From 785a162d147a547bc7a577c1c28f6fb9dbeb4f16 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Oct 2013 09:27:11 -0400 Subject: 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: [] dump_stack+0x4e/0x82 [] warn_slowpath_common+0x7d/0xa0 [] warn_slowpath_null+0x1a/0x20 [] sysfs_file_ops+0x4e/0x60 [] sysfs_open_file+0x54/0x300 [] do_dentry_open.isra.17+0x182/0x280 [] finish_open+0x30/0x40 [] do_last+0x503/0xd90 [] path_openat+0xbb/0x6d0 [] do_filp_open+0x3a/0x90 [] do_sys_open+0x129/0x220 [] SyS_open+0x1e/0x20 [] 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 Reported-by: Yinghai Lu Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/sysfs/file.c') 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; } -- cgit v1.2.3