Merge tag 'mmc-v5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc

[linux-2.6-microblaze.git] / fs / proc / kcore.c

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 4d2e64e..982e694 100644 (file)
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -313,6 +313,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 {
        char *buf = file->private_data;
        size_t phdrs_offset, notes_offset, data_offset;
+       size_t page_offline_frozen = 1;
        size_t phdrs_len, notes_len;
        struct kcore_list *m;
        size_t tsz;
@@ -322,6 +323,11 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
        int ret = 0;
 
        down_read(&kclist_lock);
+       /*
+        * Don't race against drivers that set PageOffline() and expect no
+        * further page access.
+        */
+       page_offline_freeze();
 
        get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
        phdrs_offset = sizeof(struct elfhdr);
@@ -380,11 +386,8 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
                        phdr->p_type = PT_LOAD;
                        phdr->p_flags = PF_R | PF_W | PF_X;
                        phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
-                       if (m->type == KCORE_REMAP)
-                               phdr->p_vaddr = (size_t)m->vaddr;
-                       else
-                               phdr->p_vaddr = (size_t)m->addr;
-                       if (m->type == KCORE_RAM || m->type == KCORE_REMAP)
+                       phdr->p_vaddr = (size_t)m->addr;
+                       if (m->type == KCORE_RAM)
                                phdr->p_paddr = __pa(m->addr);
                        else if (m->type == KCORE_TEXT)
                                phdr->p_paddr = __pa_symbol(m->addr);
@@ -468,6 +471,9 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 
        m = NULL;
        while (buflen) {
+               struct page *page;
+               unsigned long pfn;
+
                /*
                 * If this is the first iteration or the address is not within
                 * the previous entry, search for a matching entry.
@@ -480,31 +486,57 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
                        }
                }
 
+               if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
+                       page_offline_thaw();
+                       cond_resched();
+                       page_offline_freeze();
+               }
+
                if (&m->list == &kclist_head) {
                        if (clear_user(buffer, tsz)) {
                                ret = -EFAULT;
                                goto out;
                        }
                        m = NULL;       /* skip the list anchor */
-               } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
-                       if (clear_user(buffer, tsz)) {
-                               ret = -EFAULT;
-                               goto out;
-                       }
-               } else if (m->type == KCORE_VMALLOC) {
+                       goto skip;
+               }
+
+               switch (m->type) {
+               case KCORE_VMALLOC:
                        vread(buf, (char *)start, tsz);
                        /* we have to zero-fill user buffer even if no read */
                        if (copy_to_user(buffer, buf, tsz)) {
                                ret = -EFAULT;
                                goto out;
                        }
-               } else if (m->type == KCORE_USER) {
+                       break;
+               case KCORE_USER:
                        /* User page is handled prior to normal kernel page: */
                        if (copy_to_user(buffer, (char *)start, tsz)) {
                                ret = -EFAULT;
                                goto out;
                        }
-               } else {
+                       break;
+               case KCORE_RAM:
+                       pfn = __pa(start) >> PAGE_SHIFT;
+                       page = pfn_to_online_page(pfn);
+
+                       /*
+                        * Don't read offline sections, logically offline pages
+                        * (e.g., inflated in a balloon), hwpoisoned pages,
+                        * and explicitly excluded physical ranges.
+                        */
+                       if (!page || PageOffline(page) ||
+                           is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
+                               if (clear_user(buffer, tsz)) {
+                                       ret = -EFAULT;
+                                       goto out;
+                               }
+                               break;
+                       }
+                       fallthrough;
+               case KCORE_VMEMMAP:
+               case KCORE_TEXT:
                        if (kern_addr_valid(start)) {
                                /*
                                 * Using bounce buffer to bypass the
@@ -528,7 +560,15 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
                                        goto out;
                                }
                        }
+                       break;
+               default:
+                       pr_warn_once("Unhandled KCORE type: %d\n", m->type);
+                       if (clear_user(buffer, tsz)) {
+                               ret = -EFAULT;
+                               goto out;
+                       }
                }
+skip:
                buflen -= tsz;
                *fpos += tsz;
                buffer += tsz;
@@ -537,6 +577,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
        }
 
 out:
+       page_offline_thaw();
        up_read(&kclist_lock);
        if (ret)
                return ret;