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Anand Jain
b5ddcffa37
The following test case leads to NULL kobject free error:
mount seed /mnt
add sprout to /mnt
umount /mnt
mount sprout to /mnt
delete seed
kobject: '(null)' (00000000dd2b87e4): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 1 PID: 15784 at lib/kobject.c:736 kobject_put+0x80/0x350
RIP: 0010:kobject_put+0x80/0x350
::
Call Trace:
btrfs_sysfs_remove_devices_dir+0x6e/0x160 [btrfs]
btrfs_rm_device.cold+0xa8/0x298 [btrfs]
btrfs_ioctl+0x206c/0x22a0 [btrfs]
ksys_ioctl+0xe2/0x140
__x64_sys_ioctl+0x1e/0x29
do_syscall_64+0x96/0x150
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4047c6288b
::
This is because, at the end of the seed device-delete, we try to remove
the seed's devid sysfs entry. But for the seed devices under the sprout
fs, we don't initialize the devid kobject yet. So add a kobject state
check, which takes care of the bug.
Fixes: 668e48af7a ("btrfs: sysfs, add devid/dev_state kobject and device attributes")
CC: stable@vger.kernel.org # 5.6+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.