The patch titled
Subject: mm-fix-xip-fault-vs-truncate-race-fix
has been added to the -mm tree. Its filename is
mm-fix-xip-fault-vs-truncate-race-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-xip-fault-vs-truncate-race-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-xip-fault-vs-truncate-race-fix.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-fix-xip-fault-vs-truncate-race-fix
switch to i_mmap_lock_read(), add comment in unmap_single_vma()
Cc: Jan Kara <jack@xxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Andreas Dilger <andreas.dilger@xxxxxxxxx>
Cc: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap_xip.c | 20 +++++++++++++-------
mm/memory.c | 5 +++++
2 files changed, 18 insertions(+), 7 deletions(-)
diff -puN mm/filemap_xip.c~mm-fix-xip-fault-vs-truncate-race-fix mm/filemap_xip.c
--- a/mm/filemap_xip.c~mm-fix-xip-fault-vs-truncate-race-fix
+++ a/mm/filemap_xip.c
@@ -255,17 +255,20 @@ again:
__xip_unmap(mapping, vmf->pgoff);
found:
- /* We must recheck i_size under i_mmap_mutex */
- mutex_lock(&mapping->i_mmap_mutex);
+ /*
+ * We must recheck i_size under i_mmap_rwsem to prevent races
+ * with truncation
+ */
+ i_mmap_lock_read(mapping);
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
if (unlikely(vmf->pgoff >= size)) {
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_read(mapping);
return VM_FAULT_SIGBUS;
}
err = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address,
xip_pfn);
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_read(mapping);
if (err == -ENOMEM)
return VM_FAULT_OOM;
/*
@@ -290,8 +293,11 @@ found:
if (error != -ENODATA)
goto out;
- /* We must recheck i_size under i_mmap_mutex */
- mutex_lock(&mapping->i_mmap_mutex);
+ /*
+ * We must recheck i_size under i_mmap_rwsem to prevent races
+ * with truncation
+ */
+ i_mmap_lock_read(mapping);
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
if (unlikely(vmf->pgoff >= size)) {
@@ -309,7 +315,7 @@ found:
ret = VM_FAULT_NOPAGE;
unlock:
- mutex_unlock(&mapping->i_mmap_mutex);
+ i_mmap_unlock_read(mapping);
out:
write_seqcount_end(&xip_sparse_seq);
mutex_unlock(&xip_sparse_mutex);
diff -puN mm/memory.c~mm-fix-xip-fault-vs-truncate-race-fix mm/memory.c
--- a/mm/memory.c~mm-fix-xip-fault-vs-truncate-race-fix
+++ a/mm/memory.c
@@ -1327,6 +1327,11 @@ static void unmap_single_vma(struct mmu_
* safe to do nothing in this case.
*/
if (vma->vm_file) {
+ /*
+ * Note that DAX uses i_mmap_lock to serialise
+ * against file truncate - truncate calls into
+ * unmap_single_vma().
+ */
i_mmap_lock_write(vma->vm_file->f_mapping);
__unmap_hugepage_range_final(tlb, vma, start, end, NULL);
i_mmap_unlock_write(vma->vm_file->f_mapping);
_
Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
i-need-old-gcc.patch
arch-alpha-kernel-systblss-remove-debug-check.patch
fanotify-dont-recalculate-a-marks-mask-if-only-the-ignored-mask-changed-checkpatch-fixes.patch
fanotify-dont-set-fan_ondir-implicitly-on-a-marks-ignored-mask-checkpatch-fixes.patch
input-route-kbd-leds-through-the-generic-leds-layer.patch
o2dlm-fix-null-pointer-dereference-in-o2dlm_blocking_ast_wrapper.patch
ocfs2-add-functions-to-add-and-remove-inode-in-orphan-dir.patch
mm.patch
mm-fix-xip-fault-vs-truncate-race-fix.patch
mm-allow-page-fault-handlers-to-perform-the-cow-fix.patch
daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler-fix.patch
dax-add-dax_zero_page_range-fix.patch
mm-replace-remap_file_pages-syscall-with-emulation.patch
mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask.patch
x86-add-pmd_-for-thp-fix.patch
sparc-add-pmd_-for-thp-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
task_mmu-add-user-space-support-for-resetting-mm-hiwater_rss-peak-rss.patch
lib-bitmap-update-bitmap_onto-to-unsigned-checkpatch-fixes.patch
lib-bitmap-change-parameters-of-bitmap_fold-to-unsigned-fix.patch
hexdump-makes-it-return-amount-of-bytes-placed-in-buffer-fix.patch
fs-befs-linuxvfsc-remove-unnecessary-casting-fix.patch
linux-next.patch
drivers-gpio-gpio-zevioc-fix-build.patch
journal_add_journal_head-debug.patch
journal_add_journal_head-debug-fix.patch
kernel-forkc-export-kernel_thread-to-modules.patch
mutex-subsystem-synchro-test-module.patch
slab-leaks3-default-y.patch
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