On 11/4/19 2:56 AM, Jens Axboe wrote: > On 11/3/19 4:57 PM, Ming Lei wrote: >> On Sun, Nov 3, 2019 at 8:28 AM Chaitanya Kulkarni >> <Chaitanya.Kulkarni@xxxxxxx> wrote: >>> >>> Ming, >>> >>> On 11/02/2019 01:02 AM, Ming Lei wrote: >>>> It is reported that sysfs buffer overflow can be triggered in case >>>> of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs of >>>> hctx via/sys/block/$DEV/mq/$N/cpu_list. >>>> >>>> So use snprintf for avoiding the potential buffer overflow. >>>> >>>> This version doesn't change the attribute format, and simply stop >>>> to show CPU number if the buffer is to be overflow. >>> >>> Does it make sense to also add a print or WARN_ON in case of overflow ? >> >> Yes, it does, could you cook a patch for that? > > No it doesn't. The WARN_ON brings absolutely nothing. If you're using > a script, it gets the same values out and doesn't see the warning. If > it's a human cat'ing it, they will probably already realize that > we're missing CPUs. Or maybe not even see the warning. It's useless. > > We should either make this seqfile, or just kill the file. Those are > the only two options that make any sense. > I'd rather retain that file; it proved really useful when debugging interrupt affinity issues. Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 247165 (AG München), GF: Felix Imendörffer
