SOURCE
 #include <ctype.h>
+#include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -48,14 +49,20 @@ static int is_status_path(const char *path) {
 }
 
 /* Chromium stands its hang watchdogs down when it sees a tracer, and the client's web helper does
- * not come up within their patience here: it is left reading the truth. Not so for the x86-64
- * client under FEX (BL_WEBHELPER_HIDE_TRACER=1, set by bannerlator-steam-x64): its tier0 breaks
- * into the supposed debugger with int3 on the first failed assertion, and the web helper dies of
- * SIGTRAP a second after it starts. */
-static int is_web_helper(void) {
+ * not come up within their patience here: it is left reading the truth. Chromium also traps when a
+ * status descriptor it opened turns out not to be procfs. The x86-64 client under FEX
+ * (BL_WEBHELPER_HIDE_TRACER=1, set by bannerlator-steam-x64) still needs its tier0 told: tier0
+ * reads the status, sees the tracer, and breaks into the supposed debugger with int3 on the first
+ * failed assertion - the web helper died of SIGTRAP a second after it started. There tier0's own
+ * opens (by caller) get the copy and Chromium's the real file. */
+static int is_web_helper(const void *caller) {
   if (strcmp(program_invocation_short_name, "steamwebhelper") != 0) return 0;
   const char *hide = getenv("BL_WEBHELPER_HIDE_TRACER");
-  return !(hide && hide[0] == '1');
+  Dl_info info;
+  if (hide && hide[0] == '1' && caller && dladdr(caller, &info) && info.dli_fname
+      && strstr(info.dli_fname, "libtier0_s.so"))
+    return 0;
+  return 1;
 }
 
 static int write_all(int fd, const char *data, size_t len) {
@@ -71,13 +78,13 @@ static int write_all(int fd, const char *data, size_t len) {
 
 /* The descriptor to hand back for a read-only open of a status file, or -1 with errno untouched
  * when the path is something else or the copy cannot be made, and the real open should run. */
-__attribute__((visibility("hidden"))) int bl_status_without_tracer(const char *path, int flags) {
+__attribute__((visibility("hidden"))) int bl_status_without_tracer(const char *path, int flags, const void *caller) {
   char text[STATUS_MAX];
   size_t len = 0;
   int saved = errno;
   int out = -1;
 
-  if ((flags & O_ACCMODE) != O_RDONLY || !is_status_path(path) || is_web_helper()) return -1;
+  if ((flags & O_ACCMODE) != O_RDONLY || !is_status_path(path) || is_web_helper(caller)) return -1;
   int in = (int)syscall(SYS_openat, AT_FDCWD, path, O_RDONLY | O_CLOEXEC);
   if (in < 0) goto done;
   for (;;) {