* selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices @ 2020-09-23 14:22 Naresh Kamboju 2020-09-24 14:33 ` Christian Brauner 0 siblings, 1 reply; 6+ messages in thread From: Naresh Kamboju @ 2020-09-23 14:22 UTC (permalink / raw) To: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list Cc: Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Christian Brauner, Shuah Khan, lkft-triage selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, i386 and arm64 Juno-r2 These devices are using NFS mounted rootfs. I have tested pidfd testcases independently and all test PASS. The Hang or exit from test run noticed when run by run_kselftest.sh pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL) (-1) == 0 (0) wait_nonblock: Test terminated by assertion metadata: git branch: master git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git commit: e64997027d5f171148687e58b78c8b3c869a6158 git describe: next-20200922 make_kernelversion: 5.9.0-rc6 kernel-config: http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Test output log: --------------------- [ 1385.104983] audit: type=1701 audit(1600804535.960:87865): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=31268 comm=\"pidfd_wait\" exe=\"/opt/kselftests/default-in-kernel/pidfd/pidfd_wait\" sig=6 res=1 # selftests: pidfd: pidfd_wait # TAP version 13 # 1..3 # # Starting 3 tests from 1 test cases. # # RUN global.wait_simple ... # # OK global.wait_simple # ok 1 global.wait_simple # # RUN global.wait_states ... # # OK global.wait_states # ok 2 global.wait_states # # RUN global.wait_nonblock ... # # pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL) (-1) == 0 (0) # # wait_nonblock: Test terminated by assertion # # FAIL global.wait_nonblock # not ok 3 global.wait_nonblock # # FAILED: 2 / 3 tests passed. # # Totals: pass:2 fail:1 xfail:0 xpass:0 skip:0 error:0 Marking unfinished test run as failed ref: https://lkft.validation.linaro.org/scheduler/job/1782129#L11737 https://lkft.validation.linaro.org/scheduler/job/1782130#L12735 https://lkft.validation.linaro.org/scheduler/job/1782138#L14178 -- Linaro LKFT https://lkft.linaro.org ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices 2020-09-23 14:22 selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices Naresh Kamboju @ 2020-09-24 14:33 ` Christian Brauner 2020-09-24 16:21 ` Christian Brauner 0 siblings, 1 reply; 6+ messages in thread From: Christian Brauner @ 2020-09-24 14:33 UTC (permalink / raw) To: Naresh Kamboju Cc: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list, Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Shuah Khan, lkft-triage On Wed, Sep 23, 2020 at 07:52:05PM +0530, Naresh Kamboju wrote: > selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, > i386 and arm64 Juno-r2 > These devices are using NFS mounted rootfs. > I have tested pidfd testcases independently and all test PASS. > > The Hang or exit from test run noticed when run by run_kselftest.sh > > pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, > &info, WSTOPPED, NULL) (-1) == 0 (0) > wait_nonblock: Test terminated by assertion > > metadata: > git branch: master > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > git commit: e64997027d5f171148687e58b78c8b3c869a6158 > git describe: next-20200922 > make_kernelversion: 5.9.0-rc6 > kernel-config: > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config > > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Thanks for reproting this. I'm taking a look now! Christian https://lkft.linaro.org ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices 2020-09-24 14:33 ` Christian Brauner @ 2020-09-24 16:21 ` Christian Brauner 2020-09-25 6:09 ` Naresh Kamboju 2020-10-02 17:31 ` Naresh Kamboju 0 siblings, 2 replies; 6+ messages in thread From: Christian Brauner @ 2020-09-24 16:21 UTC (permalink / raw) To: Naresh Kamboju Cc: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list, Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Shuah Khan, lkft-triage On Thu, Sep 24, 2020 at 04:33:17PM +0200, Christian Brauner wrote: > On Wed, Sep 23, 2020 at 07:52:05PM +0530, Naresh Kamboju wrote: > > selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, > > i386 and arm64 Juno-r2 > > These devices are using NFS mounted rootfs. > > I have tested pidfd testcases independently and all test PASS. > > > > The Hang or exit from test run noticed when run by run_kselftest.sh > > > > pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, > > &info, WSTOPPED, NULL) (-1) == 0 (0) > > wait_nonblock: Test terminated by assertion > > > > metadata: > > git branch: master > > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > git commit: e64997027d5f171148687e58b78c8b3c869a6158 > > git describe: next-20200922 > > make_kernelversion: 5.9.0-rc6 > > kernel-config: > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config > > > > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> > > Thanks for reproting this. I'm taking a look now! Ok, this is a simple race in the selftests, that I overlooked and which is more likely to hit when there's a lot of processes running on the system. Basically the child process hasn't SIGSTOPed itself yet but the parent is already calling waitid() on a O_NONBLOCK pidfd. Since it doesn't find a WSTOPPED process it returns -EAGAIN correctly. The fix for this is to move the line where we're removing the O_NONBLOCK property from the fd before the waitid() WSTOPPED call so we hang until the child becomes stopped. So I believe the fix is: diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c index 4063d6f31fa4..be2943f072f6 100644 --- a/tools/testing/selftests/pidfd/pidfd_wait.c +++ b/tools/testing/selftests/pidfd/pidfd_wait.c @@ -205,6 +205,8 @@ TEST(wait_nonblock) ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED | WNOHANG, NULL); ASSERT_EQ(ret, 0); + ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); + ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0); ASSERT_EQ(info.si_signo, SIGCHLD); ASSERT_EQ(info.si_code, CLD_STOPPED); @@ -212,8 +214,6 @@ TEST(wait_nonblock) ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0); - ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); - ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL), 0); ASSERT_EQ(info.si_signo, SIGCHLD); ASSERT_EQ(info.si_code, CLD_EXITED); Christian ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices 2020-09-24 16:21 ` Christian Brauner @ 2020-09-25 6:09 ` Naresh Kamboju 2020-10-02 17:31 ` Naresh Kamboju 1 sibling, 0 replies; 6+ messages in thread From: Naresh Kamboju @ 2020-09-25 6:09 UTC (permalink / raw) To: Christian Brauner Cc: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list, Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Shuah Khan, lkft-triage On Thu, 24 Sep 2020 at 21:51, Christian Brauner <christian.brauner@ubuntu.com> wrote: > > On Thu, Sep 24, 2020 at 04:33:17PM +0200, Christian Brauner wrote: > > On Wed, Sep 23, 2020 at 07:52:05PM +0530, Naresh Kamboju wrote: > > > selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, > > > i386 and arm64 Juno-r2 > > > These devices are using NFS mounted rootfs. > > > I have tested pidfd testcases independently and all test PASS. > > > > > > The Hang or exit from test run noticed when run by run_kselftest.sh > > > > > > pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, > > > &info, WSTOPPED, NULL) (-1) == 0 (0) > > > wait_nonblock: Test terminated by assertion > > > > > > metadata: > > > git branch: master > > > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > > git commit: e64997027d5f171148687e58b78c8b3c869a6158 > > > git describe: next-20200922 > > > make_kernelversion: 5.9.0-rc6 > > > kernel-config: > > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config > > > > > > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> > > > > Thanks for reproting this. I'm taking a look now! > > Ok, this is a simple race in the selftests, that I overlooked and which > is more likely to hit when there's a lot of processes running on the > system. Basically the child process hasn't SIGSTOPed itself yet but the > parent is already calling waitid() on a O_NONBLOCK pidfd. Since it > doesn't find a WSTOPPED process it returns -EAGAIN correctly. > > The fix for this is to move the line where we're removing the O_NONBLOCK > property from the fd before the waitid() WSTOPPED call so we hang until > the child becomes stopped. > > So I believe the fix is: This patch applied and scheduled for kselftest full test run. > > diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c > index 4063d6f31fa4..be2943f072f6 100644 > --- a/tools/testing/selftests/pidfd/pidfd_wait.c > +++ b/tools/testing/selftests/pidfd/pidfd_wait.c > @@ -205,6 +205,8 @@ TEST(wait_nonblock) > ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED | WNOHANG, NULL); > ASSERT_EQ(ret, 0); > > + ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); > + > ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0); > ASSERT_EQ(info.si_signo, SIGCHLD); > ASSERT_EQ(info.si_code, CLD_STOPPED); > @@ -212,8 +214,6 @@ TEST(wait_nonblock) > > ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0); > > - ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); > - > ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL), 0); > ASSERT_EQ(info.si_signo, SIGCHLD); > ASSERT_EQ(info.si_code, CLD_EXITED); > > Christian - Naresh ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices 2020-09-24 16:21 ` Christian Brauner 2020-09-25 6:09 ` Naresh Kamboju @ 2020-10-02 17:31 ` Naresh Kamboju 2020-10-09 9:58 ` Christian Brauner 1 sibling, 1 reply; 6+ messages in thread From: Naresh Kamboju @ 2020-10-02 17:31 UTC (permalink / raw) To: Christian Brauner Cc: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list, Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Shuah Khan, lkft-triage On Thu, 24 Sep 2020 at 21:51, Christian Brauner <christian.brauner@ubuntu.com> wrote: > > On Thu, Sep 24, 2020 at 04:33:17PM +0200, Christian Brauner wrote: > > On Wed, Sep 23, 2020 at 07:52:05PM +0530, Naresh Kamboju wrote: > > > selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, > > > i386 and arm64 Juno-r2 > > > These devices are using NFS mounted rootfs. > > > I have tested pidfd testcases independently and all test PASS. > > > > > > The Hang or exit from test run noticed when run by run_kselftest.sh > > > > > > pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, > > > &info, WSTOPPED, NULL) (-1) == 0 (0) > > > wait_nonblock: Test terminated by assertion > > > > > > metadata: > > > git branch: master > > > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > > git commit: e64997027d5f171148687e58b78c8b3c869a6158 > > > git describe: next-20200922 > > > make_kernelversion: 5.9.0-rc6 > > > kernel-config: > > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config > > > > > > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> > > > > Thanks for reproting this. I'm taking a look now! > > Ok, this is a simple race in the selftests, that I overlooked and which > is more likely to hit when there's a lot of processes running on the > system. Basically the child process hasn't SIGSTOPed itself yet but the > parent is already calling waitid() on a O_NONBLOCK pidfd. Since it > doesn't find a WSTOPPED process it returns -EAGAIN correctly. > > The fix for this is to move the line where we're removing the O_NONBLOCK > property from the fd before the waitid() WSTOPPED call so we hang until > the child becomes stopped. > > So I believe the fix is: I have tested this patch and the pidfd_wait test did not hang this time. Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> test log link https://lkft.validation.linaro.org/scheduler/job/1813223 > > diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c > index 4063d6f31fa4..be2943f072f6 100644 > --- a/tools/testing/selftests/pidfd/pidfd_wait.c > +++ b/tools/testing/selftests/pidfd/pidfd_wait.c > @@ -205,6 +205,8 @@ TEST(wait_nonblock) > ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED | WNOHANG, NULL); > ASSERT_EQ(ret, 0); > > + ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); > + > ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0); > ASSERT_EQ(info.si_signo, SIGCHLD); > ASSERT_EQ(info.si_code, CLD_STOPPED); > @@ -212,8 +214,6 @@ TEST(wait_nonblock) > > ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0); > > - ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0); > - > ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL), 0); > ASSERT_EQ(info.si_signo, SIGCHLD); > ASSERT_EQ(info.si_code, CLD_EXITED); > - Naresh > Christian ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices 2020-10-02 17:31 ` Naresh Kamboju @ 2020-10-09 9:58 ` Christian Brauner 0 siblings, 0 replies; 6+ messages in thread From: Christian Brauner @ 2020-10-09 9:58 UTC (permalink / raw) To: Naresh Kamboju Cc: open list:KERNEL SELFTEST FRAMEWORK, linux-api, open list, Christian Brauner, Kees Cook, Peter Zijlstra (Intel), Ingo Molnar, Thomas Gleixner, Oleg Nesterov, Eric W. Biederman, Sargun Dhillon, Aleksa Sarai, Josh Triplett, Jens Axboe, Shuah Khan, lkft-triage On Fri, Oct 02, 2020 at 11:01:34PM +0530, Naresh Kamboju wrote: > On Thu, 24 Sep 2020 at 21:51, Christian Brauner > <christian.brauner@ubuntu.com> wrote: > > > > On Thu, Sep 24, 2020 at 04:33:17PM +0200, Christian Brauner wrote: > > > On Wed, Sep 23, 2020 at 07:52:05PM +0530, Naresh Kamboju wrote: > > > > selftests: pidfd: pidfd_wait hangs on linux next kernel on x86_64, > > > > i386 and arm64 Juno-r2 > > > > These devices are using NFS mounted rootfs. > > > > I have tested pidfd testcases independently and all test PASS. > > > > > > > > The Hang or exit from test run noticed when run by run_kselftest.sh > > > > > > > > pidfd_wait.c:208:wait_nonblock:Expected sys_waitid(P_PIDFD, pidfd, > > > > &info, WSTOPPED, NULL) (-1) == 0 (0) > > > > wait_nonblock: Test terminated by assertion > > > > > > > > metadata: > > > > git branch: master > > > > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > > > git commit: e64997027d5f171148687e58b78c8b3c869a6158 > > > > git describe: next-20200922 > > > > make_kernelversion: 5.9.0-rc6 > > > > kernel-config: > > > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/865/config > > > > > > > > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> > > > > > > Thanks for reproting this. I'm taking a look now! > > > > Ok, this is a simple race in the selftests, that I overlooked and which > > is more likely to hit when there's a lot of processes running on the > > system. Basically the child process hasn't SIGSTOPed itself yet but the > > parent is already calling waitid() on a O_NONBLOCK pidfd. Since it > > doesn't find a WSTOPPED process it returns -EAGAIN correctly. > > > > The fix for this is to move the line where we're removing the O_NONBLOCK > > property from the fd before the waitid() WSTOPPED call so we hang until > > the child becomes stopped. > > > > So I believe the fix is: > > I have tested this patch and the pidfd_wait test did not hang this time. > > Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> > > test log link > https://lkft.validation.linaro.org/scheduler/job/1813223 Thanks for testing, Naresh. I've applied the patch: https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/commit/?h=pidfd_o_nonblock&id=01361b665a26ef0c087e53f14cf310d1cfe0cf98 Christian ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-10-09 9:58 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2020-09-23 14:22 selftests: pidfd: pidfd_wait hangs on linux next kernel on all devices Naresh Kamboju 2020-09-24 14:33 ` Christian Brauner 2020-09-24 16:21 ` Christian Brauner 2020-09-25 6:09 ` Naresh Kamboju 2020-10-02 17:31 ` Naresh Kamboju 2020-10-09 9:58 ` Christian Brauner
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