Bug 244053

Summary:	`dtrace -c` causes program dumps core after somewhere between (r357694, r357701]
Product:	Base System	Reporter:	Li-Wen Hsu <lwhsu>
Component:	bin	Assignee:	freebsd-dtrace (Nobody) <dtrace>
Status:	Closed FIXED
Severity:	Affects Many People	CC:	asomers, dtrace, markj
Priority:	---	Keywords:	crash, needs-qa, regression
Version:	CURRENT
Hardware:	Any
OS:	Any

Description Li-Wen Hsu freebsd_committer

2020-02-11 22:14:17 UTC

root@:~ # uname -a
FreeBSD  13.0-CURRENT FreeBSD 13.0-CURRENT #0 r357694: Sun Feb  9 12:40:40 UTC 2020     root@FreeBSD-head-amd64-build.jail.ci.FreeBSD.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC  amd64
root@:~ # dtrace -n 'syscall:::entry { @[execname, probefunc] = count(); }' -c "echo hello"
dtrace: description 'syscall:::entry ' matched 1130 probes
dtrace: buffer size lowered to 1m
dtrace: aggregation size lowered to 1m
hello
dtrace: pid 825 has exited

  dtrace                                              close                                                             1
  dtrace                                              fstat                                                             1
  dtrace                                              open                                                              1
  dtrace                                              thr_exit                                                          1
  echo                                                cap_enter                                                         1
  echo                                                exit                                                              1
  echo                                                mmap                                                              1
  echo                                                mprotect                                                          1
  echo                                                writev                                                            1
  dtrace                                              _umtx_op                                                          2
  dtrace                                              mmap                                                              3
  echo                                                cap_fcntls_limit                                                  3
  echo                                                cap_ioctls_limit                                                  3
  echo                                                cap_rights_limit                                                  3
  dtrace                                              wait4                                                             4
  dtrace                                              __sysctl                                                          5
  dtrace                                              write                                                             6
  echo                                                sigprocmask                                                       7
  dtrace                                              sigaction                                                        10
  dtrace                                              __sysctlbyname                                                   17
  dtrace                                              sigprocmask                                                      20
  dtrace                                              ptrace                                                           22
  dtrace                                              ioctl                                                            41



root@:~ # uname -a
FreeBSD  13.0-CURRENT FreeBSD 13.0-CURRENT #0 r357701: Sun Feb  9 13:32:35 UTC 2020     root@FreeBSD-head-amd64-build.jail.ci.FreeBSD.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC  amd64
root@:~ # dtrace -n 'syscall:::entry { @[execname, probefunc] = count(); }' -c "echo hello"
dtrace: failed to control pid 800: process died from signal 11
root@:~ # dtrace -n 'syscall:::entry { @[execname, probefunc] = count(); }' -c "ls /"
dtrace: failed to control pid 790: process died from signal 11
root@:~ # lldb /usr/lib/debug/bin/ls.debug -c ls.core 
(lldb) target create "/usr/lib/debug/bin/ls.debug" --core "ls.core"
Core file '/root/ls.core' (x86_64) was loaded.
(lldb) bt
* thread #1, name = 'ls', stop reason = signal SIGSEGV
  * frame #0: 0x0000000000000000

Comment 1 commit-hook freebsd_committer

2020-02-11 22:21:49 UTC

A commit references this bug:

Author: lwhsu
Date: Tue Feb 11 22:21:22 UTC 2020
New revision: 357780
URL: https://svnweb.freebsd.org/changeset/base/357780

Log:
  Temporarily skip sys.geom.class.multipath.failloop.failloop in CI

  This case uses `dtrace -c` but it has some issues at the moment

  PR:		244053
  Sponsored by:	The FreeBSD Foundation

Changes:
  head/tests/sys/geom/class/multipath/failloop.sh

Comment 2 Alan Somers freebsd_committer

2020-05-03 18:16:34 UTC

I can't reproduce this failure locally at r360076M.  Was it fixed, or is this crash only reproducible in the CI environment?

Comment 3 Li-Wen Hsu freebsd_committer

2020-05-18 23:40:23 UTC

(In reply to Alan Somers from comment #2)
From bisect in artifact, this is fixed somewhere between (r358152, r358178]

Comment 4 commit-hook freebsd_committer

2020-05-18 23:43:53 UTC

A commit references this bug:

Author: lwhsu
Date: Mon May 18 23:43:48 UTC 2020
New revision: 361229
URL: https://svnweb.freebsd.org/changeset/base/361229

Log:
  Revert 357780, `dtrace -c` has been fixed in head`

  PR:		244053
  Sponsored by:	The FreeBSD Foundation

Changes:
  head/tests/sys/geom/class/multipath/failloop.sh

Comment 5 Mark Johnston freebsd_committer

2020-06-15 21:22:44 UTC

I suspect this is fixed by r360979.  The bug was exposed by an LLVM update I believe.  Please re-open if it is reproducible with that revision.