diff options
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/signal_32.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index e4ebe1a6228e..6b405a3f43f9 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -835,11 +835,21 @@ long sys_swapcontext(struct ucontext __user *old_ctx, return -EINVAL; if (old_ctx != NULL) { + struct mcontext __user *mctx; + + /* + * old_ctx might not be 16-byte aligned, in which + * case old_ctx->uc_mcontext won't be either. + * Because we have the old_ctx->uc_pad2 field + * before old_ctx->uc_mcontext, we need to round down + * from &old_ctx->uc_mcontext to a 16-byte boundary. + */ + mctx = (struct mcontext __user *) + ((unsigned long) &old_ctx->uc_mcontext & ~0xfUL); if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx)) - || save_user_regs(regs, &old_ctx->uc_mcontext, 0) + || save_user_regs(regs, mctx, 0) || put_sigset_t(&old_ctx->uc_sigmask, ¤t->blocked) - || __put_user(to_user_ptr(&old_ctx->uc_mcontext), - &old_ctx->uc_regs)) + || __put_user(to_user_ptr(mctx), &old_ctx->uc_regs)) return -EFAULT; } if (new_ctx == NULL) |