Fix a commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") bug and allow the last register requested with a ptrace(2) PTRACE_SETREGSET call to be partially written if supplied this way by the caller, like with other register sets.
Cc: stable@vger.kernel.org # v4.11+ Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") Signed-off-by: Maciej W. Rozycki macro@mips.com --- arch/mips/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
linux-mips-nt-prfpreg-count.diff Index: linux-sfr-test/arch/mips/kernel/ptrace.c =================================================================== --- linux-sfr-test.orig/arch/mips/kernel/ptrace.c 2017-11-21 22:12:00.000000000 +0000 +++ linux-sfr-test/arch/mips/kernel/ptrace.c 2017-11-21 22:13:13.471970000 +0000 @@ -484,7 +484,7 @@ static int fpr_set_msa(struct task_struc int err;
BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t)); - for (i = 0; i < NUM_FPU_REGS && *count >= sizeof(elf_fpreg_t); i++) { + for (i = 0; i < NUM_FPU_REGS && *count > 0; i++) { err = user_regset_copyin(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t));