linux.git/kernel/printk/sysctl.c, branch v6.18.21

treewide: const qualify ctl_tables where applicable

2025-01-28T12:48:37+00:00

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.

Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.

Created this by running an spatch followed by a sed command:
Spatch:
    virtual patch

    @
    depends on !(file in "net")
    disable optional_qualifier
    @

    identifier table_name != {
      watchdog_hardlockup_sysctl,
      iwcm_ctl_table,
      ucma_ctl_table,
      memory_allocation_profiling_sysctls,
      loadpin_sysctl_table
    };
    @@

    + const
    struct ctl_table table_name [] = { ... };

sed:
    sed --in-place \
      -e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
      kernel/utsname_sysctl.c

Reviewed-by: Song Liu 
Acked-by: Steven Rostedt (Google)  # for kernel/trace/
Reviewed-by: Martin K. Petersen  # SCSI
Reviewed-by: Darrick J. Wong  # xfs
Acked-by: Jani Nikula 
Acked-by: Corey Minyard 
Acked-by: Wei Liu 
Acked-by: Thomas Gleixner 
Reviewed-by: Bill O'Donnell 
Acked-by: Baoquan He 
Acked-by: Ashutosh Dixit 
Acked-by: Anna Schumaker 
Signed-off-by: Joel Granados

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29+00:00

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh 
Signed-off-by: Thomas Weißschuh 
Co-developed-by: Joel Granados 
Signed-off-by: Joel Granados

printk: Remove the now superfluous sentinel elements from ctl_table array

2024-04-24T07:43:54+00:00

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

rm sentinel element from printk_sysctls

Reviewed-by: Petr Mladek 
Signed-off-by: Joel Granados

printk: Fix incorrect __user type in proc_dointvec_minmax_sysadmin()

2022-02-03T19:27:38+00:00

The move of proc_dointvec_minmax_sysadmin() from kernel/sysctl.c to
kernel/printk/sysctl.c introduced an incorrect __user attribute to the
buffer argument.  I spotted this change in [1] as well as the kernel
test robot.  Revert this change to please sparse:

  kernel/printk/sysctl.c:20:51: warning: incorrect type in argument 3 (different address spaces)
  kernel/printk/sysctl.c:20:51:    expected void *
  kernel/printk/sysctl.c:20:51:    got void [noderef] __user *buffer

Fixes: faaa357a55e0 ("printk: move printk sysctl to printk/sysctl.c")
Link: https://lore.kernel.org/r/20220104155024.48023-2-mic@digikod.net [1]
Reported-by: kernel test robot 
Cc: Andrew Morton 
Cc: John Ogness 
Cc: Luis Chamberlain 
Cc: Petr Mladek 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Xiaoming Ni 
Signed-off-by: Mickaël Salaün 
Link: https://lore.kernel.org/r/20220203145029.272640-1-mic@digikod.net
Signed-off-by: Linus Torvalds

printk: move printk sysctl to printk/sysctl.c

2022-01-22T06:33:35+00:00

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move printk sysctl from kernel/sysctl.c to kernel/printk/sysctl.c.
Use register_sysctl() to register the sysctl interface.

[mcgrof@kernel.org: fixed compile issues when PRINTK is not set, commit log update]

Link: https://lkml.kernel.org/r/20211124231435.1445213-6-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni 
Signed-off-by: Luis Chamberlain 
Cc: Al Viro 
Cc: Amir Goldstein 
Cc: Andy Shevchenko 
Cc: Antti Palosaari 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Benjamin LaHaise 
Cc: Clemens Ladisch 
Cc: David Airlie 
Cc: Douglas Gilbert 
Cc: Eric Biederman 
Cc: Greg Kroah-Hartman 
Cc: Iurii Zaikin 
Cc: James E.J. Bottomley 
Cc: Jani Nikula 
Cc: Jani Nikula 
Cc: Jan Kara 
Cc: Joel Becker 
Cc: John Ogness 
Cc: Joonas Lahtinen 
Cc: Joseph Qi 
Cc: Julia Lawall 
Cc: Kees Cook 
Cc: Lukas Middendorf 
Cc: Mark Fasheh 
Cc: Martin K. Petersen 
Cc: Paul Turner 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Phillip Potter 
Cc: Qing Wang 
Cc: "Rafael J. Wysocki" 
Cc: Rodrigo Vivi 
Cc: Sebastian Reichel 
Cc: Sergey Senozhatsky 
Cc: Stephen Kitt 
Cc: Steven Rostedt (VMware) 
Cc: Suren Baghdasaryan 
Cc: Tetsuo Handa 
Cc: "Theodore Ts'o" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds