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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Adrian Hunter
bee4ceb8ea
[ Upstream commit70df07838f] Do not increase the node count unless a node has been successfully read, because it can lead to a segfault if an error occurs. For example, if perf exceeds the open file limit in memory_node__read(), which, on a test system, could be made to happen by setting the file limit to exactly 32: Before: $ ulimit -n 32 $ perf mem record --all-user -- sleep 1 [ perf record: Woken up 1 times to write data ] failed: can't open memory sysfs data perf: Segmentation fault Obtained 14 stack frames. perf(sighandler_dump_stack+0x48) [0x55f4b1f59558] /lib/x86_64-linux-gnu/libc.so.6(+0x42520) [0x7f4ba1c42520] /lib/x86_64-linux-gnu/libc.so.6(free+0x1e) [0x7f4ba1ca53fe] perf(+0x178ff4) [0x55f4b1f48ff4] perf(+0x179a70) [0x55f4b1f49a70] perf(+0x17ef5d) [0x55f4b1f4ef5d] perf(+0x85c0b) [0x55f4b1e55c0b] perf(cmd_record+0xe1d) [0x55f4b1e5920d] perf(cmd_mem+0xc96) [0x55f4b1e80e56] perf(+0x130460) [0x55f4b1f00460] perf(main+0x689) [0x55f4b1e427d9] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7f4ba1c29d90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f4ba1c29e40] perf(_start+0x25) [0x55f4b1e42a25] Segmentation fault (core dumped) $ After: $ ulimit -n 32 $ perf mem record --all-user -- sleep 1 [ perf record: Woken up 1 times to write data ] failed: can't open memory sysfs data [ perf record: Captured and wrote 0.005 MB perf.data (11 samples) ] $ Fixes:f8e502b9d1("perf header: Ensure bitmaps are freed") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Acked-by: Ian Rogers <irogers@google.com> Cc: German Gomez <german.gomez@arm.com> Cc: Ian Rogers <irogers@google.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20231123075848.9652-2-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.