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| author | Roman Penyaev <rpenyaev@suse.de> | 2020-04-06 20:11:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-07 10:43:44 -0700 |
| commit | 282144e04b9a88b53dc16dc46e47f7d810e0b63b (patch) | |
| tree | ded3c2b80e095af23dec7ac9e88ea0c1df4b0327 /tools/testing | |
| parent | 16b7f3c89907acf947500f0c20dcff44f651d795 (diff) | |
| download | linux-stable-282144e04b9a88b53dc16dc46e47f7d810e0b63b.tar.gz linux-stable-282144e04b9a88b53dc16dc46e47f7d810e0b63b.tar.bz2 linux-stable-282144e04b9a88b53dc16dc46e47f7d810e0b63b.zip | |
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>
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c | 67 |
1 files changed, 66 insertions, 1 deletions
diff --git a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c index 37a04dab56f0..11eee0b60040 100644 --- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c +++ b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c @@ -7,13 +7,14 @@ #include <pthread.h> #include <sys/epoll.h> #include <sys/socket.h> +#include <sys/eventfd.h> #include "../../kselftest_harness.h" struct epoll_mtcontext { int efd[3]; int sfd[4]; - int count; + volatile int count; pthread_t main; pthread_t waiter; @@ -3071,4 +3072,68 @@ TEST(epoll58) close(ctx.sfd[3]); } +static void *epoll59_thread(void *ctx_) +{ + struct epoll_mtcontext *ctx = ctx_; + struct epoll_event e; + int i; + + for (i = 0; i < 100000; i++) { + while (ctx->count == 0) + ; + + e.events = EPOLLIN | EPOLLERR | EPOLLET; + epoll_ctl(ctx->efd[0], EPOLL_CTL_MOD, ctx->sfd[0], &e); + ctx->count = 0; + } + + return NULL; +} + +/* + * t0 + * (p) \ + * e0 + * (et) / + * e0 + * + * Based on https://bugzilla.kernel.org/show_bug.cgi?id=205933 + */ +TEST(epoll59) +{ + pthread_t emitter; + struct pollfd pfd; + struct epoll_event e; + struct epoll_mtcontext ctx = { 0 }; + int i, ret; + + signal(SIGUSR1, signal_handler); + + ctx.efd[0] = epoll_create1(0); + ASSERT_GE(ctx.efd[0], 0); + + ctx.sfd[0] = eventfd(1, 0); + ASSERT_GE(ctx.sfd[0], 0); + + e.events = EPOLLIN | EPOLLERR | EPOLLET; + ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0); + + ASSERT_EQ(pthread_create(&emitter, NULL, epoll59_thread, &ctx), 0); + + for (i = 0; i < 100000; i++) { + ret = epoll_wait(ctx.efd[0], &e, 1, 1000); + ASSERT_GT(ret, 0); + + while (ctx.count != 0) + ; + ctx.count = 1; + } + if (pthread_tryjoin_np(emitter, NULL) < 0) { + pthread_kill(emitter, SIGUSR1); + pthread_join(emitter, NULL); + } + close(ctx.efd[0]); + close(ctx.sfd[0]); +} + TEST_HARNESS_MAIN |