linux-toradex.git/kernel/signal.c, branch v6.8

kernel/signal.c: simplify force_sig_info_to_task(), kill recalc_sigpending_and_wake()

2023-12-11T01:21:32+00:00

The purpose of recalc_sigpending_and_wake() is not clear, it looks
"obviously unneeded" because we are going to send the signal which can't
be blocked or ignored.

Add the comment to explain why we can't rely on send_signal_locked() and
make this logic more simple/explicit.  recalc_sigpending_and_wake() has no
other users, it can die.

In fact I think we don't even need signal_wake_up(), the target task must
be either current or a TASK_TRACED child, otherwise the usage of siglock
is not safe.  But this needs another change.

Link: https://lkml.kernel.org/r/20231120151649.GA15995@redhat.com
Signed-off-by: Oleg Nesterov 
Cc: Eric Biederman 
Signed-off-by: Andrew Morton

introduce for_other_threads(p, t)

2023-12-11T01:21:25+00:00

Cosmetic, but imho it makes the usage look more clear and simple, the new
helper doesn't require to initialize "t".

After this change while_each_thread() has only 3 users, and it is only
used in the do/while loops.

Link: https://lkml.kernel.org/r/20231030155710.GA9095@redhat.com
Signed-off-by: Oleg Nesterov 
Reviewed-by: Christian Brauner 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31+00:00

Pull non-MM updates from Andrew Morton:
 "As usual, lots of singleton and doubleton patches all over the tree
  and there's little I can say which isn't in the individual changelogs.

  The lengthier patch series are

   - 'kdump: use generic functions to simplify crashkernel reservation
     in arch', from Baoquan He. This is mainly cleanups and
     consolidation of the 'crashkernel=' kernel parameter handling

   - After much discussion, David Laight's 'minmax: Relax type checks in
     min() and max()' is here. Hopefully reduces some typecasting and
     the use of min_t() and max_t()

   - A group of patches from Oleg Nesterov which clean up and slightly
     fix our handling of reads from /proc/PID/task/... and which remove
     task_struct.thread_group"

* tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits)
  scripts/gdb/vmalloc: disable on no-MMU
  scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n
  .mailmap: add address mapping for Tomeu Vizoso
  mailmap: update email address for Claudiu Beznea
  tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions
  .mailmap: map Benjamin Poirier's address
  scripts/gdb: add lx_current support for riscv
  ocfs2: fix a spelling typo in comment
  proc: test ProtectionKey in proc-empty-vm test
  proc: fix proc-empty-vm test with vsyscall
  fs/proc/base.c: remove unneeded semicolon
  do_io_accounting: use sig->stats_lock
  do_io_accounting: use __for_each_thread()
  ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error()
  ocfs2: fix a typo in a comment
  scripts/show_delta: add __main__ judgement before main code
  treewide: mark stuff as __ro_after_init
  fs: ocfs2: check status values
  proc: test /proc/${pid}/statm
  compiler.h: move __is_constexpr() to compiler.h
  ...

Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2023-11-02T01:28:33+00:00

Pull ia64 removal and asm-generic updates from Arnd Bergmann:

 - The ia64 architecture gets its well-earned retirement as planned,
   now that there is one last (mostly) working release that will be
   maintained as an LTS kernel.

 - The architecture specific system call tables are updated for the
   added map_shadow_stack() syscall and to remove references to the
   long-gone sys_lookup_dcookie() syscall.

* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  hexagon: Remove unusable symbols from the ptrace.h uapi
  asm-generic: Fix spelling of architecture
  arch: Reserve map_shadow_stack() syscall number for all architectures
  syscalls: Cleanup references to sys_lookup_dcookie()
  Documentation: Drop or replace remaining mentions of IA64
  lib/raid6: Drop IA64 support
  Documentation: Drop IA64 from feature descriptions
  kernel: Drop IA64 support from sig_fault handlers
  arch: Remove Itanium (IA-64) architecture

kernel/signal: remove unnecessary NULL values from ucounts

2023-10-18T21:43:22+00:00

ucounts is assigned first, so it does not need to initialize the
assignment.

Link: https://lkml.kernel.org/r/20230926022410.4280-1-kunyu@nfschina.com
Signed-off-by: Li kunyu 
Acked-by: Oleg Nesterov 
Signed-off-by: Andrew Morton

signal: complete_signal: use __for_each_thread()

2023-10-04T17:41:57+00:00

do/while_each_thread should be avoided when possible.

Link: https://lkml.kernel.org/r/20230909164537.GA11633@redhat.com
Signed-off-by: Oleg Nesterov 
Cc: Eric W. Biederman 
Signed-off-by: Andrew Morton

__kill_pgrp_info: simplify the calculation of return value

2023-10-04T17:41:56+00:00

No need to calculate/check the "success" variable, we can kill it and update
retval in the main loop unless it is zero.

Link: https://lkml.kernel.org/r/20230823171455.GA12188@redhat.com
Signed-off-by: Oleg Nesterov 
Suggested-by: David Laight 
Cc: Eric W. Biederman 
Signed-off-by: Andrew Morton

signal: Don't disable preemption in ptrace_stop() on PREEMPT_RT

2023-09-19T20:08:29+00:00

On PREEMPT_RT keeping preemption disabled during the invocation of
cgroup_enter_frozen() is a problem because the function acquires
css_set_lock which is a sleeping lock on PREEMPT_RT and must not be
acquired with disabled preemption.

The preempt-disabled section is only for performance optimisation reasons
and can be avoided.

Extend the comment and don't disable preemption before scheduling on
PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: Oleg Nesterov 
Link: https://lore.kernel.org/r/20230803100932.325870-3-bigeasy@linutronix.de

signal: Add a proper comment about preempt_disable() in ptrace_stop()

2023-09-19T20:08:29+00:00

Commit 53da1d9456fe7 ("fix ptrace slowness") added a preempt-disable section
between read_unlock() and the following schedule() invocation without
explaining why it is needed.

Replace the existing contentless comment with a proper explanation to
clarify that it is not needed for correctness but for performance reasons.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: Oleg Nesterov 
Link: https://lore.kernel.org/r/20230803100932.325870-2-bigeasy@linutronix.de

kernel: Drop IA64 support from sig_fault handlers

2023-09-11T08:13:18+00:00

Signed-off-by: Ard Biesheuvel