Messages in this thread | | | Date | Tue, 19 Apr 2022 19:02:24 +0800 | Subject | Re: [PATCH] misc: ocxl: fix possible double free in ocxl_file_register_afu | From | Hangyu Hua <> |
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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);
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