diff options
Diffstat (limited to 'fs/proc/vmcore.c')
| -rw-r--r-- | fs/proc/vmcore.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 30a3b66f475a..702754dd1daf 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -65,8 +65,6 @@ static size_t vmcoredd_orig_sz; static DECLARE_RWSEM(vmcore_cb_rwsem); /* List of registered vmcore callbacks. */ static LIST_HEAD(vmcore_cb_list); -/* Whether we had a surprise unregistration of a callback. */ -static bool vmcore_cb_unstable; /* Whether the vmcore has been opened once. */ static bool vmcore_opened; @@ -94,10 +92,8 @@ void unregister_vmcore_cb(struct vmcore_cb *cb) * very unusual (e.g., forced driver removal), but we cannot stop * unregistering. */ - if (vmcore_opened) { + if (vmcore_opened) pr_warn_once("Unexpected vmcore callback unregistration\n"); - vmcore_cb_unstable = true; - } up_write(&vmcore_cb_rwsem); } EXPORT_SYMBOL_GPL(unregister_vmcore_cb); @@ -108,8 +104,6 @@ static bool pfn_is_ram(unsigned long pfn) bool ret = true; lockdep_assert_held_read(&vmcore_cb_rwsem); - if (unlikely(vmcore_cb_unstable)) - return false; list_for_each_entry(cb, &vmcore_cb_list, next) { if (unlikely(!cb->pfn_is_ram)) @@ -154,9 +148,13 @@ 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)) - memset(buf, 0, nr_bytes); - else { + if (!pfn_is_ram(pfn)) { + 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, @@ -165,12 +163,12 @@ ssize_t read_from_oldmem(char *buf, size_t count, else tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf); - - if (tmp < 0) { - up_read(&vmcore_cb_rwsem); - return tmp; - } } + if (tmp < 0) { + up_read(&vmcore_cb_rwsem); + return tmp; + } + *ppos += nr_bytes; count -= nr_bytes; buf += nr_bytes; @@ -577,7 +575,7 @@ static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma, * looping over all pages without a reason. */ down_read(&vmcore_cb_rwsem); - if (!list_empty(&vmcore_cb_list) || vmcore_cb_unstable) + if (!list_empty(&vmcore_cb_list)) ret = remap_oldmem_pfn_checked(vma, from, pfn, size, prot); else ret = remap_oldmem_pfn_range(vma, from, pfn, size, prot); |