From: Jan H. Schönherr <jschoenh@xxxxxxxxx> [ Upstream commit ee190ca6516bc8257e3d36187ca6f0f71a9ec477 ] follow_pte_pmd() can theoretically return after having acquired a PMD lock, even when DAX was not compiled with CONFIG_FS_DAX_PMD. Release the PMD lock unconditionally. Link: http://lkml.kernel.org/r/20180118133839.20587-1-jschoenh@xxxxxxxxx Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean") Signed-off-by: Jan H. Schönherr <jschoenh@xxxxxxxxx> Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> --- fs/dax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index 95981591977a..c2ebf10b70da 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -636,8 +636,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping, pmd = pmd_mkclean(pmd); set_pmd_at(vma->vm_mm, address, pmdp, pmd); unlock_pmd: - spin_unlock(ptl); #endif + spin_unlock(ptl); } else { if (pfn != pte_pfn(*ptep)) goto unlock_pte; -- 2.15.1