Messages in this thread |  | | Subject | Re: [Regression] Missing device nodes for ETR, ETF and STM after CONFIG_UEVENT_HELPER=n | From | Sai Prakash Ranjan <> | Date | Fri, 26 Jul 2019 13:50:27 +0530 |
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On 7/26/2019 12:34 PM, Greg Kroah-Hartman wrote: > On Fri, Jul 26, 2019 at 11:49:19AM +0530, Sai Prakash Ranjan wrote: >> Hi, >> >> When trying to test my coresight patches, I found that etr,etf and stm >> device nodes are missing from /dev. > > I have no idea what those device nodes are. > >> Bisection gives this as the bad commit. >> >> 1be01d4a57142ded23bdb9e0c8d9369e693b26cc is the first bad commit >> commit 1be01d4a57142ded23bdb9e0c8d9369e693b26cc >> Author: Geert Uytterhoeven <geert+renesas@glider.be> >> Date: Thu Mar 14 12:13:50 2019 +0100 >> >> driver: base: Disable CONFIG_UEVENT_HELPER by default >> >> Since commit 7934779a69f1184f ("Driver-Core: disable /sbin/hotplug by >> default"), the help text for the /sbin/hotplug fork-bomb says >> "This should not be used today [...] creates a high system load, or >> [...] out-of-memory situations during bootup". The rationale for this >> was that no recent mainstream system used this anymore (in 2010!). >> >> A few years later, the complete uevent helper support was made optional >> in commit 86d56134f1b67d0c ("kobject: Make support for uevent_helper >> optional."). However, if was still left enabled by default, to support >> ancient userland. >> >> Time passed by, and nothing should use this anymore, so it can be >> disabled by default. >> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> >> drivers/base/Kconfig | 1 - >> 1 file changed, 1 deletion(-) >> >> >> Any idea on this? > > That means that who ever created those device nodes is relying on udev > to do this, and is not doing the correct thing within the kernel and > using devtmpfs. > > Any pointers to where in the kernel those devices are trying to be > created? >
Somewhere in drivers/hwtracing/coresight/* probably. I am not sure, Mathieu/Suzuki would be able to point you to the exact code.
Also just to add on some more details, I am using *initramfs*
Thanks, Sai
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