kernfs_unmap_bin_file() is supposed to unmap all memory mappings of the target file before kernfs_remove() finishes; however, it currently is being called from kernfs_addrm_finish() and has the same race problem as the original implementation of deactivation when there are multiple removers - only the remover which snatches the node to its addrm_cxt->removed list is guaranteed to wait for its completion before returning.
It can be easily fixed by moving kernfs_unmap_bin_file() invocation from kernfs_addrm_finish() to kernfs_deactivated(). The function may be called multiple times but that shouldn't do any harm. Signed-off-by: Tejun Heo <t...@kernel.org> --- fs/kernfs/dir.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index a73caa6..ff633d2 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -177,9 +177,10 @@ void kernfs_put_active(struct kernfs_node *kn) * kernfs_deactivate - deactivate kernfs_node * @kn: kernfs_node to deactivate * - * Deny new active references and drain existing ones. Mutiple - * removers may invoke this function concurrently on @kn and all will - * return after deactivation and draining are complete. + * Deny new active references, drain existing ones and nuke all + * existing mmaps. Mutiple removers may invoke this function + * concurrently on @kn and all will return after deactivation and + * draining are complete. */ static void kernfs_deactivate(struct kernfs_node *kn) __releases(&kernfs_mutex) __acquires(&kernfs_mutex) @@ -209,6 +210,8 @@ static void kernfs_deactivate(struct kernfs_node *kn) lock_acquired(&kn->dep_map, _RET_IP_); rwsem_release(&kn->dep_map, 1, _RET_IP_); + kernfs_unmap_bin_file(kn); + mutex_lock(&kernfs_mutex); } @@ -477,7 +480,6 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt) acxt->removed = kn->u.removed_list; - kernfs_unmap_bin_file(kn); kernfs_put(kn); } } -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/