The patch titled nommu: fix race between ramfs truncation and shared mmap has been removed from the -mm tree. Its filename was nommu-fix-race-between-ramfs-truncation-and-shared-mmap.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: nommu: fix race between ramfs truncation and shared mmap From: David Howells <dhowells@xxxxxxxxxx> Fix the race between the truncation of a ramfs file and an attempt to make a shared mmap of region of that file. The problem is that do_mmap_pgoff() calls f_op->get_unmapped_area() to verify that the file region is made of contiguous pages and to find its base address - but there isn't any locking to guarantee this region until vma_prio_tree_insert() is called by add_vma_to_mm(). Note that moving the functionality into f_op->mmap() doesn't help as that is also called before vma_prio_tree_insert(). Instead make ramfs_nommu_check_mappings() grab nommu_region_sem whilst it does its checks. This means that this function will wait whilst mmaps take place. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Greg Ungerer <gerg@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/ramfs/file-nommu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff -puN fs/ramfs/file-nommu.c~nommu-fix-race-between-ramfs-truncation-and-shared-mmap fs/ramfs/file-nommu.c --- a/fs/ramfs/file-nommu.c~nommu-fix-race-between-ramfs-truncation-and-shared-mmap +++ a/fs/ramfs/file-nommu.c @@ -131,6 +131,8 @@ static int ramfs_nommu_check_mappings(st struct vm_area_struct *vma; struct prio_tree_iter iter; + down_write(&nommu_region_sem); + /* search for VMAs that fall within the dead zone */ vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, newsize >> PAGE_SHIFT, @@ -138,10 +140,13 @@ static int ramfs_nommu_check_mappings(st ) { /* found one - only interested if it's shared out of the page * cache */ - if (vma->vm_flags & VM_SHARED) + if (vma->vm_flags & VM_SHARED) { + up_write(&nommu_region_sem); return -ETXTBSY; /* not quite true, but near enough */ + } } + up_write(&nommu_region_sem); return 0; } _ Patches currently in -mm which might be from dhowells@xxxxxxxxxx are origin.patch linux-next.patch kernel-credc-use-kmem_cache_free.patch frv-duplicate-output_buffer-of-e03.patch coredump-unify-dump_seek-implementations-for-each-binfmt_c.patch coredump-move-dump_write-and-dump_seek-into-a-header-file.patch elf-coredump-replace-elf_core_extra_-macros-by-functions.patch elf-coredump-make-offset-calculation-process-and-writing-process-explicit.patch elf-coredump-add-extended-numbering-support.patch mutex-subsystem-synchro-test-module.patch mutex-subsystem-synchro-test-module-add-missing-header-file.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html