lkml.org 
[lkml]   [2022]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH] misc: ocxl: fix possible double free in ocxl_file_register_afu
    From
    On 2022/4/19 17:09, Frederic Barrat wrote:
    >
    >
    > On 18/04/2022 10:57, Hangyu Hua wrote:
    >> info_release() will be called in device_unregister() when info->dev's
    >> reference count is 0. So there is no need to call ocxl_afu_put() and
    >> kfree() again.
    >>
    >> Fix this by adding free_minor() and return to err_unregister error path.
    >>
    >> Fixes: 75ca758adbaf ("ocxl: Create a clear delineation between ocxl
    >> backend & frontend")
    >> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
    >> ---
    >
    >
    > Thanks for fixing that error path!
    > I'm now thinking it would be cleaner to have the call to free_minor() in
    > the info_release() callback but that would be another patch.
    > In any case:
    > Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
    >
    >   Fred
    >

    I think it is a good idea to use callbacks to handle all garbage
    collections. And free_minor is used only in ocxl_file_register_afu()
    andocxl_file_unregister_afu(). So this should only require minor changes.

    Thanks.

    >
    >>   drivers/misc/ocxl/file.c | 2 ++
    >>   1 file changed, 2 insertions(+)
    >>
    >> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
    >> index d881f5e40ad9..6777c419a8da 100644
    >> --- a/drivers/misc/ocxl/file.c
    >> +++ b/drivers/misc/ocxl/file.c
    >> @@ -556,7 +556,9 @@ int ocxl_file_register_afu(struct ocxl_afu *afu)
    >>   err_unregister:
    >>       ocxl_sysfs_unregister_afu(info); // safe to call even if
    >> register failed
    >> +    free_minor(info);
    >>       device_unregister(&info->dev);
    >> +    return rc;
    >>   err_put:
    >>       ocxl_afu_put(afu);
    >>       free_minor(info);

    \
     
     \ /
      Last update: 2022-04-19 13:04    [W:3.266 / U:0.468 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site