>From: Gregory Nutt <spudan...@gmail.com> >Sent: 03 March 2023 19:03 > >On 3/3/2023 12:56 PM, Gregory Nutt wrote: >> On 3/3/2023 12:36 PM, Nathan Hartman wrote: >>> On Fri, Mar 3, 2023 at 1:07 PM Tim Hardisty <t...@hardisty.co.uk> wrote: >>>> - I have enabled CONFIG_SIGKILL_ACTION to allow me to ctrl-c from >>>> the console if the app is misbehaving or, I thought, just to exit it. >>>> >>>> The behaviours I see are: >>>> >>>> 1) If I ctrl-c, the open files are not closed and if I re-run the >>>> app, the system crashes. It is the very first printf statement of >>>> the app that causes the crash, at the point the printf routine calls >>>> lib_fflush (not looked further yet). >> >> SIGINT, SIGKILL, etc. don't do graceful shutdowns like exit() does. >> They should behave as though _exit() were called which does an >> immediate termination. However, _exit() is still required to close >> all open file descriptor (Per Linux man page) and, if it does not, >> that would be a bug. >> >> SIGKILL can't be caught (again per the Linux man page) >> >> https://man7.org/linux/man-pages/man2/exit.2.html >> https://man7.org/linux/man-pages/man7/signal.7.html >> >"Closing" per se is probably not a the root of the problem when the file >descriptors are deallocated when the task group terminates, all of the >descriptors are freed. However, I suspect the there may be an open >reference count in the drivers which is not decrements and whcih could >subsequently in interfere with the correct behavior or a driver. > >
To divert from procedural discussion... I think I take it from the above that a CTRL-C is not a clean exit; but is not the root cause of the issue I'm seeing. The crash is at a printf the very first line of the app. And the same is true if I run another example app after a ctrl-c out of my new test app that uses printf. It is not to do with any interaction with file open/close/ioctl etc. as I first thought. I don't get why a ctrl-c out of an app causes printf to completely crash the board with no useful debug info to be had! The call stack simply shows it was due to an ARM data abort exception. I am quite sure I have made some "daft" Kconfig change (or not made a selection I should have done) - I welcome any suggestions before I shrug my shoulders and conclude this is just "one of those things" :)
