kdb: remove usage of static environment buffer

Problem: The set environment variable logic uses a static "heap" like
buffer to store the values of the variables, and they are never freed,
on top of

kdb: remove usage of static environment buffer

Problem: The set environment variable logic uses a static "heap" like
buffer to store the values of the variables, and they are never freed,
on top of that this is redundant since the kernel supplies allocation
facilities which are even used also in this file.

Solution: Remove the weird static buffer logic and use kmalloc instead,
call kfree when overriding an existing variable.

Signed-off-by: Nir Lichtman <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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Revert "kdb: Implement disable_nmi command"

This reverts commit ad394f66fa57ae66014cb74f337e2820bac4c417.

No architectures ever implemented `enable_nmi` since the later patches
in the series adding

Revert "kdb: Implement disable_nmi command"

This reverts commit ad394f66fa57ae66014cb74f337e2820bac4c417.

No architectures ever implemented `enable_nmi` since the later patches
in the series adding it never landed. It's been a long time. Drop it.

NOTE: this is not a clean revert due to changes in the file in the
meantime.

Signed-off-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/20250129082535.2.Ib91bfb95bdcf77591257a84063fdeb5b4dce65b1@changeid
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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kdb: Remove fallback interpretation of arbitrary numbers as hex

Remove logic that enables a fallback of interpreting numbers supplied in KDB CLI
to be interpreted as hex without explicit "0x" prefix

kdb: Remove fallback interpretation of arbitrary numbers as hex

Remove logic that enables a fallback of interpreting numbers supplied in KDB CLI
to be interpreted as hex without explicit "0x" prefix as this can be confusing
for the end users.

Suggested-by: Douglas Anderson <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Signed-off-by: Nir Lichtman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Replace the use of simple_strto with safer kstrto in kdb_main

The simple_str* family of functions perform no error checking in
scenarios where the input value overflows the intended output vari

kdb: Replace the use of simple_strto with safer kstrto in kdb_main

The simple_str* family of functions perform no error checking in
scenarios where the input value overflows the intended output variable.
This results in these functions successfully returning even when the
output does not match the input string.

Or as it was mentioned [1], "...simple_strtol(), simple_strtoll(),
simple_strtoul(), and simple_strtoull() functions explicitly ignore
overflows, which may lead to unexpected results in callers."
Hence, the use of those functions is discouraged.

This patch replaces all uses of the simple_strto* series of functions
with their safer kstrto* alternatives.

Side effects of this patch:
- Every string to long or long long conversion using kstrto* is now
checked for failure.
- kstrto* errors are handled with appropriate `KDB_BADINT` wherever
applicable.
- A good side effect is that we end up saving a few lines of code
since unlike in simple_strto* functions, kstrto functions do not
need an additional "end pointer" variable, and the return values
of the latter can be directly checked in an "if" statement without
the need to define additional `ret` or `err` variables.
This, of course, results in cleaner, yet still easy to understand
code.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull

Signed-off-by: Yuran Pereira <[email protected]>
[nir: addressed review comments by fixing styling, invalid conversion and a missing error return]
Signed-off-by: Nir Lichtman <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Get rid of redundant kdb_curr_task()

Commit cf8e8658100d ("arch: Remove Itanium (IA-64) architecture")
removed the only definition of macro _TIF_MCA_INIT, so kdb_curr_task()
is actually the sam

kdb: Get rid of redundant kdb_curr_task()

Commit cf8e8658100d ("arch: Remove Itanium (IA-64) architecture")
removed the only definition of macro _TIF_MCA_INIT, so kdb_curr_task()
is actually the same as curr_task() now and becomes redundant.

Let's remove the definition of kdb_curr_task() and replace remaining
calls with curr_task().

Signed-off-by: Zheng Zengkai <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Use str_plural() to fix Coccinelle warning

Fixes the following Coccinelle/coccicheck warning reported by
string_choices.cocci:

opportunity for str_plural(days)

Signed-off-by: Thorsten Blum <

kdb: Use str_plural() to fix Coccinelle warning

Fixes the following Coccinelle/coccicheck warning reported by
string_choices.cocci:

opportunity for str_plural(days)

Signed-off-by: Thorsten Blum <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Fix a potential buffer overflow in kdb_local()

When appending "[defcmd]" to 'kdb_prompt_str', the size of the string
already in the buffer should be taken into account.

An option could be to s

kdb: Fix a potential buffer overflow in kdb_local()

When appending "[defcmd]" to 'kdb_prompt_str', the size of the string
already in the buffer should be taken into account.

An option could be to switch from strncat() to strlcat() which does the
correct test to avoid such an overflow.

However, this actually looks as dead code, because 'defcmd_in_progress'
can't be true here.
See a more detailed explanation at [1].

[1]: https://lore.kernel.org/all/CAD=FV=WSh7wKN7Yp-3wWiDgX4E3isQ8uh0LCzTmd1v9Cg9j+nQ@mail.gmail.com/

Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: Christophe JAILLET <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>

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kdb: Corrects comment for kdballocenv

This patch corrects the comment for the kdballocenv function.
The previous comment incorrectly described the function's
parameters and return values.

Signed-of

kdb: Corrects comment for kdballocenv

This patch corrects the comment for the kdballocenv function.
The previous comment incorrectly described the function's
parameters and return values.

Signed-off-by: Yuran Pereira <[email protected]>
Link: https://lore.kernel.org/r/DB3PR10MB6835B383B596133EDECEA98AE8ABA@DB3PR10MB6835.EURPRD10.PROD.OUTLOOK.COM
[[email protected]: fixed whitespace alignment in new lines]
Signed-off-by: Daniel Thompson <[email protected]>

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lockdown: also lock down previous kgdb use

KGDB and KDB allow read and write access to kernel memory, and thus
should be restricted during lockdown. An attacker with access to a
serial port (for ex

lockdown: also lock down previous kgdb use

KGDB and KDB allow read and write access to kernel memory, and thus
should be restricted during lockdown. An attacker with access to a
serial port (for example, via a hypervisor console, which some cloud
vendors provide over the network) could trigger the debugger so it is
important that the debugger respect the lockdown mode when/if it is
triggered.

Fix this by integrating lockdown into kdb's existing permissions
mechanism. Unfortunately kgdb does not have any permissions mechanism
(although it certainly could be added later) so, for now, kgdb is simply
and brutally disabled by immediately exiting the gdb stub without taking
any action.

For lockdowns established early in the boot (e.g. the normal case) then
this should be fine but on systems where kgdb has set breakpoints before
the lockdown is enacted than "bad things" will happen.

CVE: CVE-2022-21499
Co-developed-by: Stephen Brennan <[email protected]>
Signed-off-by: Stephen Brennan <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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module: Move kdb module related code out of main kdb code

No functional change.

This patch migrates the kdb 'lsmod' command support out of main
kdb code into its own file under kernel/module. In ad

module: Move kdb module related code out of main kdb code

No functional change.

This patch migrates the kdb 'lsmod' command support out of main
kdb code into its own file under kernel/module. In addition to
the above, a minor style warning i.e. missing a blank line after
declarations, was resolved too. The new file was added to
MAINTAINERS. Finally we remove linux/module.h as it is entirely
redundant.

Reviewed-by: Daniel Thompson <[email protected]>
Acked-by: Daniel Thompson <[email protected]>
Signed-off-by: Aaron Tomlin <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>

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kdb: Adopt scheduler's task classification

Currently kdb contains some open-coded routines to generate a summary
character for each task. This code currently issues warnings, is
almost certainly bro

kdb: Adopt scheduler's task classification

Currently kdb contains some open-coded routines to generate a summary
character for each task. This code currently issues warnings, is
almost certainly broken and won't make sense to any kernel dev who
has ever used /proc to examine task states.

Fix both the warning and the potential for confusion by adopting the
scheduler's task classification. Whilst doing this we also simplify the
filtering by using mask strings directly (which means we don't have to
guess all the characters the scheduler might give us).

Unfortunately we can't quite match the scheduler classification completely.
We add four extra states: - for idle loops and i, m and s for sleeping
system daemons (which means kthreads in one of the I, M and S states).
These extra states are used to manage the filters for tools to make the
output of ps and bta less noisy.

Note: The Fixes below is the last point the original dubious code was
moved; it was not introduced by that patch. However it gives us
the last point to which this patch can be easily backported.
Happily that should be enough to cover the introduction of
CONFIG_WERROR!

Fixes: 2f064a59a11f ("sched: Change task_struct::state")
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Douglas Anderson <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Rename members of struct kdbtab_t

Remove redundant prefix "cmd_" from name of members in struct kdbtab_t
for better readibility.

Suggested-by: Doug Anderson <[email protected]>
Signed-off-

kdb: Rename members of struct kdbtab_t

Remove redundant prefix "cmd_" from name of members in struct kdbtab_t
for better readibility.

Suggested-by: Doug Anderson <[email protected]>
Signed-off-by: Sumit Garg <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Simplify kdb_defcmd macro logic

Switch to use a linked list instead of dynamic array which makes
allocation of kdb macro and traversing the kdb macro commands list
simpler.

Suggested-by: Danie

kdb: Simplify kdb_defcmd macro logic

Switch to use a linked list instead of dynamic array which makes
allocation of kdb macro and traversing the kdb macro commands list
simpler.

Suggested-by: Daniel Thompson <[email protected]>
Signed-off-by: Sumit Garg <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Get rid of redundant kdb_register_flags()

Commit e4f291b3f7bb ("kdb: Simplify kdb commands registration")
allowed registration of pre-allocated kdb commands with pointer to
struct kdbtab_t. Let

kdb: Get rid of redundant kdb_register_flags()

Commit e4f291b3f7bb ("kdb: Simplify kdb commands registration")
allowed registration of pre-allocated kdb commands with pointer to
struct kdbtab_t. Lets switch other users as well to register pre-
allocated kdb commands via:
- Changing prototype for kdb_register() to pass a pointer to struct
kdbtab_t instead.
- Embed kdbtab_t structure in kdb_macro_t rather than individual params.

With these changes kdb_register_flags() becomes redundant and hence
removed. Also, since we have switched all users to register
pre-allocated commands, "is_dynamic" flag in struct kdbtab_t becomes
redundant and hence removed as well.

Suggested-by: Daniel Thompson <[email protected]>
Signed-off-by: Sumit Garg <[email protected]>
Acked-by: Steven Rostedt (VMware) <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Rename struct defcmd_set to struct kdb_macro

Rename struct defcmd_set to struct kdb_macro as that sounds more
appropriate given its purpose.

Suggested-by: Daniel Thompson <daniel.thompson@lina

kdb: Rename struct defcmd_set to struct kdb_macro

Rename struct defcmd_set to struct kdb_macro as that sounds more
appropriate given its purpose.

Suggested-by: Daniel Thompson <[email protected]>
Signed-off-by: Sumit Garg <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kgdb: Fix spelling mistakes

Fix some spelling mistakes in comments:
initalization ==> initialization
detatch ==> detach
represntation ==> representation
hexidecimal ==> hexadecimal
delimeter ==> del

kgdb: Fix spelling mistakes

Fix some spelling mistakes in comments:
initalization ==> initialization
detatch ==> detach
represntation ==> representation
hexidecimal ==> hexadecimal
delimeter ==> delimiter
architecure ==> architecture

Signed-off-by: Zhen Lei <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Switch to use %ptTs

Use %ptTs instead of open-coded variant to print contents
of time64_t type in human readable form.

Cc: Jason Wessel <[email protected]>
Cc: Daniel Thompson <daniel

kdb: Switch to use %ptTs

Use %ptTs instead of open-coded variant to print contents
of time64_t type in human readable form.

Cc: Jason Wessel <[email protected]>
Cc: Daniel Thompson <[email protected]>
Cc: [email protected]
Signed-off-by: Andy Shevchenko <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Acked-by: Daniel Thompson <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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kdb: Refactor env variables get/set code

Add two new kdb environment access methods as kdb_setenv() and
kdb_printenv() in order to abstract out environment access code
from kdb command functions.

A

kdb: Refactor env variables get/set code

Add two new kdb environment access methods as kdb_setenv() and
kdb_printenv() in order to abstract out environment access code
from kdb command functions.

Also, replace (char *)0 with NULL as an initializer for environment
variables array.

Signed-off-by: Sumit Garg <[email protected]>
Reviewed-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[[email protected]: Replaced (char *)0/NULL initializers with
an array size]
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Simplify kdb commands registration

Simplify kdb commands registration via using linked list instead of
static array for commands storage.

Signed-off-by: Sumit Garg <[email protected]>
Link

kdb: Simplify kdb commands registration

Simplify kdb commands registration via using linked list instead of
static array for commands storage.

Signed-off-by: Sumit Garg <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Douglas Anderson <[email protected]>
[[email protected]: Removed a bunch of .cmd_minline = 0
initializers]
Signed-off-by: Daniel Thompson <[email protected]>

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printk: kmsg_dump: remove _nolock() variants

kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is
no need for _nolock() variants. Remove these functions and switch all
callers of th

printk: kmsg_dump: remove _nolock() variants

kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is
no need for _nolock() variants. Remove these functions and switch all
callers of the _nolock() variants.

The functions without _nolock() were chosen because they are already
exported to kernel modules.

Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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printk: introduce a kmsg_dump iterator

Rather than storing the iterator information in the registered
kmsg_dumper structure, create a separate iterator structure. The
kmsg_dump_iter structure can re

printk: introduce a kmsg_dump iterator

Rather than storing the iterator information in the registered
kmsg_dumper structure, create a separate iterator structure. The
kmsg_dump_iter structure can reside on the stack of the caller, thus
allowing lockless use of the kmsg_dump functions.

Update code that accesses the kernel logs using the kmsg_dumper
structure to use the new kmsg_dump_iter structure. For kmsg_dumpers,
this also means adding a call to kmsg_dump_rewind() to initialize
the iterator.

All this is in preparation for removal of @logbuf_lock.

Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Kees Cook <[email protected]> # pstore
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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printk: kmsg_dumper: remove @active field

All 6 kmsg_dumpers do not benefit from the @active flag:

(provide their own synchronization)
- arch/powerpc/kernel/nvram_64.c
- arch/um/kernel/kmsg_d

printk: kmsg_dumper: remove @active field

All 6 kmsg_dumpers do not benefit from the @active flag:

(provide their own synchronization)
- arch/powerpc/kernel/nvram_64.c
- arch/um/kernel/kmsg_dump.c
- drivers/mtd/mtdoops.c
- fs/pstore/platform.c

(only dump on KMSG_DUMP_PANIC, which does not require
synchronization)
- arch/powerpc/platforms/powernv/opal-kmsg.c
- drivers/hv/vmbus_drv.c

The other 2 kmsg_dump users also do not rely on @active:

(hard-code @active to always be true)
- arch/powerpc/xmon/xmon.c
- kernel/debug/kdb/kdb_main.c

Therefore, @active can be removed.

Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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kdb: Use newer api for tasklist scanning

This kills using the do_each_thread/while_each_thread combo to
iterate all threads and uses for_each_process_thread() instead,
maintaining semantics. while_e

kdb: Use newer api for tasklist scanning

This kills using the do_each_thread/while_each_thread combo to
iterate all threads and uses for_each_process_thread() instead,
maintaining semantics. while_each_thread() is ultimately racy
and deprecated; although in this particular case there is no
concurrency so it doesn't matter. Still lets trivially get rid
of two more users.

Acked-by: Oleg Nesterov <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Thompson <[email protected]>

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maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

Better describe what these functions do.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Chris

maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

Better describe what these functions do.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kdb: Remove the misfeature 'KDBFLAGS'

Currently, 'KDBFLAGS' is an internal variable of kdb, it is combined
by 'KDBDEBUG' and state flags. It will be shown only when 'KDBDEBUG'
is set, and the user c

kdb: Remove the misfeature 'KDBFLAGS'

Currently, 'KDBFLAGS' is an internal variable of kdb, it is combined
by 'KDBDEBUG' and state flags. It will be shown only when 'KDBDEBUG'
is set, and the user can define an environment variable named 'KDBFLAGS'
too. These are puzzling indeed.

After communication with Daniel, it seems that 'KDBFLAGS' is a misfeature.
So let's replace 'KDBFLAGS' with 'KDBDEBUG' to just show the value we
wrote into. After this modification, we can use `md4c1 kdb_flags` instead,
to observe the state flags.

Suggested-by: Daniel Thompson <[email protected]>
Signed-off-by: Wei Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[[email protected]: Make kdb_flags unsigned to avoid arithmetic
right shift]
Signed-off-by: Daniel Thompson <[email protected]>

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