[PATCH] tmpfs: fix highmem swapoff crash regression
From: Hugh Dickins
Date: Fri May 20 2011 - 18:47:50 EST
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 <baryluk@xxxxxxxxxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---
mm/shmem.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 2.6.39/mm/shmem.c 2011-05-18 21:06:34.000000000 -0700
+++ linux/mm/shmem.c 2011-05-20 13:57:20.778870967 -0700
@@ -916,11 +916,12 @@ static int shmem_unuse_inode(struct shme
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:
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