The current interface copy_oldmem_page() passes user pointer without __user annotation and hence does unnecessary user/kernel pointer conversions during its implementation.
Use the interface copy_oldmem_page_buf() to avoid this issue. Cc: Paul Walmsley <[email protected]> Cc: Palmer Dabbelt <[email protected]> Cc: Albert Ou <[email protected]> Cc: linux-riscv <[email protected]> Signed-off-by: Amit Daniel Kachhap <[email protected]> --- arch/riscv/kernel/crash_dump.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c index 86cc0ada5752..3a8fadcd1278 100644 --- a/arch/riscv/kernel/crash_dump.c +++ b/arch/riscv/kernel/crash_dump.c @@ -9,20 +9,21 @@ #include <linux/io.h> /** - * copy_oldmem_page() - copy one page from old kernel memory + * copy_oldmem_page_buf() - copy one page from old kernel memory * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed + * @ubuf: user buffer where the copied page is placed; use copy_to_user() if + * this pointer is not NULL + * @kbuf: kernel buffer where the copied page is placed; use memcpy() if this + * pointer is not NULL * @csize: number of bytes to copy * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. + * This function copies one page from old kernel memory into the buffer pointed + * by either @ubuf or @kbuf. Returns number of bytes copied or negative error in + * case of failure. */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { void *vaddr; @@ -33,13 +34,13 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { + if (ubuf) { + if (copy_to_user(ubuf, vaddr + offset, csize)) { memunmap(vaddr); return -EFAULT; } } else - memcpy(buf, vaddr + offset, csize); + memcpy(kbuf, vaddr + offset, csize); memunmap(vaddr); return csize; -- 2.17.1 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
