On Wed 2022-11-09 10:33:55, John Ogness wrote: > Hi Daniel, > > On 2022-11-09, Daniel Thompson <daniel.thomp...@linaro.org> wrote: > >> + /* > >> + * The console_srcu_read_lock() only provides safe console list > >> + * traversal. The use of the ->write() callback relies on all other > >> + * CPUs being stopped at the moment and console drivers being able to > >> + * handle reentrance when @oops_in_progress is set. (Note that there > >> + * is no guarantee for either criteria.) > >> + */ > > > > The debugger entry protocol does ensure that other CPUs are either > > stopped or unresponsive. In the case where the other CPU is unresponsive > > (e.g. timed out after being asked to stop) then there is a "real" printk() > > issued prior to any of the above interference with the console system to > > the developer driving the debugger gets as much clue as we can offer them > > about what is going on (typically this is emitted from regular interrupt > > context). > > > > Given this comment is part of the debugger code then for the > > oops_in_progress hack it might be more helpful to describe what > > the developer in front the debugger needs to do to have the most > > reliable debug session possible. > > > > There is no guarantee that every console drivers can handle reentrance > > in this way; the developer deploying the debugger is responsible for > > ensuring that the console drivers they have selected handle reentrance > > appropriately. > > Thanks for the explanation. I will change the comment to: > > /* > * The console_srcu_read_lock() only provides safe console list > * traversal. The use of the ->write() callback relies on all other > * CPUs being stopped at the moment and console drivers being able to > * handle reentrance when @oops_in_progress is set. > * > * There is no guarantee that every console driver can handle > * reentrance in this way; the developer deploying the debugger > * is responsible for ensuring that the console drivers they > * have selected handle reentrance appropriately. > */
Looks good to me. After merging this with the 10th patch that adds the data_race() annotated check of CON_ENABLED flag: Reviewed-by: Petr Mladek <pmla...@suse.com> Best Regards, Petr _______________________________________________ Kgdb-bugreport mailing list Kgdb-bugreport@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
