Driver core patches for kernel 3.14
Subsystems (2)
cover Driver core patches for kernel 3.14
This series consists of the following three patches:
0001-kobject-Fix-source-code-comment-spelling.patch 0002-firmware-loader-Add-sparse-annotation.patch 0003-driver-core-Fix-use-after-free-triggered-by-bus_unre.patch
PATCH 1/3 kobject: Fix source code comment spelling
--- lib/kobject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
lib/kobject.c +1 -1
@@ -346,7 +346,7 @@ static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,* * If @parent is set, then the parent of the @kobj will be set to it. * If @parent is NULL, then the parent of the @kobj will be set to the -* kobject associted with the kset assigned to this kobject. If no kset +* kobject associated with the kset assigned to this kobject. If no kset * is assigned to the kobject, then the kobject will be located in the * root of the sysfs tree. *
Signature · 1 line
1.8.1.4
PATCH 2/3 firmware loader: Add sparse annotation
In reply to Bart Van AsscheAvoid that sparse reports the following warning on __fw_free_buf():
drivers/base/firmware_class.c:230:9: warning: context imbalance in '__fw_free_buf' - unexpected unlock
--- drivers/base/firmware_class.c | 1 + 1 file changed, 1 insertion(+)
drivers/base/firmware_class.c +1 -0
@@ -219,6 +219,7 @@ static int fw_lookup_and_allocate_buf(const char *fw_name, }static void __fw_free_buf (struct kref *ref) + __releases(&fwc->lock) {struct firmware_buf *buf =to_fwbuf (ref);struct firmware_cache *fwc = buf->fwc;
Signature · 1 line
1.8.1.4
Re: [PATCH 2/3] firmware loader: Add sparse annotation
Quoted 6 lines · Bart Van Assche
Avoid that sparse reports the following warning on
__fw_free_buf():
drivers/base/firmware_class.c:230:9: warning: context imbalance in '__fw_free_buf' - unexpected unlockSigned-off-by Bart Van Assche <[email protected]>Cc Ming Lei <[email protected]>
Bart, thanks.
Thanks,
--
Ming Lei
PATCH 3/3 driver-core: Fix use-after-free triggered by bus_unregister()
In reply to Bart Van AsscheAvoid that bus_unregister() triggers a use-after-free with CONFIG_DEBUG_KOBJECT_RELEASE=y. This patch avoids that the following sequence triggers a kernel crash with memory poisoning enabled:
* bus_register()
* driver_register()
* driver_unregister()
* bus_unregister()
The above sequence causes the bus private data to be freed from inside the bus_unregister() call although it is not guaranteed in that function that the reference count on the bus private data has dropped to zero. As an example, with CONFIG_DEBUG_KOBJECT_RELEASE=y the ${bus}/drivers kobject is still holding a reference on bus->p->subsys.kobj via its parent pointer at the time the bus private data is freed. Fix this by deferring freeing the bus private data until the last kobject_put() call on bus->p->subsys.kobj.
The kernel oops triggered by the above sequence and with memory poisoning enabled and that is fixed by this patch is as follows:
general protection fault: 0000 [#1] PREEMPT SMP CPU: 3 PID: 2711 Comm: kworker/3:32 Tainted: G W O 3.13.0-rc4-debug+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: events kobject_delayed_cleanup task: ffff880037f866d0 ti: ffff88003b638000 task.ti: ffff88003b638000 Call Trace: [<ffffffff81263105>] ? kobject_get_path+0x25/0x100 [<ffffffff81264354>] kobject_uevent_env+0x134/0x600 [<ffffffff8126482b>] kobject_uevent+0xb/0x10 [<ffffffff81262fa2>] kobject_delayed_cleanup+0xc2/0x1b0 [<ffffffff8106c047>] process_one_work+0x217/0x700 [<ffffffff8106bfdb>] ? process_one_work+0x1ab/0x700 [<ffffffff8106c64b>] worker_thread+0x11b/0x3a0 [<ffffffff8106c530>] ? process_one_work+0x700/0x700 [<ffffffff81074b70>] kthread+0xf0/0x110 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 [<ffffffff815673bc>] ret_from_fork+0x7c/0xb0 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 Code: 89 f8 48 89 e5 f6 82 c0 27 63 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 c0 27 63 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80 RIP [<ffffffff81267ed0>] strlen+0x0/0x30 RSP <ffff88003b639c70> ---[ end trace 210f883ef80376aa ]---
--- drivers/base/bus.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
drivers/base/bus.c +11 -2
@@ -146,8 +146,19 @@ void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) }EXPORT_SYMBOL_GPL (bus_remove_file); +static void bus_release (struct kobject *kobj) +{ +struct subsys_private *priv = +container_of (kobj,typeof (*priv), subsys.kobj); +struct bus_type *bus = priv->bus; + +kfree (priv); + bus->p =NULL ; +} +static struct kobj_type bus_ktype = { .sysfs_ops = &bus_sysfs_ops, + .release = bus_release, };static int bus_uevent_filter (struct kset *kset,struct kobject *kobj)
@@ -953,8 +964,6 @@ void bus_unregister(struct bus_type *bus)kset_unregister (bus->p->devices_kset);bus_remove_file (bus, &bus_attr_uevent);kset_unregister (&bus->p->subsys); -kfree (bus->p); - bus->p =NULL ; }EXPORT_SYMBOL_GPL (bus_unregister);
Signature · 1 line
1.8.1.4
Re: [PATCH 3/3] driver-core: Fix use-after-free triggered by bus_unregister()
Quoted 74 lines · Bart Van Assche
Avoid that
bus_unregister()triggers a use-after-free withCONFIG_DEBUG_KOBJECT_RELEASE=y. This patch avoids that the following sequence triggers a kernel crash with memory poisoning enabled:
*bus_register()
*driver_register()
*driver_unregister()
*bus_unregister()The above sequence causes the bus private data to be freed from inside the
bus_unregister()call although it is not guaranteed in that function that the reference count on the bus private data has dropped to zero. As an example, withCONFIG_DEBUG_KOBJECT_RELEASE=ythe ${bus}/drivers kobject is still holding a reference onbus->p->subsys.kobjvia its parent pointer at the time the bus private data is freed. Fix this by deferring freeing the bus private data until the lastkobject_put()call onbus->p->subsys.kobj.The kernel oops triggered by the above sequence and with memory poisoning enabled and that is fixed by this patch is as follows:
general protection fault: 0000 [#1] PREEMPT SMP CPU: 3 PID: 2711 Comm: kworker/3:32 Tainted: G W O 3.13.0-rc4-debug+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: events kobject_delayed_cleanup task: ffff880037f866d0 ti: ffff88003b638000 task.ti: ffff88003b638000 Call Trace: [<ffffffff81263105>] ? kobject_get_path+0x25/0x100 [<ffffffff81264354>] kobject_uevent_env+0x134/0x600 [<ffffffff8126482b>] kobject_uevent+0xb/0x10 [<ffffffff81262fa2>] kobject_delayed_cleanup+0xc2/0x1b0 [<ffffffff8106c047>] process_one_work+0x217/0x700 [<ffffffff8106bfdb>] ? process_one_work+0x1ab/0x700 [<ffffffff8106c64b>] worker_thread+0x11b/0x3a0 [<ffffffff8106c530>] ? process_one_work+0x700/0x700 [<ffffffff81074b70>] kthread+0xf0/0x110 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 [<ffffffff815673bc>] ret_from_fork+0x7c/0xb0 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 Code: 89 f8 48 89 e5 f6 82 c0 27 63 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 c0 27 63 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80 RIP [<ffffffff81267ed0>] strlen+0x0/0x30 RSP <ffff88003b639c70> ---[ end trace 210f883ef80376aa ]---Signed-off-by Bart Van Assche <[email protected]>--- drivers/base/bus.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)drivers/base/bus.c +11
-0@@ -146,8 +146,19 @@ void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) }EXPORT_SYMBOL_GPL (bus_remove_file); +static void bus_release (struct kobject *kobj) +{ +struct subsys_private *priv = +container_of (kobj,typeof (*priv), subsys.kobj); +struct bus_type *bus = priv->bus; + +kfree (priv); + bus->p =NULL ; +} +static struct kobj_type bus_ktype = { .sysfs_ops = &bus_sysfs_ops, + .release = bus_release, };static int bus_uevent_filter (struct kset *kset,struct kobject *kobj)
drivers/base/bus.c void bus_unregister(struct bus_type *bus) · line 968
Quoted 7 lines
drivers/base/bus.c +0
-2@@ -953,8 +964,6 @@ void bus_unregister(struct bus_type *bus)kset_unregister (bus->p->devices_kset);bus_remove_file (bus, &bus_attr_uevent);kset_unregister (&bus->p->subsys); -kfree (bus->p); - bus->p =NULL ; }EXPORT_SYMBOL_GPL (bus_unregister);
Looks the fix is fine,
Thanks,
--
Ming Lei