path: root/mm/memory-failure.c
diff options
authorMatthew Wilcox <willy@infradead.org>2018-11-30 11:05:06 -0500
committerDan Williams <dan.j.williams@intel.com>2018-12-04 21:32:00 -0800
commit27359fd6e5f3c5db8fe544b63238b6170e8806d8 (patch)
tree1f6bd40a9fdc8f43c76b97fe4eb0fa309d9f61d7 /mm/memory-failure.c
parentdax: Don't access a freed inode (diff)
dax: Fix unlock mismatch with updated API
Internal to dax_unlock_mapping_entry(), dax_unlock_entry() is used to store a replacement entry in the Xarray at the given xas-index with the DAX_LOCKED bit clear. When called, dax_unlock_entry() expects the unlocked value of the entry relative to the current Xarray state to be specified. In most contexts dax_unlock_entry() is operating in the same scope as the matched dax_lock_entry(). However, in the dax_unlock_mapping_entry() case the implementation needs to recall the original entry. In the case where the original entry is a 'pmd' entry it is possible that the pfn performed to do the lookup is misaligned to the value retrieved in the Xarray. Change the api to return the unlock cookie from dax_lock_page() and pass it to dax_unlock_page(). This fixes a bug where dax_unlock_page() was assuming that the page was PMD-aligned if the entry was a PMD entry with signatures like: WARNING: CPU: 38 PID: 1396 at fs/dax.c:340 dax_insert_entry+0x2b2/0x2d0 RIP: 0010:dax_insert_entry+0x2b2/0x2d0 [..] Call Trace: dax_iomap_pte_fault.isra.41+0x791/0xde0 ext4_dax_huge_fault+0x16f/0x1f0 ? up_read+0x1c/0xa0 __do_fault+0x1f/0x160 __handle_mm_fault+0x1033/0x1490 handle_mm_fault+0x18b/0x3d0 Link: https://lkml.kernel.org/r/20181130154902.GL10377@bombadil.infradead.org Fixes: 9f32d221301c ("dax: Convert dax_lock_mapping_entry to XArray") Reported-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Matthew Wilcox <willy@infradead.org> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to '')
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 0cd3de3550f0..7c72f2a95785 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1161,6 +1161,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
int rc = -EBUSY;
loff_t start;
+ dax_entry_t cookie;
* Prevent the inode from being freed while we are interrogating
@@ -1169,7 +1170,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
* also prevents changes to the mapping of this pfn until
* poison signaling is complete.
- if (!dax_lock_mapping_entry(page))
+ cookie = dax_lock_page(page);
+ if (!cookie)
goto out;
if (hwpoison_filter(page)) {
@@ -1220,7 +1222,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
rc = 0;
- dax_unlock_mapping_entry(page);
+ dax_unlock_page(page, cookie);
/* drop pgmap ref acquired in caller */