Messages in this thread | | | Date | Wed, 17 Aug 2022 14:43:29 +0200 | From | Greg KH <> | Subject | Re: [PATCH v7 1/2] devcoredump: remove the useless gfp_t parameter in dev_coredumpv and dev_coredumpm |
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On Wed, Aug 17, 2022 at 08:39:12PM +0800, Duoming Zhou wrote: > The dev_coredumpv() and dev_coredumpm() could not be used in atomic > context, because they call kvasprintf_const() and kstrdup() with > GFP_KERNEL parameter. The process is shown below: > > dev_coredumpv(.., gfp_t gfp) > dev_coredumpm(.., gfp_t gfp) > dev_set_name > kobject_set_name_vargs > kvasprintf_const(GFP_KERNEL, ...); //may sleep > kstrdup(s, GFP_KERNEL); //may sleep > > This patch removes gfp_t parameter of dev_coredumpv() and dev_coredumpm() > and changes the gfp_t parameter of kzalloc() in dev_coredumpm() to > GFP_KERNEL in order to show they could not be used in atomic context. > > Fixes: 833c95456a70 ("device coredump: add new device coredump class") > Reviewed-by: Brian Norris <briannorris@chromium.org> > Reviewed-by: Johannes Berg <johannes@sipsolutions.net> > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- > Changes in v7: > - Remove gfp_t flag in amdgpu device.
Again, this creates a "flag day" where we have to be sure we hit all users of this api at the exact same time. This will prevent any new driver that comes into a maintainer tree during the next 3 months from ever being able to use this api without cauing build breakages in the linux-next tree.
Please evolve this api to work properly for everyone at the same time, like was previously asked for so that we can take this change. It will take 2 releases, but that's fine.
thanks,
greg k-h
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