On 6/18/20 10:53 AM, Conrad Meyer wrote: > On Thu, Jun 18, 2020 at 10:19 AM John Baldwin <j...@freebsd.org> wrote: >> >> On 6/17/20 5:48 PM, Conrad Meyer wrote: >>> db_printf checks the pager, via db_putc. >> >> It doesn't break out of the loops for you though (e.g. via setjmp or the >> like). Commands still have to check db_pager_quit directly if they wish >> to abort early to honor a user entering 'q' at the pager prompt. > > It does for Ctrl-C, but not 'q', true. It could easily do the same > for 'q' as Ctrl-C: db_error(NULL) => kdb_reenter_silent().
That's only safe if commands are always idempotent. Some commands can use try locks (though they really shouldn't). Having printf() auto-convert is potentially worse for this as it affects doing a 'call' of an arbitrary function (which is likely not written to be safe for DDB). Though that's already a bit fraught with dragons since any nested panic already does the longjmp. We skip locking (though only somewhat, you can "unlock" a lock held by the interrupted code in your thread by calling a function). It may be that having 'q' longjmp is ok and wouldn't really be more fragile than what is already there. That is still orthogonal to your patch (which is printf -> db_printf in effect) (and so 2 separate things to consider). -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
