Re: [linux-next:master 9345/10049] kernel/signal.c:2331:39: sparse: sparse: incorrect type in argument 1 (different address spaces)

[Suren Baghdasaryan <surenb@google.com>]

On Tue, Jul 2, 2024 at 9:46 AM kernel test robot <lkp@intel.com> wrote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   82e4255305c554b0bb18b7ccf2db86041b4c8b6e
> commit: ea929eb9121588cec720649ebac3caf75bab2df0 [9345/10049] signal: on exit skip waiting for an ack from the tracer if it is frozen
> config: x86_64-randconfig-123-20240702 (https://download.01.org/0day-ci/archive/20240702/202407021700.qhDbFwso-lkp@intel.com/config)
> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240702/202407021700.qhDbFwso-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202407021700.qhDbFwso-lkp@intel.com/
>
> sparse warnings: (new ones prefixed by >>)
>    kernel/signal.c: note: in included file (through arch/x86/include/uapi/asm/signal.h, arch/x86/include/asm/signal.h, include/uapi/linux/signal.h, ...):
>    include/uapi/asm-generic/signal-defs.h:83:29: sparse: sparse: multiple address spaces given
>    kernel/signal.c:188:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:188:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:188:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:191:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:191:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:191:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:473:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:473:9: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:473:9: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:477:34: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:477:34: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:477:34: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:510:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:510:9: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:510:9: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:513:36: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:513:36: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:513:36: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:535:53: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected struct k_sigaction *ka @@     got struct k_sigaction [noderef] __rcu * @@
>    kernel/signal.c:535:53: sparse:     expected struct k_sigaction *ka
>    kernel/signal.c:535:53: sparse:     got struct k_sigaction [noderef] __rcu *
>    include/uapi/asm-generic/signal-defs.h:83:29: sparse: sparse: multiple address spaces given
>    kernel/signal.c:695:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:695:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:695:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:697:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:697:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:697:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:762:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct lockdep_map const *lock @@     got struct lockdep_map [noderef] __rcu * @@
>    kernel/signal.c:762:9: sparse:     expected struct lockdep_map const *lock
>    kernel/signal.c:762:9: sparse:     got struct lockdep_map [noderef] __rcu *
>    kernel/signal.c:887:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct lockdep_map const *lock @@     got struct lockdep_map [noderef] __rcu * @@
>    kernel/signal.c:887:9: sparse:     expected struct lockdep_map const *lock
>    kernel/signal.c:887:9: sparse:     got struct lockdep_map [noderef] __rcu *
>    kernel/signal.c:1082:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct lockdep_map const *lock @@     got struct lockdep_map [noderef] __rcu * @@
>    kernel/signal.c:1082:9: sparse:     expected struct lockdep_map const *lock
>    kernel/signal.c:1082:9: sparse:     got struct lockdep_map [noderef] __rcu *
>    kernel/signal.c:1334:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:1334:9: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:1334:9: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:1335:16: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct k_sigaction *action @@     got struct k_sigaction [noderef] __rcu * @@
>    kernel/signal.c:1335:16: sparse:     expected struct k_sigaction *action
>    kernel/signal.c:1335:16: sparse:     got struct k_sigaction [noderef] __rcu *
>    kernel/signal.c:1356:34: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:1356:34: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:1356:34: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:1944:36: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:1944:36: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:1944:36: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2074:44: sparse: sparse: cast removes address space '__rcu' of expression
>    kernel/signal.c:2093:65: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct task_struct *tsk @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2093:65: sparse:     expected struct task_struct *tsk
>    kernel/signal.c:2093:65: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2094:40: sparse: sparse: cast removes address space '__rcu' of expression
>    kernel/signal.c:2112:14: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct sighand_struct *psig @@     got struct sighand_struct [noderef] __rcu *[noderef] __rcu sighand @@
>    kernel/signal.c:2112:14: sparse:     expected struct sighand_struct *psig
>    kernel/signal.c:2112:14: sparse:     got struct sighand_struct [noderef] __rcu *[noderef] __rcu sighand
>    kernel/signal.c:2141:53: sparse: sparse: incorrect type in argument 3 (different address spaces) @@     expected struct task_struct *t @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2141:53: sparse:     expected struct task_struct *t
>    kernel/signal.c:2141:53: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2142:34: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected struct task_struct *parent @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2142:34: sparse:     expected struct task_struct *parent
>    kernel/signal.c:2142:34: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2171:24: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct task_struct *parent @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2171:24: sparse:     expected struct task_struct *parent
>    kernel/signal.c:2171:24: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2174:24: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct task_struct *parent @@     got struct task_struct [noderef] __rcu *real_parent @@
>    kernel/signal.c:2174:24: sparse:     expected struct task_struct *parent
>    kernel/signal.c:2174:24: sparse:     got struct task_struct [noderef] __rcu *real_parent
>    kernel/signal.c:2207:17: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct sighand_struct *sighand @@     got struct sighand_struct [noderef] __rcu *sighand @@
>    kernel/signal.c:2207:17: sparse:     expected struct sighand_struct *sighand
>    kernel/signal.c:2207:17: sparse:     got struct sighand_struct [noderef] __rcu *sighand
>    kernel/signal.c:2247:41: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2247:41: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2247:41: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2249:39: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2249:39: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2249:39: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2306:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2306:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2306:33: sparse:     got struct spinlock [noderef] __rcu *
> >> kernel/signal.c:2331:39: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct task_struct *task @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2331:39: sparse:     expected struct task_struct *task
>    kernel/signal.c:2331:39: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2378:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2378:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2378:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2418:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2418:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2418:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2420:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2420:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2420:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2518:41: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2518:41: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2518:41: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2602:41: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2602:41: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2602:41: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2614:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:2614:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:2614:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:2649:52: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct task_struct *tsk @@     got struct task_struct [noderef] __rcu *parent @@
>    kernel/signal.c:2649:52: sparse:     expected struct task_struct *tsk
>    kernel/signal.c:2649:52: sparse:     got struct task_struct [noderef] __rcu *parent
>    kernel/signal.c:2651:49: sparse: sparse: cast removes address space '__rcu' of expression
>    kernel/signal.c:2689:49: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected struct sighand_struct *sighand @@     got struct sighand_struct [noderef] __rcu *sighand @@
>    kernel/signal.c:2689:49: sparse:     expected struct sighand_struct *sighand
>    kernel/signal.c:2689:49: sparse:     got struct sighand_struct [noderef] __rcu *sighand
>    kernel/signal.c:3023:27: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3023:27: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3023:27: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3044:29: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3044:29: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3044:29: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3111:27: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3111:27: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3111:27: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3113:29: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3113:29: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3113:29: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3264:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3264:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3264:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3267:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3267:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3267:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3656:27: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3656:27: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3656:27: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3668:37: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3668:37: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3668:37: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3673:35: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3673:35: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3673:35: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:3678:29: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:3678:29: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:3678:29: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:4154:31: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:4154:31: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:4154:31: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:4166:33: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:4166:33: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:4166:33: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:4184:11: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct k_sigaction *k @@     got struct k_sigaction [noderef] __rcu * @@
>    kernel/signal.c:4184:11: sparse:     expected struct k_sigaction *k
>    kernel/signal.c:4184:11: sparse:     got struct k_sigaction [noderef] __rcu *
>    kernel/signal.c:4186:25: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:4186:25: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:4186:25: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:4188:35: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:4188:35: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:4188:35: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:4236:27: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    kernel/signal.c:4236:27: sparse:     expected struct spinlock [usertype] *lock
>    kernel/signal.c:4236:27: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:72:34: sparse: sparse: dereference of noderef expression
>    kernel/signal.c:522:35: sparse: sparse: dereference of noderef expression
>    kernel/signal.c:550:52: sparse: sparse: dereference of noderef expression
>    kernel/signal.c:1035:13: sparse: sparse: dereference of noderef expression
>    kernel/signal.c: note: in included file:
>    include/linux/signalfd.h:21:13: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct wait_queue_head *wq_head @@     got struct wait_queue_head [noderef] __rcu * @@
>    include/linux/signalfd.h:21:13: sparse:     expected struct wait_queue_head *wq_head
>    include/linux/signalfd.h:21:13: sparse:     got struct wait_queue_head [noderef] __rcu *
>    include/linux/signalfd.h:22:17: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct wait_queue_head *wq_head @@     got struct wait_queue_head [noderef] __rcu * @@
>    include/linux/signalfd.h:22:17: sparse:     expected struct wait_queue_head *wq_head
>    include/linux/signalfd.h:22:17: sparse:     got struct wait_queue_head [noderef] __rcu *
>    kernel/signal.c: note: in included file (through include/linux/smp.h, include/linux/lockdep.h, include/linux/spinlock.h, ...):
>    include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
>    kernel/signal.c: note: in included file (through include/linux/sched/cputime.h):
>    include/linux/sched/signal.h:754:37: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    include/linux/sched/signal.h:754:37: sparse:     expected struct spinlock [usertype] *lock
>    include/linux/sched/signal.h:754:37: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c:1305:9: sparse: sparse: context imbalance in 'do_send_sig_info' - different lock contexts for basic block
>    kernel/signal.c: note: in included file (through include/linux/rbtree.h, include/linux/mm_types.h, include/linux/mmzone.h, ...):
>    include/linux/rcupdate.h:809:9: sparse: sparse: context imbalance in '__lock_task_sighand' - different lock contexts for basic block
>    kernel/signal.c: note: in included file (through include/linux/sched/cputime.h):
>    include/linux/sched/signal.h:754:37: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected struct spinlock [usertype] *lock @@     got struct spinlock [noderef] __rcu * @@
>    include/linux/sched/signal.h:754:37: sparse:     expected struct spinlock [usertype] *lock
>    include/linux/sched/signal.h:754:37: sparse:     got struct spinlock [noderef] __rcu *
>    kernel/signal.c: note: in included file:
>
> vim +2331 kernel/signal.c
>
>   2218
>   2219  /*
>   2220   * This must be called with current->sighand->siglock held.
>   2221   *
>   2222   * This should be the path for all ptrace stops.
>   2223   * We always set current->last_siginfo while stopped here.
>   2224   * That makes it a way to test a stopped process for
>   2225   * being ptrace-stopped vs being job-control-stopped.
>   2226   *
>   2227   * Returns the signal the ptracer requested the code resume
>   2228   * with.  If the code did not stop because the tracer is gone,
>   2229   * the stop signal remains unchanged unless clear_code.
>   2230   */
>   2231  static int ptrace_stop(int exit_code, int why, unsigned long message,
>   2232                         kernel_siginfo_t *info)
>   2233          __releases(&current->sighand->siglock)
>   2234          __acquires(&current->sighand->siglock)
>   2235  {
>   2236          bool gstop_done = false;
>   2237
>   2238          if (arch_ptrace_stop_needed()) {
>   2239                  /*
>   2240                   * The arch code has something special to do before a
>   2241                   * ptrace stop.  This is allowed to block, e.g. for faults
>   2242                   * on user stack pages.  We can't keep the siglock while
>   2243                   * calling arch_ptrace_stop, so we must release it now.
>   2244                   * To preserve proper semantics, we must do this before
>   2245                   * any signal bookkeeping like checking group_stop_count.
>   2246                   */
>   2247                  spin_unlock_irq(&current->sighand->siglock);
>   2248                  arch_ptrace_stop();
>   2249                  spin_lock_irq(&current->sighand->siglock);
>   2250          }
>   2251
>   2252          /*
>   2253           * After this point ptrace_signal_wake_up or signal_wake_up
>   2254           * will clear TASK_TRACED if ptrace_unlink happens or a fatal
>   2255           * signal comes in.  Handle previous ptrace_unlinks and fatal
>   2256           * signals here to prevent ptrace_stop sleeping in schedule.
>   2257           */
>   2258          if (!current->ptrace || __fatal_signal_pending(current))
>   2259                  return exit_code;
>   2260
>   2261          set_special_state(TASK_TRACED);
>   2262          current->jobctl |= JOBCTL_TRACED;
>   2263
>   2264          /*
>   2265           * We're committing to trapping.  TRACED should be visible before
>   2266           * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
>   2267           * Also, transition to TRACED and updates to ->jobctl should be
>   2268           * atomic with respect to siglock and should be done after the arch
>   2269           * hook as siglock is released and regrabbed across it.
>   2270           *
>   2271           *     TRACER                               TRACEE
>   2272           *
>   2273           *     ptrace_attach()
>   2274           * [L]   wait_on_bit(JOBCTL_TRAPPING)   [S] set_special_state(TRACED)
>   2275           *     do_wait()
>   2276           *       set_current_state()                smp_wmb();
>   2277           *       ptrace_do_wait()
>   2278           *         wait_task_stopped()
>   2279           *           task_stopped_code()
>   2280           * [L]         task_is_traced()         [S] task_clear_jobctl_trapping();
>   2281           */
>   2282          smp_wmb();
>   2283
>   2284          current->ptrace_message = message;
>   2285          current->last_siginfo = info;
>   2286          current->exit_code = exit_code;
>   2287
>   2288          /*
>   2289           * If @why is CLD_STOPPED, we're trapping to participate in a group
>   2290           * stop.  Do the bookkeeping.  Note that if SIGCONT was delievered
>   2291           * across siglock relocks since INTERRUPT was scheduled, PENDING
>   2292           * could be clear now.  We act as if SIGCONT is received after
>   2293           * TASK_TRACED is entered - ignore it.
>   2294           */
>   2295          if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
>   2296                  gstop_done = task_participate_group_stop(current);
>   2297
>   2298          /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
>   2299          task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
>   2300          if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
>   2301                  task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
>   2302
>   2303          /* entering a trap, clear TRAPPING */
>   2304          task_clear_jobctl_trapping(current);
>   2305
>   2306          spin_unlock_irq(&current->sighand->siglock);
>   2307          read_lock(&tasklist_lock);
>   2308          /*
>   2309           * Notify parents of the stop.
>   2310           *
>   2311           * While ptraced, there are two parents - the ptracer and
>   2312           * the real_parent of the group_leader.  The ptracer should
>   2313           * know about every stop while the real parent is only
>   2314           * interested in the completion of group stop.  The states
>   2315           * for the two don't interact with each other.  Notify
>   2316           * separately unless they're gonna be duplicates.
>   2317           */
>   2318          if (current->ptrace)
>   2319                  do_notify_parent_cldstop(current, true, why);
>   2320          if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
>   2321                  do_notify_parent_cldstop(current, false, why);
>   2322
>   2323          /*
>   2324           * If tracer is frozen, it won't ack until it gets unfrozen and if the
>   2325           * tracee is exiting this means its resources do not get freed until
>   2326           * the tracer is thawed. Skip waiting for the tracer. Per ptrace(2)
>   2327           * manual, the tracer cannot assume that the ptrace-stopped tracee
>   2328           * exists, so exiting now should not be an issue.
>   2329           */
>   2330          if (current->ptrace && (exit_code >> 8) == PTRACE_EVENT_EXIT &&
> > 2331              cgroup_task_frozen(current->parent)) {

This patch will be changing based on Oleg's feedback here:
https://lore.kernel.org/all/20240629131247.GA6138@redhat.com/
I'm not yet sure how this issue will be ultimatel fixed (hope I get
some more guidance) but for now Andrew, could you please pull this
patch out?
Thanks!

>   2332                  read_unlock(&tasklist_lock);
>   2333                  goto skip_wait;
>   2334          }
>   2335
>   2336          /*
>   2337           * The previous do_notify_parent_cldstop() invocation woke ptracer.
>   2338           * One a PREEMPTION kernel this can result in preemption requirement
>   2339           * which will be fulfilled after read_unlock() and the ptracer will be
>   2340           * put on the CPU.
>   2341           * The ptracer is in wait_task_inactive(, __TASK_TRACED) waiting for
>   2342           * this task wait in schedule(). If this task gets preempted then it
>   2343           * remains enqueued on the runqueue. The ptracer will observe this and
>   2344           * then sleep for a delay of one HZ tick. In the meantime this task
>   2345           * gets scheduled, enters schedule() and will wait for the ptracer.
>   2346           *
>   2347           * This preemption point is not bad from a correctness point of
>   2348           * view but extends the runtime by one HZ tick time due to the
>   2349           * ptracer's sleep.  The preempt-disable section ensures that there
>   2350           * will be no preemption between unlock and schedule() and so
>   2351           * improving the performance since the ptracer will observe that
>   2352           * the tracee is scheduled out once it gets on the CPU.
>   2353           *
>   2354           * On PREEMPT_RT locking tasklist_lock does not disable preemption.
>   2355           * Therefore the task can be preempted after do_notify_parent_cldstop()
>   2356           * before unlocking tasklist_lock so there is no benefit in doing this.
>   2357           *
>   2358           * In fact disabling preemption is harmful on PREEMPT_RT because
>   2359           * the spinlock_t in cgroup_enter_frozen() must not be acquired
>   2360           * with preemption disabled due to the 'sleeping' spinlock
>   2361           * substitution of RT.
>   2362           */
>   2363          if (!IS_ENABLED(CONFIG_PREEMPT_RT))
>   2364                  preempt_disable();
>   2365          read_unlock(&tasklist_lock);
>   2366          cgroup_enter_frozen();
>   2367          if (!IS_ENABLED(CONFIG_PREEMPT_RT))
>   2368                  preempt_enable_no_resched();
>   2369          schedule();
>   2370          cgroup_leave_frozen(true);
>   2371
>   2372  skip_wait:
>   2373          /*
>   2374           * We are back.  Now reacquire the siglock before touching
>   2375           * last_siginfo, so that we are sure to have synchronized with
>   2376           * any signal-sending on another CPU that wants to examine it.
>   2377           */
>   2378          spin_lock_irq(&current->sighand->siglock);
>   2379          exit_code = current->exit_code;
>   2380          current->last_siginfo = NULL;
>   2381          current->ptrace_message = 0;
>   2382          current->exit_code = 0;
>   2383
>   2384          /* LISTENING can be set only during STOP traps, clear it */
>   2385          current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
>   2386
>   2387          /*
>   2388           * Queued signals ignored us while we were stopped for tracing.
>   2389           * So check for any that we should take before resuming user mode.
>   2390           * This sets TIF_SIGPENDING, but never clears it.
>   2391           */
>   2392          recalc_sigpending_tsk(current);
>   2393          return exit_code;
>   2394  }
>   2395
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki