This is a note to let you know that I've just added the patch titled um: Fix PTRACE_POKEUSER on x86_64 to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: um-fix-ptrace_pokeuser-on-x86_64.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 9abc74a22d85ab29cef9896a2582a530da7e79bf Mon Sep 17 00:00:00 2001 From: Richard Weinberger <richard@xxxxxx> Date: Sat, 1 Apr 2017 00:41:57 +0200 Subject: um: Fix PTRACE_POKEUSER on x86_64 From: Richard Weinberger <richard@xxxxxx> commit 9abc74a22d85ab29cef9896a2582a530da7e79bf upstream. This is broken since ever but sadly nobody noticed. Recent versions of GDB set DR_CONTROL unconditionally and UML dies due to a heap corruption. It turns out that the PTRACE_POKEUSER was copy&pasted from i386 and assumes that addresses are 4 bytes long. Fix that by using 8 as address size in the calculation. Reported-by: jie cao <cj3054@xxxxxxxxx> Signed-off-by: Richard Weinberger <richard@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/um/ptrace_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, else if ((addr >= offsetof(struct user, u_debugreg[0])) && (addr <= offsetof(struct user, u_debugreg[7]))) { addr -= offsetof(struct user, u_debugreg[0]); - addr = addr >> 2; + addr = addr >> 3; if ((addr == 4) || (addr == 5)) return -EIO; child->thread.arch.debugregs[addr] = data; Patches currently in stable-queue which might be from richard@xxxxxx are queue-4.11/um-fix-ptrace_pokeuser-on-x86_64.patch