The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 142cd25293f6a7ecbdff4fb0af17de6438d46433 Mon Sep 17 00:00:00 2001
From: Al Viro viro@zeniv.linux.org.uk Date: Sun, 17 May 2020 15:37:50 -0400 Subject: [PATCH] sparc64: fix misuses of access_process_vm() in genregs32_[sg]et()
We do need access_process_vm() to access the target's reg_window. However, access to caller's memory (storing the result in genregs32_get(), fetching the new values in case of genregs32_set()) should be done by normal uaccess primitives.
Fixes: ad4f95764040 ([SPARC64]: Fix user accesses in regset code.) Cc: stable@kernel.org Signed-off-by: Al Viro viro@zeniv.linux.org.uk
diff --git a/arch/sparc/kernel/ptrace_64.c b/arch/sparc/kernel/ptrace_64.c index c9d41a96468f..3f5930bfab06 100644 --- a/arch/sparc/kernel/ptrace_64.c +++ b/arch/sparc/kernel/ptrace_64.c @@ -572,19 +572,13 @@ static int genregs32_get(struct task_struct *target, for (; count > 0 && pos < 32; count--) { if (access_process_vm(target, (unsigned long) - ®_window[pos], + ®_window[pos++], ®, sizeof(reg), FOLL_FORCE) != sizeof(reg)) return -EFAULT; - if (access_process_vm(target, - (unsigned long) u, - ®, sizeof(reg), - FOLL_FORCE | FOLL_WRITE) - != sizeof(reg)) + if (put_user(reg, u++)) return -EFAULT; - pos++; - u++; } } } @@ -684,12 +678,7 @@ static int genregs32_set(struct task_struct *target, } } else { for (; count > 0 && pos < 32; count--) { - if (access_process_vm(target, - (unsigned long) - u, - ®, sizeof(reg), - FOLL_FORCE) - != sizeof(reg)) + if (get_user(reg, u++)) return -EFAULT; if (access_process_vm(target, (unsigned long)