linux-stable.git/arch/mips/kernel, branch v5.17.2

mips: setup: fix setnocoherentio() boolean setting

2022-02-22T08:35:02+00:00

Correct a typo/pasto: setnocoherentio() should set
dma_default_coherent to false, not true.

Fixes: 14ac09a65e19 ("MIPS: refactor the runtime coherent vs noncoherent DMA indicators")
Signed-off-by: Randy Dunlap 
Cc: Christoph Hellwig 
Cc: Thomas Bogendoerfer 
Cc: linux-mips@vger.kernel.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Thomas Bogendoerfer

MIPS: smp: fill in sibling and core maps earlier

2022-02-16T19:48:10+00:00

After enabling CONFIG_SCHED_CORE (landed during 5.14 cycle),
2-core 2-thread-per-core interAptiv (CPS-driven) started emitting
the following:

[    0.025698] CPU1 revision is: 0001a120 (MIPS interAptiv (multi))
[    0.048183] ------------[ cut here ]------------
[    0.048187] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6025 sched_core_cpu_starting+0x198/0x240
[    0.048220] Modules linked in:
[    0.048233] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc3+ #35 b7b319f24073fd9a3c2aa7ad15fb7993eec0b26f
[    0.048247] Stack : 817f0000 00000004 327804c8 810eb050 00000000 00000004 00000000 c314fdd1
[    0.048278]         830cbd64 819c0000 81800000 817f0000 83070bf4 00000001 830cbd08 00000000
[    0.048307]         00000000 00000000 815fcbc4 00000000 00000000 00000000 00000000 00000000
[    0.048334]         00000000 00000000 00000000 00000000 817f0000 00000000 00000000 817f6f34
[    0.048361]         817f0000 818a3c00 817f0000 00000004 00000000 00000000 4dc33260 0018c933
[    0.048389]         ...
[    0.048396] Call Trace:
[    0.048399] [<8105a7bc>] show_stack+0x3c/0x140
[    0.048424] [<8131c2a0>] dump_stack_lvl+0x60/0x80
[    0.048440] [<8108b5c0>] __warn+0xc0/0xf4
[    0.048454] [<8108b658>] warn_slowpath_fmt+0x64/0x10c
[    0.048467] [<810bd418>] sched_core_cpu_starting+0x198/0x240
[    0.048483] [<810c6514>] sched_cpu_starting+0x14/0x80
[    0.048497] [<8108c0f8>] cpuhp_invoke_callback_range+0x78/0x140
[    0.048510] [<8108d914>] notify_cpu_starting+0x94/0x140
[    0.048523] [<8106593c>] start_secondary+0xbc/0x280
[    0.048539]
[    0.048543] ---[ end trace 0000000000000000 ]---
[    0.048636] Synchronize counters for CPU 1: done.

...for each but CPU 0/boot.
Basic debug printks right before the mentioned line say:

[    0.048170] CPU: 1, smt_mask:

So smt_mask, which is sibling mask obviously, is empty when entering
the function.
This is critical, as sched_core_cpu_starting() calculates
core-scheduling parameters only once per CPU start, and it's crucial
to have all the parameters filled in at that moment (at least it
uses cpu_smt_mask() which in fact is `&cpu_sibling_map[cpu]` on
MIPS).

A bit of debugging led me to that set_cpu_sibling_map() performing
the actual map calculation, was being invocated after
notify_cpu_start(), and exactly the latter function starts CPU HP
callback round (sched_core_cpu_starting() is basically a CPU HP
callback).
While the flow is same on ARM64 (maps after the notifier, although
before calling set_cpu_online()), x86 started calculating sibling
maps earlier than starting the CPU HP callbacks in Linux 4.14 (see
[0] for the reference). Neither me nor my brief tests couldn't find
any potential caveats in calculating the maps right after performing
delay calibration, but the WARN splat is now gone.
The very same debug prints now yield exactly what I expected from
them:

[    0.048433] CPU: 1, smt_mask: 0-1

[0] https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?id=76ce7cfe35ef

Signed-off-by: Alexander Lobakin 
Reviewed-by: Philippe Mathieu-Daudé 
Signed-off-by: Thomas Bogendoerfer

MIPS: Fix build error due to PTR used in more places

2022-01-27T08:04:19+00:00

Use PTR_WD instead of PTR to avoid clashes with other parts.

Signed-off-by: Thomas Bogendoerfer

Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-01-17T03:49:30+00:00

Pull signal/exit/ptrace updates from Eric Biederman:
 "This set of changes deletes some dead code, makes a lot of cleanups
  which hopefully make the code easier to follow, and fixes bugs found
  along the way.

  The end-game which I have not yet reached yet is for fatal signals
  that generate coredumps to be short-circuit deliverable from
  complete_signal, for force_siginfo_to_task not to require changing
  userspace configured signal delivery state, and for the ptrace stops
  to always happen in locations where we can guarantee on all
  architectures that the all of the registers are saved and available on
  the stack.

  Removal of profile_task_ext, profile_munmap, and profile_handoff_task
  are the big successes for dead code removal this round.

  A bunch of small bug fixes are included, as most of the issues
  reported were small enough that they would not affect bisection so I
  simply added the fixes and did not fold the fixes into the changes
  they were fixing.

  There was a bug that broke coredumps piped to systemd-coredump. I
  dropped the change that caused that bug and replaced it entirely with
  something much more restrained. Unfortunately that required some
  rebasing.

  Some successes after this set of changes: There are few enough calls
  to do_exit to audit in a reasonable amount of time. The lifetime of
  struct kthread now matches the lifetime of struct task, and the
  pointer to struct kthread is no longer stored in set_child_tid. The
  flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
  removed. Issues where task->exit_code was examined with
  signal->group_exit_code should been examined were fixed.

  There are several loosely related changes included because I am
  cleaning up and if I don't include them they will probably get lost.

  The original postings of these changes can be found at:
     https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org

  I trimmed back the last set of changes to only the obviously correct
  once. Simply because there was less time for review than I had hoped"

* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
  ptrace/m68k: Stop open coding ptrace_report_syscall
  ptrace: Remove unused regs argument from ptrace_report_syscall
  ptrace: Remove second setting of PT_SEIZED in ptrace_attach
  taskstats: Cleanup the use of task->exit_code
  exit: Use the correct exit_code in /proc//stat
  exit: Fix the exit_code for wait_task_zombie
  exit: Coredumps reach do_group_exit
  exit: Remove profile_handoff_task
  exit: Remove profile_task_exit & profile_munmap
  signal: clean up kernel-doc comments
  signal: Remove the helper signal_group_exit
  signal: Rename group_exit_task group_exec_task
  coredump: Stop setting signal->group_exit_task
  signal: Remove SIGNAL_GROUP_COREDUMP
  signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
  signal: Make coredump handling explicit in complete_signal
  signal: Have prepare_signal detect coredumps using signal->core_state
  signal: Have the oom killer detect coredumps using signal->core_state
  exit: Move force_uaccess back into do_exit
  exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
  ...

Merge branch 'akpm' (patches from Andrew)

2022-01-15T18:37:06+00:00

Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton : (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...

mm/mempolicy: wire up syscall set_mempolicy_home_node

2022-01-15T14:30:30+00:00

Link: https://lkml.kernel.org/r/20211202123810.267175-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V 
Cc: Ben Widawsky 
Cc: Dave Hansen 
Cc: Feng Tang 
Cc: Michal Hocko 
Cc: Andrea Arcangeli 
Cc: Mel Gorman 
Cc: Mike Kravetz 
Cc: Randy Dunlap 
Cc: Vlastimil Babka 
Cc: Andi Kleen 
Cc: Dan Williams 
Cc: Huang Ying 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

MIPS: signal: Return immediately if call fails

2022-01-02T13:16:40+00:00

When debug sigaltstack(), copy_siginfo_to_user() fails first in
setup_rt_frame() if the alternate signal stack is too small, so
it should return immediately if call fails, no need to call the
following functions.

Signed-off-by: Tiezhu Yang 
Signed-off-by: Thomas Bogendoerfer

MIPS: signal: Protect against sigaltstack wraparound

2022-01-02T13:16:29+00:00

If a process uses alternative signal stack by using sigaltstack(),
then that stack overflows and stack wraparound occurs.

Simple Explanation:
The accurate sp order is A,B,C,D,...
But now the sp points to A,B,C and A,B,C again.

This problem can reproduce by the following code:

  $ cat test_sigaltstack.c
  #include 
  #include 
  #include 
  #include 

  volatile int counter = 0;

  void print_sp()
  {
      unsigned long sp;

      __asm__ __volatile__("move %0, $sp" : "=r" (sp));
      printf("sp = 0x%08lx\n", sp);
  }

  void segv_handler()
  {
      int *c = NULL;

      print_sp();
      counter++;
      printf("%d\n", counter);

      if (counter == 23)
          abort();

      *c = 1;	// SEGV
  }

  int main()
  {
      int *c = NULL;
      char *s = malloc(SIGSTKSZ);
      stack_t stack;
      struct sigaction action;

      memset(s, 0, SIGSTKSZ);
      stack.ss_sp = s;
      stack.ss_flags = 0;
      stack.ss_size = SIGSTKSZ;
      if (sigaltstack(&stack, NULL)) {
          printf("Failed to use sigaltstack!\n");
          return -1;
      }

      memset(&action, 0, sizeof(action));
      action.sa_handler = segv_handler;
      action.sa_flags = SA_ONSTACK | SA_NODEFER;
      sigemptyset(&action.sa_mask);
      sigaction(SIGSEGV, &action, NULL);

      *c = 0;	//SEGV

      if (!s)
          free(s);

      return 0;
  }
  $ gcc test_sigaltstack.c -o test_sigaltstack
  $ ./test_sigaltstack
  sp = 0x120015c80
  1
  sp = 0x120015900
  2
  sp = 0x120015580
  3
  sp = 0x120015200
  4
  sp = 0x120014e80
  5
  sp = 0x120014b00
  6
  sp = 0x120014780
  7
  sp = 0x120014400
  8
  sp = 0x120014080
  9
  sp = 0x120013d00
  10
  sp = 0x120015c80
  11               # wraparound occurs! the 11nd output is same as 1st.
  sp = 0x120015900
  12
  sp = 0x120015580
  13
  sp = 0x120015200
  14
  sp = 0x120014e80
  15
  sp = 0x120014b00
  16
  sp = 0x120014780
  17
  sp = 0x120014400
  18
  sp = 0x120014080
  19
  sp = 0x120013d00
  20
  sp = 0x120015c80
  21                # wraparound occurs! the 21nd output is same as 1st.
  sp = 0x120015900
  22
  sp = 0x120015580
  23
  Aborted

With this patch:

  $ ./test_sigaltstack
  sp = 0x120015c80
  1
  sp = 0x120015900
  2
  sp = 0x120015580
  3
  sp = 0x120015200
  4
  sp = 0x120014e80
  5
  sp = 0x120014b00
  6
  sp = 0x120014780
  7
  sp = 0x120014400
  8
  sp = 0x120014080
  9
  Segmentation fault

If we are on the alternate signal stack and would overflow it, don't.
Return an always-bogus address instead so we will die with SIGSEGV.

This patch is similar with commit 83bd01024b1f ("x86: protect against
sigaltstack wraparound").

Signed-off-by: Tiezhu Yang 
Signed-off-by: Thomas Bogendoerfer

exit: Add and use make_task_dead.

2021-12-13T18:04:45+00:00

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman"

MIPS: CPC: Use bitfield helpers

2021-11-29T11:42:57+00:00

Use the FIELD_PREP() helper, instead of open-coding the same operation.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Thomas Bogendoerfer