[Crash-utility] Re: [PATCH] Disable DT_DEBUG lookup by GDB inside the vmcore

Hi Tao Thanks for your feedback. > Agreed, the same code exists in gdb-10.2 and hasn't reported the > warning message, so the root cause is somewhere else. I believe the change was introduced with this gdb patch [1] aebb370 ("gdb, solib-svr4: support namespaces in DSO iteration") where the call to elf_locate_base was added inside the function `svr4_iterate_over_objfiles_in_search_order`. which will be called alot of times during the crash initialization. [1] https://github.com/bminor/binutils-gdb/commit/aebb370bae3f511df8afb68a01a... > I'm not > confident that skipping the execution of the code might cause > regressions, because there are kernel modules, I think `elf_locate_base` part should be only for top level target. I have tested the module loading functionality with my patch applied, and it still successfully handles the `mod -S` command. Please let me know if there’s anything else i should try or verify. > which are also elf > files, which might need the inspection of the .dynamic section. At > least I didn't see any evidence from this patch to address it is safe > for the skipping... I wanted to verify whether the kernel ever includes DT_DEBUG information. To investigate this, I printed the data being read inside the crash::xfer_partial function (which is invoked via elf_locate_base to read from the vmcore). However, even when running crash with /proc/kcore, all the output data was zero. So, i believe that kernel will never have this `DT_DEBUG` information. > > Thanks, > Tao Liu Thanks ~Shivang.