X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Famd64-linux-nat.c;h=d0328b677d598456909c817c6e9969dc9961645f;hb=e671856cb804c977650aaeb4107948a7b963e9e9;hp=4f1c98a0d1e17125b02d64453230eb6e06989aa5;hpb=268a13a5a3f7c6b9b6ffc5ac2d1b24eb41f3fbdc;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index 4f1c98a0d1..d0328b677d 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -238,6 +238,12 @@ amd64_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
 	  char xstateregs[X86_XSTATE_MAX_SIZE];
 	  struct iovec iov;
 
+	  /* Pre-4.14 kernels have a bug (fixed by commit 0852b374173b
+	     "x86/fpu: Add FPU state copying quirk to handle XRSTOR failure on
+	     Intel Skylake CPUs") that sometimes causes the mxcsr location in
+	     xstateregs not to be copied by PTRACE_GETREGSET.  Make sure that
+	     the location is at least initialized with a defined value.  */
+	  memset (xstateregs, 0, sizeof (xstateregs));
 	  iov.iov_base = xstateregs;
 	  iov.iov_len = sizeof (xstateregs);
 	  if (ptrace (PTRACE_GETREGSET, tid,