diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index c3a345c28a93..0e4278d4a769 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -124,9 +124,13 @@ ssize_t read_from_oldmem(char *buf, size_t count, nr_bytes = count; /* If pfn is not ram, return zeros for sparse dump files */ - if (pfn_is_ram(pfn) == 0) - memset(buf, 0, nr_bytes); - else { + if (pfn_is_ram(pfn) == 0) { + tmp = 0; + if (!userbuf) + memset(buf, 0, nr_bytes); + else if (clear_user(buf, nr_bytes)) + tmp = -EFAULT; + } else { if (encrypted) tmp = copy_oldmem_page_encrypted(pfn, buf, nr_bytes, @@ -135,10 +139,10 @@ ssize_t read_from_oldmem(char *buf, size_t count, else tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf); - - if (tmp < 0) - return tmp; } + if (tmp < 0) + return tmp; + *ppos += nr_bytes; count -= nr_bytes; buf += nr_bytes;