Hi, On Fri, Dec 7, 2018 at 9:42 AM Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > On Tue, Dec 04, 2018 at 07:38:24PM -0800, Douglas Anderson wrote: > > Douglas Anderson (4): > > kgdb: Remove irq flags from roundup > > kgdb: Fix kgdb_roundup_cpus() for arches who used smp_call_function() > > kgdb: Don't round up a CPU that failed rounding up before > > kdb: Don't back trace on a cpu that didn't round up > > FWIW, trying these on arm64 (ThunderX2) with CONFIG_KGDB_TESTS_ON_BOOT=y > on top of 4.20-rc5 doesn't boot. It looks like they leave interrupts > disabled when they shouldn't and it trips over the BUG at > mm/vmalloc.c:1380 (called via do_fork -> copy_process). > > Now, I don't think these patches make things worse on arm64 since prior > to them the kgdb boot tests on arm64 were stuck in a loop (RUN > singlestep). Thanks for the report! ...actually, I'd never tried CONFIG_KGDB_TESTS before. ...so I tried them now: A) chromeos-4.19 tree on qcom-sdm845 without this series: booted up OK B) chromeos-4.19 tree on qcom-sdm845 with this series: booted up OK C) v4.20-rc5-90-g30002dd008ed on rockchip-rk3399 (kevin) with this series: booted up OK Example output from B) above: localhost ~ # dmesg | grep kgdbts [ 2.139814] KGDB: Registered I/O driver kgdbts [ 2.144582] kgdbts:RUN plant and detach test [ 2.165333] kgdbts:RUN sw breakpoint test [ 2.172990] kgdbts:RUN bad memory access test [ 2.178640] kgdbts:RUN singlestep test 1000 iterations [ 2.187765] kgdbts:RUN singlestep [0/1000] [ 2.559596] kgdbts:RUN singlestep [100/1000] [ 2.931419] kgdbts:RUN singlestep [200/1000] [ 3.303474] kgdbts:RUN singlestep [300/1000] [ 3.675121] kgdbts:RUN singlestep [400/1000] [ 4.046867] kgdbts:RUN singlestep [500/1000] [ 4.418920] kgdbts:RUN singlestep [600/1000] [ 4.790824] kgdbts:RUN singlestep [700/1000] [ 5.162479] kgdbts:RUN singlestep [800/1000] [ 5.534103] kgdbts:RUN singlestep [900/1000] [ 5.902299] kgdbts:RUN do_fork for 100 breakpoints [ 8.463900] KGDB: Unregistered I/O driver kgdbts, debugger disabled ...so I guess I'm a little confused. Either I have a different config than you do or something is special about your machine? NOTE: In general I've never considered "single step" as reliable in kgdb. I mostly use kgdb as "after the fact" crash debugging to analyze local variables / memory / other tasks. If it worked that'd actually be kinda great, but at least when I started using kgdb years ago I learned that it didn't work and stopped trying... -Doug _______________________________________________ linux-snps-arc mailing list linux-snps-arc@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-snps-arc
