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Athira Rajeev
e59fea47f8
perf symbols: Fix DSO kernel load and symbol process to correctly map DSO to its long_name, type and adjust_symbols
Test "object code reading" fails sometimes for kernel address as below: Reading object code for memory address: 0xc000000000004c3c File is: [kernel.kallsyms] On file address is: 0x14c3c dso__data_read_offset failed test child finished with -1 ---- end ---- Object code reading: FAILED! Here dso__data_read_offset() fails for symbol address 0xc000000000004c3c. This is because the DSO long_name here is "[kernel.kallsyms]" and hence open_dso() fails to open this file. There is an incorrect DSO to map handling here. The key points here are: - The DSO long_name is set to "[kernel.kallsyms]". This file is not present and hence returns error - The DSO binary type is set to DSO_BINARY_TYPE__NOT_FOUND - The DSO adjust_symbols member is set to zero In the end dso__data_read_offset() returns -1 and the address 0x14c3c can not be resolved. Hence the test fails. But the address actually maps to the kernel DSO # objdump -z -d --start-address=0xc000000000004c3c --stop-address=0xc000000000004cbc /home/athira/linux/vmlinux /home/athira/linux/vmlinux: file format elf64-powerpcle Disassembly of section .head.text: c000000000004c3c <exc_virt_0x4c00_system_call+0x3c>: c000000000004c3c: a6 02 9b 7d mfsrr1 r12 c000000000004c40: 78 13 42 7c mr r2,r2 c000000000004c44: 18 00 4d e9 ld r10,24(r13) c000000000004c48: 60 c6 4a 61 ori r10,r10,50784 c000000000004c4c: a6 03 49 7d mtctr r10 Fix dso__process_kernel_symbol() to set the binary_type and adjust_symbols members. dso->adjust_symbols is used by map__rip_2objdump() which converts the symbol start address to the objdump address. Also set dso->long_name in dso__load_vmlinux(). Suggested-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Disha Goel <disgoel@linux.vnet.ibm.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20230811051546.70039-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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