mainlining shenanigans
1deec1bd96
When perf processes build-id event, it creates DSOs with the build-id. But it didn't set the module short name (like '[module-name]') so when processing a kernel mmap event of the module, it cannot found the DSO as it only checks the short names. That leads for perf to create a same DSO without the build-id info and it'll lookup the system path even if the DSO is already in the build-id cache. After kernel was updated, perf cannot find the DSO and cannot show symbols in it anymore. You can see this if you have an old data file (w/ old kernel version): $ perf report -i perf.data.old -v |& grep scsi_mod build id event received for /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz : cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 Failed to open /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz, continuing without symbols ... The second message didn't show the build-id. With this patch: $ perf report -i perf.data.old -v |& grep scsi_mod build id event received for /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz: cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz with build id cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 not found, continuing without symbols ... Now it shows the build-id but still cannot load the symbol table. This is a different problem which will be fixed in the next patch. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/20170531120105.21731-1-namhyung@kernel.org [ Fix the build on older compilers (debian <= 8, fedora <= 21, etc) wrt kmod_path var init ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.