On Tue, May 28, 2019 at 11:39:22AM +0000, Kalle Valo wrote: > Gen Zhang <blackgod016574@xxxxxxxxx> wrote: > > > In wl1271_probe(), 'glue->core' is allocated by platform_device_alloc(), > > when this allocation fails, ENOMEM is returned. However, 'pdev_data' > > and 'glue' are allocated by devm_kzalloc() before 'glue->core'. When > > platform_device_alloc() returns NULL, we should also free 'pdev_data' > > and 'glue' before wl1271_probe() ends to prevent leaking memory. > > > > Similarly, we shoulf free 'pdev_data' when 'glue' is NULL. And we should > > free 'pdev_data' and 'glue' when 'glue->reg' is error and when 'ret' is > > error. > > > > Further, we should free 'glue->core', 'pdev_data' and 'glue' when this > > function normally ends to prevent leaking memory. > > > > Signed-off-by: Gen Zhang <blackgod016574@xxxxxxxxx> > > Same questions as with similar SDIO patch: > > https://patchwork.kernel.org/patch/10959049/ > > Patch set to Changes Requested. > > -- > https://patchwork.kernel.org/patch/10959053/ > > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches > Thanks for your reply, Kalle. I had debate with Jon about this patch. You could kindly refer to lkml: https://lkml.org/lkml/2019/5/23/1547. And I don't think a practical conclusion is made there. Further, I e-mailed Greg K-H about when should we use devm_kmalloc(). On Tue, May 28, 2019 at 08:32:57AM +0800, Gen Zhang wrote: > devm_kmalloc() is used to allocate memory for a driver dev. Comments > above the definition and doc > (https://www.kernel.org/doc/Documentation/driver-model/devres.txt) all > imply that allocated the memory is automatically freed on driver attach, > no matter allocation fail or not. However, I examined the code, and > there are many sites that devm_kfree() is used to free devm_kmalloc(). > e.g. hisi_sas_debugfs_init() in drivers/scsi/hisi_sas/hisi_sas_main.c. > So I am totally confused about this issue. Can anybody give me some > guidance? When should we use devm_kfree()? He replied: If you "know" you need to free the memory now, call devm_kfree(). If you want to wait for it to be cleaned up latter, like normal, then do not call it. So could please look in to this issue? Thanks Gen
