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authorTejun Heo <tj@kernel.org>2013-10-14 13:27:11 (GMT)
committerPawel Osmialowski <p.osmialowsk@mcdsrvbld02.digital.local>2015-03-27 13:37:25 (GMT)
commit2338f3cf7b0b08fde3877a3092ccebaf05551a84 (patch)
tree112cc1bd3bd4e5e3ba104d933a6a206351c24728
parent011351985c3fef7726ab527f8a70d126d691e49a (diff)
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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>
-rw-r--r--fs/sysfs/dir.c22
-rw-r--r--fs/sysfs/file.c3
-rw-r--r--fs/sysfs/sysfs.h20
3 files changed, 22 insertions, 23 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index dd516c4..92de88d 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -132,24 +132,6 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
}
-#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
@@ -168,7 +150,7 @@ 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;
}
@@ -187,7 +169,7 @@ 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 04dcfbd..6f05e3e 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 1c6dc6c..3875086 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; \
@@ -111,9 +112,24 @@ do { \
key = &attr->skey; \
\
lockdep_init_map(&sd->dep_map, "s_active", key, 0); \
-} while(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)
+
+#define sysfs_dirent_init_lockdep(sd) do {} while (0)
+
+static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
+{
+ return true;
+}
+
#endif
/*