Re: [PATCH 1/3] lockdep: Move lock events under lockdep recursionprotection

From: Frederic Weisbecker
Date: Tue Mar 09 2010 - 19:05:46 EST


On Tue, Mar 09, 2010 at 09:35:37AM +0100, Jens Axboe wrote:
> Which, btw, throws a new lockdep warning fest:
>
> [ 42.247718] scsi7 : ioc0: LSISAS1068E B3, FwRev=011b0300h, Ports=1, MaxQ=483, IRQ=26
> [ 42.281125] BUG: key ffff880c7cb75250 not in .data!
> [ 42.288346] ------------[ cut here ]------------
> [ 42.294490] WARNING: at kernel/lockdep.c:2706 lockdep_init_map+0x545/0x5f0()
> [ 42.304013] Hardware name: QSSC-S4R
> [ 42.309674] Modules linked in: hid_apple usbhid ehci_hcd uhci_hcd usbcore nls_base mptsas(+) mptscsih mptbase scsi_transport_sas igb sg sr_mod cdrom
> [ 42.332072] Pid: 5197, comm: modprobe Not tainted 2.6.34-rc1 #176
> [ 42.340597] Call Trace:
> [ 42.345335] [<ffffffff8107fb8d>] ? is_module_address+0x2d/0x60
> [ 42.353670] [<ffffffff81074aa5>] ? lockdep_init_map+0x545/0x5f0
> [ 42.362154] [<ffffffff81044648>] warn_slowpath_common+0x78/0xd0
> [ 42.371913] [<ffffffff810446af>] warn_slowpath_null+0xf/0x20
> [ 42.380109] [<ffffffff81074aa5>] lockdep_init_map+0x545/0x5f0



This doesn't look related to my patch, it also happen in -rc1 right?



> [ 42.388402] [<ffffffff81156636>] ? sysfs_new_dirent+0x76/0x120


This calls:

#define sysfs_dirent_init_lockdep(sd) \
do { \
struct attribute *attr = sd->s_attr.attr; \
struct lock_class_key *key = attr->key; \
if (!key) \
key = &attr->skey; \
\
lockdep_init_map(&sd->dep_map, "s_active", key, 0); \
} while(0)


Looks like the struct lock_class_key is dynamically allocated
and lockdep doesn't like that.

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