Hi Mikhail, On Fri, Oct 10, 2025 at 10:55 PM Mikhail Zaslonko <[email protected]> wrote: > > Hello Tao, > > Have you reproduced the issue on s390? > Just trigger a segfault in the test program (e.g. by de-referencing a > null pointer), run crash on a live system and check the 'log' output. > Thanks for the suggestion. I will give null pointer dereferencing a try and post findings.
Thanks, Tao Liu > On 10/7/2025 1:36 PM, Mikhail Zaslonko wrote: > > Hi Tao, > > > > On 10/7/2025 1:11 AM, Tao Liu wrote: > >> On Tue, Sep 30, 2025 at 8:18 PM lijiang <[email protected]> wrote: > >>> > >>> On Tue, Sep 30, 2025 at 3:01 PM Mikhail Zaslonko <[email protected]> > >>> wrote: > >>>> > >>>> Hello, > >>>> > >>>> On 9/30/2025 4:53 AM, lijiang wrote: > >>>>> On Tue, Sep 30, 2025 at 2:18 AM Mikhail Zaslonko > >>>>> <[email protected]> > >>>>> wrote: > >>>>> > >>>>>> Hi Lianbo, > >>>>>> > >>>>>> It seems we have a problem printing disassembly blocks in the log after > >>>>>> this patch (at least on s390). > >>>>>> See number of empty lines printed below. > >>>>>> > >>>>> > >>>>> Can you try it with the following two patches? > >>>>> [1] > >>>>> https://www.mail-archive.com/[email protected]/msg01621.html > >>>> This patch is present on crash master, doesnt affect the issue. > >>>>> [2] > >>>>> https://www.mail-archive.com/[email protected]/msg01636.html > >>>>> > >>>> This one helps indeed! At least I do not se the blanks lines in my > >>>> scenario. > >>>> BUT, if I use 'log -R' the blank lines are back again! > >>> > >>> > >>> Thanks for the information, Mikhail. > >>> Let me see how to debug this(although I can not reproduce it on s390x). > >> > >> I didn't reproduce the issue on my s390x machine either, maybe sharing > >> the vmcore to us can help. > > > > I'm not sure I'm allowed to send this data outside. > > > > I think the problem takes place for the logs printed with pr_cont() by the > > kernel (e.g. show_code() of arch/s390/kernel/dis.c for printing disassembly > > as > > in my sample). > > > >> > >> Thanks, > >> Tao Liu > >> > >>> > >>> Thanks > >>> Lianbo > >>> > >>>> > >>>> > >>>>> > >>>>>> Before the patch: > >>>>>> [ 21.408784] Krnl GPRS: 000002aa3780c000 0000000000238c00 > >>>>>> 0000000015800000 0000000000001000 > >>>>>> [ 21.408787] 0000000008e30000 00000000b0001000 > >>>>>> 0000000000000000 0000000000000a55 > >>>>>> [ 21.408790] 0000000004c52300 000002aa3780c000 > >>>>>> 00000000084281d0 0000038000bfbd28 > >>>>>> [ 21.408794] 00000000075e9500 0000000004c52300 > >>>>>> 0000038000bfbbf0 0000038000bfbb90 > >>>>>> [ 21.408860] Krnl Code: 000000000e0acf48: c05fb0001000 llilf > >>>>>> %r5,2952794112 > >>>>>> 000000000e0acf4e: ec4100b30659 > >>>>>> risbgn > >>>>>> %r4,%r1,0,179,6 > >>>>>> #000000000e0acf54: 0e24 mvcl > >>>>>> %r2,%r4 > >>>>>> >000000000e0acf56: a7280000 lhi > >>>>>> %r2,0 > >>>>>> 000000000e0acf5a: eb6ff0a80004 lmg > >>>>>> %r6,%r15,168(%r15) > >>>>>> 000000000e0acf60: b9140022 lgfr > >>>>>> %r2,%r2 > >>>>>> 000000000e0acf64: 07fe bcr > >>>>>> 15,%r14 > >>>>>> 000000000e0acf66: 47000700 bc > >>>>>> 0,1792 > >>>>>> [ 21.408883] Call Trace: > >>>>>> > >>>>>> After the patch: > >>>>>> [ 21.408784] Krnl GPRS: 000002aa3780c000 0000000000238c00 > >>>>>> 0000000015800000 0000000000001000 > >>>>>> [ 21.408787] 0000000008e30000 00000000b0001000 > >>>>>> 0000000000000000 0000000000000a55 > >>>>>> [ 21.408790] 0000000004c52300 000002aa3780c000 > >>>>>> 00000000084281d0 0000038000bfbd28 > >>>>>> [ 21.408794] 00000000075e9500 0000000004c52300 > >>>>>> 0000038000bfbbf0 0000038000bfbb90 > >>>>>> [ 21.408860] > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> Krnl Code: 000000000e0acf48: c05fb0001000 llilf > >>>>>> %r5,2952794112 > >>>>>> [ 21.408883] Call Trace: > >>>>>> > >>>>>> I think your approach of storing printable characters in the buffer > >>>>>> with > >>>>>> the intention to modify it > >>>>>> afterwards (see [1] below) instead of writing it character wise does > >>>>>> not > >>>>>> work when the input data > >>>>>> contains several lines. Those '\n' are written one by one, what leads > >>>>>> to > >>>>>> the result shown above. > >>>>>> You should probably buffer and 'demangle' each line separately. > >>>>>> > >>>>> > >>>>> Looks like different issues. Can you share your vmcore and vmlinux with > >>>>> me? I did not reproduce it. > >>>> > >>>> > >>>>> > >>>>> Thanks > >>>>> Lianbo > >>>>> > >>>>>> > >>>>>> > >>>>> > >>>> > >> > > > -- 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
