linux-stable.git/kernel/debug/kdb, branch linux-6.9.y

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

2024-06-16T11:51:09+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()

2024-06-16T11:51:09+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

2024-06-16T11:51:09+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()

2024-06-16T11:51:09+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

2024-06-16T11:51:09+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

kdb: Fix a potential buffer overflow in kdb_local()

2024-01-17T17:19:06+00:00

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 
Reviewed-by: Douglas Anderson

kdb: Corrects comment for kdballocenv

2023-11-06T17:13:55+00:00

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 
Link: https://lore.kernel.org/r/DB3PR10MB6835B383B596133EDECEA98AE8ABA@DB3PR10MB6835.EURPRD10.PROD.OUTLOOK.COM
[daniel.thompson@linaro.org: fixed whitespace alignment in new lines]
Signed-off-by: Daniel Thompson

Merge tag 'printk-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2023-09-04T20:20:19+00:00

Pull printk updates from Petr Mladek:

 - Do not try to get the console lock when it is not need or useful in
   panic()

 - Replace the global console_suspended state by a per-console flag

 - Export symbols needed for dumping the raw printk buffer in panic()

 - Fix documentation of printf formats for integer types

 - Moved Sergey Senozhatsky to the reviewer role

 - Misc cleanups

* tag 'printk-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: export symbols for debug modules
  lib: test_scanf: Add explicit type cast to result initialization in test_number_prefix()
  printk: ringbuffer: Fix truncating buffer size min_t cast
  printk: Rename abandon_console_lock_in_panic() to other_cpu_in_panic()
  printk: Add per-console suspended state
  printk: Consolidate console deferred printing
  printk: Do not take console lock for console_flush_on_panic()
  printk: Keep non-panic-CPUs out of console lock
  printk: Reduce console_unblank() usage in unsafe scenarios
  kdb: Do not assume write() callback available
  docs: printk-formats: Treat char as always unsigned
  docs: printk-formats: Fix hex printing of signed values
  MAINTAINERS: adjust printk/vsprintf entries

kdb: Do not assume write() callback available

2023-07-20T11:06:22+00:00

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

kdb: move kdb_send_sig() declaration to a better header file

2023-07-03T08:27:12+00:00

kdb_send_sig() is defined in the signal code and called from kdb,
but the declaration is part of the kdb internal code.
Move the declaration to the shared header to avoid the warning:

kernel/signal.c:4789:6: error: no previous prototype for 'kdb_send_sig' [-Werror=missing-prototypes]

Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/lkml/20230517125423.930967-1-arnd@kernel.org/
Signed-off-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20230630201206.2396930-1-daniel.thompson@linaro.org