diff options
author | Viresh Kumar <viresh.kumar@linaro.org> | 2016-05-14 23:42:23 +0530 |
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committer | Greg Kroah-Hartman <gregkh@google.com> | 2016-05-15 00:23:52 +0200 |
commit | 96ba6740099b1f1a2732c86204d2931cda11d638 (patch) | |
tree | ae84fd820a80b88593c07c072fc457ce9b627fdf /drivers/staging/greybus/fw-core.c | |
parent | 04f0e6ebd1a2ca3a1f1a356e9a07ef1797ef1b7c (diff) |
greybus: fw-management: Free fw-mgmt only after all users are gone
The fw-management driver rightly destroys the char device on
connection-exit, but that doesn't guarantee that all of the users of the
device are gone.
Userspace may still be holding file-descriptor of the char device and
can initiate new ioctl operations. And that *will* lead to kernel crash.
To avoid this issue, manage struct users with kref, manage a list of
'struct fw-mgmt' and start using the structure only after getting its
kref incremented.
The important part is the routine get_fw_mgmt(), which increments the
reference to the struct before returning it to the caller. The list of
fw-mgmt structs in protected with a mutex to avoid any races around
that.
The kref is incremented once the char device is opened and dropped only
when it is closed.
Reported-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Diffstat (limited to 'drivers/staging/greybus/fw-core.c')
0 files changed, 0 insertions, 0 deletions