linux/tools
Ryan Roberts 58e2847ad2 selftests: line buffer test program's stdout
Patch series "selftests/mm fixes for arm64", v3.

Given my on-going work on large anon folios and contpte mappings, I
decided it would be a good idea to start running mm selftests to help
guard against regressions.  However, it soon became clear that I
couldn't get the suite to run cleanly on arm64 with a vanilla v6.5-rc1
kernel (perhaps I'm just doing it wrong??), so got stuck in a rabbit
hole trying to debug and fix all the issues.  Some were down to
misconfigurations, but I also found a number of issues with the tests
and even a couple of issues with the kernel.


This patch (of 8):

The selftests runner pipes the test program's stdout to tap_prefix.  The
presence of the pipe means that the test program sets its stdout to be
fully buffered (as aposed to line buffered when directly connected to the
terminal).  The block buffering means that there is often content in the
buffer at fork() time, which causes the output to end up duplicated.  This
was causing problems for mm:cow where test results were duplicated 20-30x.

Solve this by using `stdbuf`, when available to force the test program to
use line buffered mode.  This means previously printf'ed results are
flushed out of the program before any fork().

Additionally, explicitly set line buffer mode in ksft_print_header(),
which means that all test programs that use the ksft framework will
benefit even if stdbuf is not present on the system.

[ryan.roberts@arm.com: add setvbuf() to set buffering mode]
  Link: https://lkml.kernel.org/r/20230726070655.2713530-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20230724082522.1202616-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20230724082522.1202616-2-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18 10:12:42 -07:00
..
accounting
arch tools headers arm64: Sync arm64's cputype.h with the kernel sources 2023-07-14 10:36:16 -03:00
bootconfig
bpf tools/resolve_btfids: Fix setting HOSTCFLAGS 2023-06-05 15:44:47 -07:00
build perf build: Fix broken feature check for libtracefs due to external lib changes 2023-07-11 13:17:05 -03:00
certs
cgroup
counter tools/counter: Makefile: Remove lingering 'include' directories on make clean 2023-05-09 19:17:17 -04:00
debugging
edid
firewire
firmware
gpio tools: gpio: fix debounce_period_us output of lsgpio 2023-05-11 10:56:24 +02:00
hv
iio
include selftests: line buffer test program's stdout 2023-08-18 10:12:42 -07:00
io_uring
kvm/kvm_stat
laptop
leds
lib libsubcmd: Avoid SEGV/use-after-free when commands aren't excluded 2023-07-11 16:44:12 -03:00
memory-model LKMM scripting updates for v6.4 2023-04-24 12:02:25 -07:00
mm slab changes for 6.4 2023-04-25 13:00:41 -07:00
net/ynl tools: ynl-gen: fix parse multi-attr enum attribute 2023-07-26 13:38:23 -07:00
objtool objtool: initialize all of struct elf 2023-07-10 09:52:28 +02:00
pci
pcmcia
perf perf test task_exit: No need for a cycles event to check if we get an PERF_RECORD_EXIT 2023-07-17 10:27:44 -03:00
power platform-drivers-x86 for v6.5-1 2023-06-30 14:50:00 -07:00
rcu
scripts sh updates for v6.4 2023-04-27 17:41:23 -07:00
spi spi: spidev_test Add three missing spi mode bits 2023-05-30 15:20:12 +01:00
testing selftests: line buffer test program's stdout 2023-08-18 10:12:42 -07:00
thermal
time
tracing rtla/timerlat_hist: Add timerlat user-space support 2023-06-13 16:41:14 -04:00
usb usbip: Use _FORTIFY_SOURCE=2 instead of (implicitly) =1 2023-05-29 15:11:30 +01:00
verification rv: Fix addition on an uninitialized variable 'run' 2023-04-25 17:02:13 -04:00
virtio tools/virtio: fix build break for aarch64 2023-06-27 10:47:08 -04:00
wmi
workqueue workqueue: Track and monitor per-workqueue CPU time usage 2023-05-17 17:02:09 -10:00
Makefile