On Thu, 27 Oct 2022 13:50:08 -0700 Stephen Brennan <stephen.s.brennan@xxxxxxxxxx> wrote: > Though vmcoreinfo is intended to be small, at just one page, useful > information is still added to it, so we risk running out of space. > Currently there is no runtime check to see whether the vmcoreinfo buffer > has been exhausted. Add a warning for this case. > > Currently, my static checking tool[1] indicates that a good upper bound > for vmcoreinfo size is currently 3415 bytes, but the best time to add > warnings is before the risk becomes too high. > > ... > > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -383,6 +383,9 @@ void vmcoreinfo_append_str(const char *fmt, ...) > memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r); > > vmcoreinfo_size += r; > + > + WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES, > + "vmcoreinfo data exceeds allocated size, truncating"); > } Seems that vmcoreinfo_append_str() will truncate (ie: corrupt) the final entry when limiting the overall data size to VMCOREINFO_BYTES. And that final entry will be missing any terminating \n or \0. Is all this desirable, or should we be checking for (and warning about) sufficient space _before_ appending this string? _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
