Commit c7fd62bc69 ("stm class: Introduce framing protocol drivers")
adds a bug into the error path of policy creation, that would do a
module_put() on a wrong module, if one tried to create a policy for
an stm device which already has a policy, using a different protocol.
IOW,
| mkdir /config/stp-policy/dummy_stm.0:p_basic.test
| mkdir /config/stp-policy/dummy_stm.0:p_sys-t.test # puts "p_basic"
| mkdir /config/stp-policy/dummy_stm.0:p_sys-t.test # "p_basic" -> -1
throws:
| general protection fault: 0000 [#1] SMP PTI
| CPU: 3 PID: 2887 Comm: mkdir
| RIP: 0010:module_put.part.31+0xe/0x90
| Call Trace:
| module_put+0x13/0x20
| stm_put_protocol+0x11/0x20 [stm_core]
| stp_policy_make+0xf1/0x210 [stm_core]
| ? __kmalloc+0x183/0x220
| ? configfs_mkdir+0x10d/0x4c0
| configfs_mkdir+0x169/0x4c0
| vfs_mkdir+0x108/0x1c0
| do_mkdirat+0xe8/0x110
| __x64_sys_mkdir+0x1b/0x20
| do_syscall_64+0x5a/0x140
| entry_SYSCALL_64_after_hwframe+0x44/0xa9
Correct this sad mistake by calling calling 'put' on the correct
reference, which happens to match another error path in the same
function, so we consolidate the two at the same time.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: c7fd62bc69 ("stm class: Introduce framing protocol drivers")
Reported-by: Ammy Yi <ammy.yi@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.
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