Messages in this thread | | | Date | Fri, 25 Sep 2009 08:59:33 +0800 | From | Li Zefan <> | Subject | Re: [PATCH] Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs |
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>>> connection between kobj and sysfs. It's somewhat unclear why all the >>> kobject operation are only within this if(){} block - so I've thought >>> there is some reason... >>> IMHO only elv_unregister_queue() should be probably in the if(){} block. >>> >> Seems it's a bug to put kobject_put(dev->kobj) in the if block. >> >> I created a stacked device (mdadm) and kmemleak still reported leaks >> even after I fixed the blktrace issue. And then I moved kobejct_put() >> outside the if, no more leaks reports. >> > > Ok - I didn't have a testcase where the request_fn would be NULL.
Here you are ;)
mdadm --create --level=linear --raid-devices=1 --force /dev/md0 /dev/sda6
> So in this case I propose this patch: >
Looks good.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
> --- > Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs > introduced in commit 1d54ad6da9192fed5dd3b60224d9f2dfea0dcd82. > Release kobject also in case the request_fn is NULL. > > Problem was noticed via kmemleak backtrace when some sysfs entries were > note properly destroyed during device removal: > > unreferenced object 0xffff88001aa76640 (size 80): > comm "lvcreate", pid 2120, jiffies 4294885144 > hex dump (first 32 bytes): > 01 00 00 00 00 00 00 00 f0 65 a7 1a 00 88 ff ff .........e...... > 90 66 a7 1a 00 88 ff ff 86 1d 53 81 ff ff ff ff .f........S..... > backtrace: > [<ffffffff813f9cc6>] kmemleak_alloc+0x26/0x60 > [<ffffffff8111d693>] kmem_cache_alloc+0x133/0x1c0 > [<ffffffff81195891>] sysfs_new_dirent+0x41/0x120 > [<ffffffff81194b0c>] sysfs_add_file_mode+0x3c/0xb0 > [<ffffffff81197c81>] internal_create_group+0xc1/0x1a0 > [<ffffffff81197d93>] sysfs_create_group+0x13/0x20 > [<ffffffff810d8004>] blk_trace_init_sysfs+0x14/0x20 > [<ffffffff8123f45c>] blk_register_queue+0x3c/0xf0 > [<ffffffff812447e4>] add_disk+0x94/0x160 > [<ffffffffa00d8b08>] dm_create+0x598/0x6e0 [dm_mod] > [<ffffffffa00de951>] dev_create+0x51/0x350 [dm_mod] > [<ffffffffa00de823>] ctl_ioctl+0x1a3/0x240 [dm_mod] > [<ffffffffa00de8f2>] dm_compat_ctl_ioctl+0x12/0x20 [dm_mod] > [<ffffffff81177bfd>] compat_sys_ioctl+0xcd/0x4f0 > [<ffffffff81036ed8>] sysenter_dispatch+0x7/0x2c > [<ffffffffffffffff>] 0xffffffffffffffff > > Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com> > --- > block/blk-sysfs.c | 11 ++++++----- > include/linux/blktrace_api.h | 2 ++ > kernel/trace/blktrace.c | 5 +++++ > 3 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c > index b78c9c3..8a6d81a 100644 > --- a/block/blk-sysfs.c > +++ b/block/blk-sysfs.c > @@ -452,6 +452,7 @@ int blk_register_queue(struct gendisk *disk) > if (ret) { > kobject_uevent(&q->kobj, KOBJ_REMOVE); > kobject_del(&q->kobj); > + blk_trace_remove_sysfs(disk_to_dev(disk)); > return ret; > } > > @@ -465,11 +466,11 @@ void blk_unregister_queue(struct gendisk *disk) > if (WARN_ON(!q)) > return; > > - if (q->request_fn) { > + if (q->request_fn) > elv_unregister_queue(q); > > - kobject_uevent(&q->kobj, KOBJ_REMOVE); > - kobject_del(&q->kobj); > - kobject_put(&disk_to_dev(disk)->kobj); > - } > + kobject_uevent(&q->kobj, KOBJ_REMOVE); > + kobject_del(&q->kobj); > + blk_trace_remove_sysfs(disk_to_dev(disk)); > + kobject_put(&disk_to_dev(disk)->kobj); > } > diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h > index 7e4350e..622939a 100644 > --- a/include/linux/blktrace_api.h > +++ b/include/linux/blktrace_api.h > @@ -198,6 +198,7 @@ extern int blk_trace_setup(struct request_queue > *q, char *name, dev_t dev, > char __user *arg); > extern int blk_trace_startstop(struct request_queue *q, int start); > extern int blk_trace_remove(struct request_queue *q); > +extern void blk_trace_remove_sysfs(struct device *dev); > extern int blk_trace_init_sysfs(struct device *dev); > > extern struct attribute_group blk_trace_attr_group; > @@ -211,6 +212,7 @@ extern struct attribute_group blk_trace_attr_group; > # define blk_trace_startstop(q, start) (-ENOTTY) > # define blk_trace_remove(q) (-ENOTTY) > # define blk_add_trace_msg(q, fmt, ...) do { } while (0) > +# define blk_trace_remove_sysfs(struct device *dev) do { } while (0) > static inline int blk_trace_init_sysfs(struct device *dev) > { > return 0; > diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c > index 3eb159c..60b5c5a 100644 > --- a/kernel/trace/blktrace.c > +++ b/kernel/trace/blktrace.c > @@ -1657,6 +1657,11 @@ int blk_trace_init_sysfs(struct device *dev) > return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); > } > > +void blk_trace_remove_sysfs(struct device *dev) > +{ > + sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); > +} > + > #endif /* CONFIG_BLK_DEV_IO_TRACE */ > > #ifdef CONFIG_EVENT_TRACING
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