Kernel: Only unlock Mutex once in execve when PT_TRACE_ME is enabled

Fixes a regression introduced in 70518e6. Fixes #9704.
Author: https://github.com/ADKaster Commit: https://github.com/SerenityOS/serenity/commit/fcdd7aa9909 Pull-request: https://github.com/SerenityOS/serenity/pull/9715 Issue: https://github.com/SerenityOS/serenity/issues/9704
2021-08-31 18:57:42 -06:00 · 2021-08-31 18:57:42 -06:00 · fcdd7aa990 · 2024-07-18 04:58:43 +09:00
commit fcdd7aa990
parent 33d7fdca28
1 changed files with 4 additions and 1 deletions
--- a/Kernel/Syscalls/execve.cpp
+++ b/Kernel/Syscalls/execve.cpp
@ -628,8 +628,11 @@ KResult Process::do_exec(NonnullRefPtr<FileDescription> main_program_description
        // Make sure we release the ptrace lock here or the tracer will block forever.
        ptrace_locker.unlock();
        Thread::current()->send_urgent_signal_to_self(SIGSTOP);
+    } else {
+        // Unlock regardless before disabling interrupts.
+        // Ensure we always unlock after checking ptrace status to avoid TOCTOU ptrace issues
+        ptrace_locker.unlock();
    }
-    ptrace_locker.unlock(); // unlock before disabling interrupts as well

    // We enter a critical section here because we don't want to get interrupted between do_exec()
    // and Processor::assume_context() or the next context switch.