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authorTejun Heo <tj@kernel.org>2013-10-14 09:27:11 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-14 08:40:39 -0700
commit785a162d147a547bc7a577c1c28f6fb9dbeb4f16 (patch)
treebb3b2905f625b4974c1ab5a2972f98807d44b61e /fs/sysfs
parent1461c5be7becc6e65dba5cadb31fb5f4339609f5 (diff)
sysfs: make sysfs_file_ops() follow ignore_lockdep flag
375b611e60 ("sysfs: remove sysfs_buffer->ops") introduced sysfs_file_ops() which determines the associated file operation of a given sysfs_dirent. As file ops access should be protected by an active reference, the new function includes a lockdep assertion on the sysfs_dirent; unfortunately, I forgot to take attr->ignore_lockdep flag into account and the lockdep assertion trips spuriously for files which opt out from active reference lockdep checking. # cat /sys/devices/pci0000:00/0000:00:01.2/usb1/authorized ------------[ cut here ]------------ WARNING: CPU: 1 PID: 540 at /work/os/work/fs/sysfs/file.c:79 sysfs_file_ops+0x4e/0x60() Modules linked in: CPU: 1 PID: 540 Comm: cat Not tainted 3.11.0-work+ #3 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000009 ffff880016205c08 ffffffff81ca0131 0000000000000000 ffff880016205c40 ffffffff81096d0d ffff8800166cb898 ffff8800166f6f60 ffffffff8125a220 ffff880011ab1ec0 ffff88000aff0c78 ffff880016205c50 Call Trace: [<ffffffff81ca0131>] dump_stack+0x4e/0x82 [<ffffffff81096d0d>] warn_slowpath_common+0x7d/0xa0 [<ffffffff81096dea>] warn_slowpath_null+0x1a/0x20 [<ffffffff8125994e>] sysfs_file_ops+0x4e/0x60 [<ffffffff8125a274>] sysfs_open_file+0x54/0x300 [<ffffffff811df612>] do_dentry_open.isra.17+0x182/0x280 [<ffffffff811df820>] finish_open+0x30/0x40 [<ffffffff811f0623>] do_last+0x503/0xd90 [<ffffffff811f0f6b>] path_openat+0xbb/0x6d0 [<ffffffff811f23ba>] do_filp_open+0x3a/0x90 [<ffffffff811e09a9>] do_sys_open+0x129/0x220 [<ffffffff811e0abe>] SyS_open+0x1e/0x20 [<ffffffff81caf3c2>] system_call_fastpath+0x16/0x1b ---[ end trace aa48096b111dafdb ]--- Rename fs/sysfs/dir.c::ignore_lockdep() to sysfs_ignore_lockdep() and move it to fs/sysfs/sysfs.h and make sysfs_file_ops() skip lockdep assertion if sysfs_ignore_lockdep() is true. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/sysfs')
-rw-r--r--fs/sysfs/dir.c22
-rw-r--r--fs/sysfs/file.c3
-rw-r--r--fs/sysfs/sysfs.h16
3 files changed, 20 insertions, 21 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index f6025c81bfd5..eab59de47556 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -144,24 +144,6 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
sd->s_parent->s_flags &= ~SYSFS_FLAG_HAS_NS;
}
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-
-/* Test for attributes that want to ignore lockdep for read-locking */
-static bool ignore_lockdep(struct sysfs_dirent *sd)
-{
- return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
- sd->s_attr.attr->ignore_lockdep;
-}
-
-#else
-
-static inline bool ignore_lockdep(struct sysfs_dirent *sd)
-{
- return true;
-}
-
-#endif
-
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
@@ -180,7 +162,7 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
if (!atomic_inc_unless_negative(&sd->s_active))
return NULL;
- if (likely(!ignore_lockdep(sd)))
+ if (likely(!sysfs_ignore_lockdep(sd)))
rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
return sd;
}
@@ -199,7 +181,7 @@ void sysfs_put_active(struct sysfs_dirent *sd)
if (unlikely(!sd))
return;
- if (likely(!ignore_lockdep(sd)))
+ if (likely(!sysfs_ignore_lockdep(sd)))
rwsem_release(&sd->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&sd->s_active);
if (likely(v != SD_DEACTIVATED_BIAS))
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 5f7a955550de..c324ee906df0 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -76,7 +76,8 @@ static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
{
struct kobject *kobj = sd->s_parent->s_dir.kobj;
- lockdep_assert_held(sd);
+ if (!sysfs_ignore_lockdep(sd))
+ lockdep_assert_held(sd);
return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
}
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 4e01d3b3909c..94ac8fa34dd4 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -103,6 +103,7 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
#define sysfs_dirent_init_lockdep(sd) \
do { \
struct attribute *attr = sd->s_attr.attr; \
@@ -112,8 +113,23 @@ do { \
\
lockdep_init_map(&sd->dep_map, "s_active", key, 0); \
} while (0)
+
+/* Test for attributes that want to ignore lockdep for read-locking */
+static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
+{
+ return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
+ sd->s_attr.attr->ignore_lockdep;
+}
+
#else
+
#define sysfs_dirent_init_lockdep(sd) do {} while (0)
+
+static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
+{
+ return true;
+}
+
#endif
/*