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Tiezhu Yang
0c5f1acc2a
When I execute 'perf top' without HAVE_LIBBPF_SUPPORT, there exists the following segmentation fault, skip the side-band event setup to fix it, this is similar with commit1101c872c8("perf record: Skip side-band event setup if HAVE_LIBBPF_SUPPORT is not set"). [yangtiezhu@linux perf]$ ./perf top <SNIP> perf: Segmentation fault Obtained 6 stack frames. ./perf(sighandler_dump_stack+0x5c) [0x12011b604] [0xffffffc010] ./perf(perf_mmap__read_init+0x3e) [0x1201feeae] ./perf() [0x1200d715c] /lib64/libpthread.so.0(+0xab9c) [0xffee10ab9c] /lib64/libc.so.6(+0x128f4c) [0xffedc08f4c] Segmentation fault [yangtiezhu@linux perf]$ I use git bisect to find commitb38d85ef49("perf bpf: Decouple creating the evlist from adding the SB event") is the first bad commit, so also add the Fixes tag. Committer testing: First build perf explicitely disabling libbpf: $ make NO_LIBBPF=1 O=/tmp/build/perf -C tools/perf install-bin && perf test python Now make sure it isn't linked: $ perf -vv | grep -w bpf bpf: [ OFF ] # HAVE_LIBBPF_SUPPORT $ $ nm ~/bin/perf | grep libbpf $ And now try to run 'perf top': # perf top perf: Segmentation fault -------- backtrace -------- perf[0x5bcd6d] /lib64/libc.so.6(+0x3ca6f)[0x7fd0f5a66a6f] perf(perf_mmap__read_init+0x1e)[0x5e1afe] perf[0x4cc468] /lib64/libpthread.so.0(+0x9431)[0x7fd0f645a431] /lib64/libc.so.6(clone+0x42)[0x7fd0f5b2b912] # Applying this patch fixes the issue. Fixes:b38d85ef49("perf bpf: Decouple creating the evlist from adding the SB event") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xuefeng Li <lixuefeng@loongson.cn> Link: http://lore.kernel.org/lkml/1597753837-16222-1-git-send-email-yangtiezhu@loongson.cn 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.