PR gdb/15236: gdbserver write to linux memory with zero length corrupts stack

[deliverable/binutils-gdb.git] / gdb / gdbserver / linux-low.c

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index c52cd2e165a39a989de21e21e6648dea517aa019..5f036284a92719f9dcfda3556036ce5af3ab4e3a 100644 (file)
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4481,7 +4481,7 @@ linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 
 /* Copy LEN bytes of data from debugger memory at MYADDR to inferior's
    memory at MEMADDR.  On failure (cannot write to the inferior)
-   returns the value of errno.  */
+   returns the value of errno.  Always succeeds if LEN is zero.  */
 
 static int
 linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
@@ -4500,6 +4500,12 @@ linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 
   int pid = lwpid_of (get_thread_lwp (current_inferior));
 
+  if (len == 0)
+    {
+      /* Zero length write always succeeds.  */
+      return 0;
+    }
+
   if (debug_threads)
     {
       /* Dump up to four bytes.  */