On Tue, Feb 18, 2025 at 12:00:11PM +0100, Théo Lebrun wrote: > The use-after-free bug appears when: > - A platform device is created from OF, by of_device_add(); > - The same device's name is changed afterwards using dev_set_name(), > by its probe for example. > > Out of the 37 drivers that deal with platform devices and do a > dev_set_name() call, only one might be affected. That driver is > loongson-i2s-plat [0]. All other dev_set_name() calls are on children > devices created on the spot. The issue was found on downstream kernels > and we don't have what it takes to test loongson-i2s-plat. > > Note: loongson-i2s-plat maintainers are CCed. > > ⟩ # Finding potential trouble-makers: > ⟩ git grep -l 'struct platform_device' | xargs grep -l dev_set_name > > The solution proposed is to add a flag to platform_device that tells if > it is responsible for freeing its name. We can then duplicate the > device name inside of_device_add() instead of copying the pointer. Ick. > What is done elsewhere? > - Platform bus code does a copy of the argument name that is stored > alongside the struct platform_device; see platform_device_alloc()[1]. > - Other busses duplicate the device name; either through a dynamic > allocation [2] or through an array embedded inside devices [3]. > - Some busses don't have a separate name; when they want a name they > take it from the device [4]. Really ick. Let's do the right thing here and just get rid of the name pointer entirely in struct platform_device please. Isn't that the correct thing that way the driver core logic will work properly for all of this. thanks, greg k-h
