From e6c9366b2adb52cba64b359b3050200743c7568c Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 20 May 2011 15:47:33 -0700 Subject: [PATCH] tmpfs: fix highmem swapoff crash regression Commit 778dd893ae78 ("tmpfs: fix race between umount and swapoff") forgot the new rules for strict atomic kmap nesting, causing WARNING: at arch/x86/mm/highmem_32.c:81 from __kunmap_atomic(), then BUG: unable to handle kernel paging request at fffb9000 from shmem_swp_set() when shmem_unuse_inode() is handling swapoff with highmem in use. My disgrace again. See https://bugzilla.kernel.org/show_bug.cgi?id=35352 Reported-by: Witold Baryluk Signed-off-by: Hugh Dickins Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- mm/shmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index dfc7069..ba4ad28 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -916,11 +916,12 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s if (size > ENTRIES_PER_PAGE) size = ENTRIES_PER_PAGE; offset = shmem_find_swp(entry, ptr, ptr+size); + shmem_swp_unmap(ptr); if (offset >= 0) { shmem_dir_unmap(dir); + ptr = shmem_swp_map(subdir); goto found; } - shmem_swp_unmap(ptr); } } lost1: -- 2.7.4