linux.git/kernel/debug/kdb/kdb_io.c, branch v6.1.168

kdb: Do not assume write() callback available

2025-02-21T12:50:09+00:00

commit 6d3e0d8cc63221dec670d0ee92ac57961581e975 upstream.

It is allowed for consoles to not provide a write() callback. For
example ttynull does this.

Check if a write() callback is available before using it.

Signed-off-by: John Ogness 
Reviewed-by: Petr Mladek 
Reviewed-by: Douglas Anderson 
Reviewed-by: Daniel Thompson 
Acked-by: Daniel Thompson 
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20230717194607.145135-2-john.ogness@linutronix.de
Cc: Brian Norris 
Signed-off-by: Greg Kroah-Hartman

kdb: Use the passed prompt in kdb_position_cursor()

2024-08-03T06:49:47+00:00

[ Upstream commit e2e821095949cde46256034975a90f88626a2a73 ]

The function kdb_position_cursor() takes in a "prompt" parameter but
never uses it. This doesn't _really_ matter since all current callers
of the function pass the same value and it's a global variable, but
it's a bit ugly. Let's clean it up.

Found by code inspection. This patch is expected to functionally be a
no-op.

Fixes: 09b35989421d ("kdb: Use format-strings rather than '\0' injection in kdb_read()")
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20240528071144.1.I0feb49839c6b6f4f2c4bf34764f5e95de3f55a66@changeid
Signed-off-by: Daniel Thompson 
Signed-off-by: Sasha Levin

kdb: address -Wformat-security warnings

2024-08-03T06:49:47+00:00

[ Upstream commit 70867efacf4370b6c7cdfc7a5b11300e9ef7de64 ]

When -Wformat-security is not disabled, using a string pointer
as a format causes a warning:

kernel/debug/kdb/kdb_io.c: In function 'kdb_read':
kernel/debug/kdb/kdb_io.c:365:36: error: format not a string literal and no format arguments [-Werror=format-security]
  365 |                         kdb_printf(kdb_prompt_str);
      |                                    ^~~~~~~~~~~~~~
kernel/debug/kdb/kdb_io.c: In function 'kdb_getstr':
kernel/debug/kdb/kdb_io.c:456:20: error: format not a string literal and no format arguments [-Werror=format-security]
  456 |         kdb_printf(kdb_prompt_str);
      |                    ^~~~~~~~~~~~~~

Use an explcit "%s" format instead.

Signed-off-by: Arnd Bergmann 
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Reviewed-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20240528121154.3662553-1-arnd@kernel.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Sasha Levin

kdb: Use format-specifiers rather than memset() for padding in kdb_read()

2024-06-16T11:41:40+00:00

commit c9b51ddb66b1d96e4d364c088da0f1dfb004c574 upstream.

Currently when the current line should be removed from the display
kdb_read() uses memset() to fill a temporary buffer with spaces.
The problem is not that this could be trivially implemented using a
format string rather than open coding it. The real problem is that
it is possible, on systems with a long kdb_prompt_str, to write past
the end of the tmpbuffer.

Happily, as mentioned above, this can be trivially implemented using a
format string. Make it so!

Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson 
Tested-by: Justin Stitt 
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-5-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

kdb: Merge identical case statements in kdb_read()

2024-06-16T11:41:40+00:00

commit 6244917f377bf64719551b58592a02a0336a7439 upstream.

The code that handles case 14 (down) and case 16 (up) has been copy and
pasted despite being byte-for-byte identical. Combine them.

Cc: stable@vger.kernel.org # Not a bug fix but it is needed for later bug fixes
Reviewed-by: Douglas Anderson 
Tested-by: Justin Stitt 
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-4-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

kdb: Fix console handling when editing and tab-completing commands

2024-06-16T11:41:39+00:00

commit db2f9c7dc29114f531df4a425d0867d01e1f1e28 upstream.

Currently, if the cursor position is not at the end of the command buffer
and the user uses the Tab-complete functions, then the console does not
leave the cursor in the correct position.

For example consider the following buffer with the cursor positioned
at the ^:

md kdb_pro 10
          ^

Pressing tab should result in:

md kdb_prompt_str 10
                 ^

However this does not happen. Instead the cursor is placed at the end
(after then 10) and further cursor movement redraws incorrectly. The
same problem exists when we double-Tab but in a different part of the
code.

Fix this by sending a carriage return and then redisplaying the text to
the left of the cursor.

Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson 
Tested-by: Justin Stitt 
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-3-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

kdb: Use format-strings rather than '\0' injection in kdb_read()

2024-06-16T11:41:39+00:00

commit 09b35989421dfd5573f0b4683c7700a7483c71f9 upstream.

Currently when kdb_read() needs to reposition the cursor it uses copy and
paste code that works by injecting an '\0' at the cursor position before
delivering a carriage-return and reprinting the line (which stops at the
'\0').

Tidy up the code by hoisting the copy and paste code into an appropriately
named function. Additionally let's replace the '\0' injection with a
proper field width parameter so that the string will be abridged during
formatting instead.

Cc: stable@vger.kernel.org # Not a bug fix but it is needed for later bug fixes
Tested-by: Justin Stitt 
Reviewed-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-2-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

kdb: Fix buffer overflow during tab-complete

2024-06-16T11:41:39+00:00

commit e9730744bf3af04cda23799029342aa3cddbc454 upstream.

Currently, when the user attempts symbol completion with the Tab key, kdb
will use strncpy() to insert the completed symbol into the command buffer.
Unfortunately it passes the size of the source buffer rather than the
destination to strncpy() with predictably horrible results. Most obviously
if the command buffer is already full but cp, the cursor position, is in
the middle of the buffer, then we will write past the end of the supplied
buffer.

Fix this by replacing the dubious strncpy() calls with memmove()/memcpy()
calls plus explicit boundary checks to make sure we have enough space
before we start moving characters around.

Reported-by: Justin Stitt 
Closes: https://lore.kernel.org/all/CAFhGd8qESuuifuHsNjFPR-Va3P80bxrw+LqvC8deA8GziUJLpw@mail.gmail.com/
Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson 
Reviewed-by: Justin Stitt 
Tested-by: Justin Stitt 
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-1-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

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

2022-04-05T15:43:04+00:00

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 
Acked-by: Daniel Thompson 
Signed-off-by: Aaron Tomlin 
Signed-off-by: Luis Chamberlain

kdb: Fix pager search for multi-line strings

2020-10-01T13:44:08+00:00

Currently using forward search doesn't handle multi-line strings correctly.
The search routine replaces line breaks with \0 during the search and, for
regular searches ("help | grep Common\n"), there is code after the line
has been discarded or printed to replace the break character.

However during a pager search ("help\n" followed by "/Common\n") when the
string is matched we will immediately return to normal output and the code
that should restore the \n becomes unreachable. Fix this by restoring the
replaced character when we disable the search mode and update the comment
accordingly.

Fixes: fb6daa7520f9d ("kdb: Provide forward search at more prompt")
Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson 
Signed-off-by: Daniel Thompson