diff --git a/firefox-glibc-dynstack.patch b/firefox-glibc-dynstack.patch
new file mode 100644
index 0000000..b0487d7
--- /dev/null
+++ b/firefox-glibc-dynstack.patch
@@ -0,0 +1,64 @@
+diff -ur firefox-90.0.orig/js/xpconnect/src/XPCJSContext.cpp firefox-90.0/js/xpconnect/src/XPCJSContext.cpp
+--- firefox-90.0.orig/js/xpconnect/src/XPCJSContext.cpp	2021-07-05 21:16:02.000000000 +0200
++++ firefox-90.0/js/xpconnect/src/XPCJSContext.cpp	2021-07-19 15:01:24.083460460 +0200
+@@ -85,14 +85,6 @@
+ using namespace xpc;
+ using namespace JS;
+ 
+-// The watchdog thread loop is pretty trivial, and should not require much stack
+-// space to do its job. So only give it 32KiB or the platform minimum.
+-#if !defined(PTHREAD_STACK_MIN)
+-#  define PTHREAD_STACK_MIN 0
+-#endif
+-static constexpr size_t kWatchdogStackSize =
+-    PTHREAD_STACK_MIN < 32 * 1024 ? 32 * 1024 : PTHREAD_STACK_MIN;
+-
+ static void WatchdogMain(void* arg);
+ class Watchdog;
+ class WatchdogManager;
+@@ -163,7 +155,7 @@
+       // watchdog, we need to join it on shutdown.
+       mThread = PR_CreateThread(PR_USER_THREAD, WatchdogMain, this,
+                                 PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD,
+-                                PR_JOINABLE_THREAD, kWatchdogStackSize);
++                                PR_JOINABLE_THREAD, 0);
+       if (!mThread) {
+         MOZ_CRASH("PR_CreateThread failed!");
+       }
+Only in firefox-90.0/js/xpconnect/src: XPCJSContext.cpp.firefox-glibc-dynstack
+diff -ur firefox-90.0.orig/security/sandbox/linux/launch/SandboxLaunch.cpp firefox-90.0/security/sandbox/linux/launch/SandboxLaunch.cpp
+--- firefox-90.0.orig/security/sandbox/linux/launch/SandboxLaunch.cpp	2021-07-05 18:20:36.000000000 +0200
++++ firefox-90.0/security/sandbox/linux/launch/SandboxLaunch.cpp	2021-07-20 08:39:17.272136982 +0200
+@@ -501,8 +501,7 @@
+ MOZ_NEVER_INLINE MOZ_ASAN_BLACKLIST static pid_t DoClone(int aFlags,
+                                                          jmp_buf* aCtx) {
+   static constexpr size_t kStackAlignment = 16;
+-  uint8_t miniStack[PTHREAD_STACK_MIN]
+-      __attribute__((aligned(kStackAlignment)));
++  uint8_t miniStack[4096] __attribute__((aligned(kStackAlignment)));
+ #ifdef __hppa__
+   void* stackPtr = miniStack;
+ #else
+@@ -523,13 +522,19 @@
+                                CLONE_CHILD_CLEARTID;
+   MOZ_RELEASE_ASSERT((aFlags & kBadFlags) == 0);
+ 
++  // Block signals due to small stack in DoClone.
++  sigset_t oldSigs;
++  BlockAllSignals(&oldSigs);
++
++  int ret = 0;
+   jmp_buf ctx;
+   if (setjmp(ctx) == 0) {
+     // In the parent and just called setjmp:
+-    return DoClone(aFlags | SIGCHLD, &ctx);
++    ret = DoClone(aFlags | SIGCHLD, &ctx);
+   }
++  RestoreSignals(&oldSigs);
+   // In the child and have longjmp'ed:
+-  return 0;
++  return ret;
+ }
+ 
+ static bool WriteStringToFile(const char* aPath, const char* aStr,
+Only in firefox-90.0/security/sandbox/linux/launch: SandboxLaunch.cpp~
diff --git a/thunderbird.spec b/thunderbird.spec
index 8f15b11..1d7ce41 100644
--- a/thunderbird.spec
+++ b/thunderbird.spec
@@ -119,6 +119,7 @@ Patch417:       build-aarch64-user_vfp.patch
 Patch418:       mozilla-1512162.patch
 Patch419:       bindgen-d0dfc52706f23db9dc9d74642eeebd89d73cb8d0.patch
 Patch103:       rhbz-1219542-s390-build.patch
+Patch104:       firefox-glibc-dynstack.patch
 
 # PPC fix
 Patch304:       mozilla-1245783.patch
@@ -261,6 +262,7 @@ debug %{name}, you want to install %{name}-debuginfo instead.
 %ifarch s390
 %patch103 -p1 -b .rhbz-1219542-s390-build
 %endif
+%patch104 -p1 -b .dynstack
 
 %if 0%{?fedora} >= 35
 # since python3.10 we need to use  `from collections.abc` instead of `from collections`.