Hi Aditya, Sure, thanks for your help. The vmcore is a little bit large, please give me some time to process it.
Thanks, Tao Liu On Thu, Nov 20, 2025 at 5:36 PM Aditya Gupta <[email protected]> wrote: > > > On 19/11/25 09:41, Tao Liu wrote: > > Sorry I forgot to cc Aditya. Adding Aditya in the thread. > > > > On Wed, Nov 19, 2025 at 5:09 PM Tao Liu <[email protected]> wrote: > >> This patch will cause a regression on some x86_64 vmcores. > >> > >> $ crash -s vmcore vmlinux.gz > >> WARNING: vmcoreinfo is empty, will read from symbols > >> crash: cannot malloc vmcoreinfo buffer > >> crash: /var/tmp/vmlinux.gz_fWV3kA and vmcore do not match! > >> > >> The root cause is, in main.c, is_kdump() calls is_netdump(), which will > >> set pc->read_vmcoreinfo as vmcoreinfo_read_from_memory(), rather than > >> original vmcoreinfo_read_string(). > >> > >> Later in machdep_init(PRE_SYMTAB), vmcoreinfo_read_from_memory() doesn't > >> get "relocate" string, so fails for set kaslr flag, then fails for > >> linux_banner detection: > >> > >> Thread 1 "crash" hit Breakpoint 2, verify_version (): > >> 1096 if (!IS_KVADDR(linux_banner)) > >> (gdb) p/x linux_banner > >> $4 = 0xffffffff81e00100 > >> > >> crash> sym linux_banner > >> ffffffff9aa00100 (R) linux_banner > >> > >> As we can see with the patch applied, linux_banner got a wrong address. > >> So this patch currently is unsafe, and should be reverted before the fix. > >> > >> Signed-off-by: Tao Liu <[email protected]> > >> --- > >> > >> Since it is too close to the new release date of crash utility, I don't > >> have enough time for full root cause analysis and re-testing. So currently > >> the best option is to revert it for now, and fix it in the next release > >> then > >> re-apply. > > Hello Tao, > > Can you share the vmcore and vmlinux somewhere ? > > Is this with some special configuration, like something related kaslr > you mentioned ? > > Thanks for the initial analysis, I will try to debug this. > > Interestingly I did not hit this issue in my testing, but yes revert > makes sense since it has broken crash-utility. > > > Thanks, > > - Aditya G > > -- Crash-utility mailing list -- [email protected] To unsubscribe send an email to [email protected] https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki
