linux-toradex.git/kernel/entry, branch v5.10-rc3

entry: Fix the incorrect ordering of lockdep and RCU check

2020-11-04T17:06:14+00:00

When an exception/interrupt hits kernel space and the kernel is not
currently in the idle task then RCU must be watching.

irqentry_enter() validates this via rcu_irq_enter_check_tick(), which in
turn invokes lockdep when taking a lock. But at that point lockdep does not
yet know about the fact that interrupts have been disabled by the CPU,
which triggers a lockdep splat complaining about inconsistent state.

Invoking trace_hardirqs_off() before rcu_irq_enter_check_tick() defeats the
point of rcu_irq_enter_check_tick() because trace_hardirqs_off() uses RCU.

So use the same sequence as for the idle case and tell lockdep about the
irq state change first, invoke the RCU check and then do the lockdep and
tracer update.

Fixes: a5497bab5f72 ("entry: Provide generic interrupt entry/exit code")
Reported-by: Mark Rutland 
Signed-off-by: Thomas Gleixner 
Tested-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87y2jhl19s.fsf@nanos.tec.linutronix.de

Merge tag 'arch-cleanup-2020-10-22' of git://git.kernel.dk/linux-block

2020-10-23T17:06:38+00:00

Pull arch task_work cleanups from Jens Axboe:
 "Two cleanups that don't fit other categories:

   - Finally get the task_work_add() cleanup done properly, so we don't
     have random 0/1/false/true/TWA_SIGNAL confusing use cases. Updates
     all callers, and also fixes up the documentation for
     task_work_add().

   - While working on some TIF related changes for 5.11, this
     TIF_NOTIFY_RESUME cleanup fell out of that. Remove some arch
     duplication for how that is handled"

* tag 'arch-cleanup-2020-10-22' of git://git.kernel.dk/linux-block:
  task_work: cleanup notification modes
  tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume()

Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-18T21:34:50+00:00

Pull RCU changes from Ingo Molnar:

 - Debugging for smp_call_function()

 - RT raw/non-raw lock ordering fixes

 - Strict grace periods for KASAN

 - New smp_call_function() torture test

 - Torture-test updates

 - Documentation updates

 - Miscellaneous fixes

[ This doesn't actually pull the tag - I've dropped the last merge from
  the RCU branch due to questions about the series.   - Linus ]

* tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  smp: Make symbol 'csd_bug_count' static
  kernel/smp: Provide CSD lock timeout diagnostics
  smp: Add source and destination CPUs to __call_single_data
  rcu: Shrink each possible cpu krcp
  rcu/segcblist: Prevent useless GP start if no CBs to accelerate
  torture: Add gdb support
  rcutorture: Allow pointer leaks to test diagnostic code
  rcutorture: Hoist OOM registry up one level
  refperf: Avoid null pointer dereference when buf fails to allocate
  rcutorture: Properly synchronize with OOM notifier
  rcutorture: Properly set rcu_fwds for OOM handling
  torture: Add kvm.sh --help and update help message
  rcutorture: Add CONFIG_PROVE_RCU_LIST to TREE05
  torture: Update initrd documentation
  rcutorture: Replace HTTP links with HTTPS ones
  locktorture: Make function torture_percpu_rwsem_init() static
  torture: document --allcpus argument added to the kvm.sh script
  rcutorture: Output number of elapsed grace periods
  rcutorture: Remove KCSAN stubs
  rcu: Remove unused "cpu" parameter from rcu_report_qs_rdp()
  ...

tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume()

2020-10-17T21:04:36+00:00

All the callers currently do this, clean it up and move the clearing
into tracehook_notify_resume() instead.

Reviewed-by: Oleg Nesterov 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Jens Axboe

Merge tag 'x86_cleanups_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-12T17:51:02+00:00

Pull x86 cleanups from Borislav Petkov:
 "Misc minor cleanups"

* tag 'x86_cleanups_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Fix typo in comments for syscall_enter_from_user_mode()
  x86/resctrl: Fix spelling in user-visible warning messages
  x86/entry/64: Do not include inst.h in calling.h
  x86/mpparse: Remove duplicate io_apic.h include

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

2020-10-09T06:21:56+00:00

Pull v5.10 RCU changes from Paul E. McKenney:

- Debugging for smp_call_function().

- Strict grace periods for KASAN.  The point of this series is to find
  RCU-usage bugs, so the corresponding new RCU_STRICT_GRACE_PERIOD
  Kconfig option depends on both DEBUG_KERNEL and RCU_EXPERT, and is
  further disabled by dfefault.  Finally, the help text includes
  a goodly list of scary caveats.

- New smp_call_function() torture test.

- Torture-test updates.

- Documentation updates.

- Miscellaneous fixes.

Signed-off-by: Ingo Molnar

x86/entry: Fix typo in comments for syscall_enter_from_user_mode()

2020-09-22T16:24:46+00:00

Just to help myself and others with finding the correct function names,
fix a typo for "usermode" vs "user_mode".

Signed-off-by: Kees Cook 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20200919080936.259819-1-keescook@chromium.org

core/entry: Report syscall correctly for trace and audit

2020-09-14T20:49:51+00:00

On v5.8 when doing seccomp syscall rewrites (e.g. getpid into getppid
as seen in the seccomp selftests), trace (and audit) correctly see the
rewritten syscall on entry and exit:

	seccomp_bpf-1307  [000] .... 22974.874393: sys_enter: NR 110 (...
	seccomp_bpf-1307  [000] .N.. 22974.874401: sys_exit: NR 110 = 1304

With mainline we see a mismatched enter and exit (the original syscall
is incorrectly visible on entry):

	seccomp_bpf-1030  [000] ....    21.806766: sys_enter: NR 39 (...
	seccomp_bpf-1030  [000] ....    21.806767: sys_exit: NR 110 = 1027

When ptrace or seccomp change the syscall, this needs to be visible to
trace and audit at that time as well. Update the syscall earlier so they
see the correct value.

Fixes: d88d59b64ca3 ("core/entry: Respect syscall number rewrites")
Reported-by: Michael Ellerman 
Signed-off-by: Kees Cook 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20200912005826.586171-1-keescook@chromium.org

x86/entry: Unbreak 32bit fast syscall

2020-09-04T13:50:14+00:00

Andy reported that the syscall treacing for 32bit fast syscall fails:

# ./tools/testing/selftests/x86/ptrace_syscall_32
...
[RUN] SYSEMU
[FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732)
...
[RUN] SYSCALL
[FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732)
 
The eason is that the conversion to generic entry code moved the retrieval
of the sixth argument (EBP) after the point where the syscall entry work
runs, i.e. ptrace, seccomp, audit...

Unbreak it by providing a split up version of syscall_enter_from_user_mode().

- syscall_enter_from_user_mode_prepare() establishes state and enables
  interrupts

- syscall_enter_from_user_mode_work() runs the entry work

Replace the call to syscall_enter_from_user_mode() in the 32bit fast
syscall C-entry with the split functions and stick the EBP retrieval
between them.

Fixes: 27d6b4d14f5c ("x86/entry: Use generic syscall entry function")
Reported-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/87k0xdjbtt.fsf@nanos.tec.linutronix.de

rcu: Remove unused __rcu_is_watching() function

2020-08-25T01:37:56+00:00

The x86/entry work removed all uses of __rcu_is_watching(), therefore
this commit removes it entirely.

Cc: Andy Lutomirski 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: "H. Peter Anvin" 
Cc: 
Signed-off-by: Paul E. McKenney