5 Commits

Author SHA1 Message Date
Roman Penyaev
474328c06e kselftests: introduce new epoll60 testcase for catching lost wakeups
This test case catches lost wake up introduced by commit 339ddb53d373
("fs/epoll: remove unnecessary wakeups of nested epoll")

The test is simple: we have 10 threads and 10 event fds.  Each thread
can harvest only 1 event.  1 producer fires all 10 events at once and
waits that all 10 events will be observed by 10 threads.

In case of lost wakeup epoll_wait() will timeout and 0 will be returned.

Test case catches two sort of problems: forgotten wakeup on event, which
hits the ->ovflist list, this problem was fixed by:

  5a2513239750 ("eventpoll: fix missing wakeup for ovflist in ep_poll_callback")

the other problem is when several sequential events hit the same waiting
thread, thus other waiters get no wakeups.  Problem is fixed in the
following patch.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Khazhismel Kumykov <khazhy@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Heiher <r@hev.cc>
Cc: Jason Baron <jbaron@akamai.com>
Link: http://lkml.kernel.org/r/20200430130326.1368509-1-rpenyaev@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-07 19:27:21 -07:00
Roman Penyaev
282144e04b kselftest: introduce new epoll test case
This testcase repeats epollbug.c from the bug:

  https://bugzilla.kernel.org/show_bug.cgi?id=205933

What it tests?  It tests the race between epoll_ctl() and epoll_wait().
New event mask passed to epoll_ctl() triggers wake up, which can be missed
because of the bug described in the link.  Reproduction is 100%, so easy
to fix.  Kudos, Max, for wonderful test case.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Max Neunhoeffer <max@arangodb.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Christopher Kohlhoff <chris.kohlhoff@clearpool.io>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jes Sorensen <jes.sorensen@gmail.com>
Link: http://lkml.kernel.org/r/20200214170211.561524-2-rpenyaev@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Masahiro Yamada
d198b34f38 .gitignore: add SPDX License Identifier
Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-25 11:50:48 +01:00
Shuah Khan
7648dd9fc9 selftests: filesystems/epoll: fix build error
epoll build fails to find pthread lib. Fix Makefile to use LDLIBS
instead of LDFLAGS. LDLIBS is the right flag to use here with -l
option when invoking ld.

gcc -I../../../../../usr/include/  -lpthread  epoll_wakeup_test.c  -o .../tools/testing/selftests/filesystems/epoll/epoll_wakeup_test
/usr/bin/ld: /tmp/ccaZvJUl.o: in function `kill_timeout':
epoll_wakeup_test.c:(.text+0x4dd): undefined reference to `pthread_kill'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x4f2): undefined reference to `pthread_kill'
/usr/bin/ld: /tmp/ccaZvJUl.o: in function `epoll9':
epoll_wakeup_test.c:(.text+0x6382): undefined reference to `pthread_create'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x64d2): undefined reference to `pthread_create'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x6626): undefined reference to `pthread_join'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x684c): undefined reference to `pthread_tryjoin_np'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x6864): undefined reference to `pthread_kill'
/usr/bin/ld: epoll_wakeup_test.c:(.text+0x6878): undefined reference to `pthread_join'

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-12-23 10:52:40 -07:00
Heiher
f2728fe80c selftests: add epoll selftests
This adds the promised selftest for epoll.  It will verify the wakeups
of epoll.  Including leaf and nested mode, epoll_wait() and poll() and
multi-threads.

Link: http://lkml.kernel.org/r/20191009121518.4027-1-r@hev.cc
Signed-off-by: hev <r@hev.cc>
Reviewed-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:13 -08:00