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: move kdb_send_sig() declaration to a better header file

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 declarat

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

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 <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Daniel Thompson <[email protected]>
Link: https://lore.kernel.org/r/[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: 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: Get rid of custom debug heap allocator

Currently the only user for debug heap is kdbnearsym() which can be
modified to rather use statically allocated buffer for symbol name as
per it's current

kdb: Get rid of custom debug heap allocator

Currently the only user for debug heap is kdbnearsym() which can be
modified to rather use statically allocated buffer for symbol name as
per it's current usage. So do that and hence remove custom debug heap
allocator.

Note that this change puts a restriction on kdbnearsym() callers to
carefully use shared namebuf such that a caller should consume the symbol
returned immediately prior to another call to fetch a different symbol.

Also, this change uses standard KSYM_NAME_LEN macro for namebuf
allocation instead of local variable: knt1_size which should avoid any
conflicts caused by changes to KSYM_NAME_LEN macro value.

This change has been tested using kgdbtest on arm64 which doesn't show
any regressions.

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: 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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kdb: Remove redundant function definitions/prototypes

Cleanup kdb code to get rid of unused function definitions/prototypes.

Signed-off-by: Sumit Garg <[email protected]>
Link: https://lore.ker

kdb: Remove redundant function definitions/prototypes

Cleanup kdb code to get rid of unused function definitions/prototypes.

Signed-off-by: Sumit Garg <[email protected]>
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: Make memory allocations more robust

Currently kdb uses in_interrupt() to determine whether its library
code has been called from the kgdb trap handler or from a saner calling
context such as dr

kdb: Make memory allocations more robust

Currently kdb uses in_interrupt() to determine whether its library
code has been called from the kgdb trap handler or from a saner calling
context such as driver init. This approach is broken because
in_interrupt() alone isn't able to determine kgdb trap handler entry from
normal task context. This can happen during normal use of basic features
such as breakpoints and can also be trivially reproduced using:
echo g > /proc/sysrq-trigger

We can improve this by adding check for in_dbg_master() instead which
explicitly determines if we are running in debugger context.

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

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kdb: kdb_support: Fix debugging information problem

There are several common patterns.

0:
kdb_printf("...",...);

which is the normal one.

1:
kdb_printf("%s: "...,__func__,...)

We

kdb: kdb_support: Fix debugging information problem

There are several common patterns.

0:
kdb_printf("...",...);

which is the normal one.

1:
kdb_printf("%s: "...,__func__,...)

We could improve '1' to this :

#define kdb_func_printf(format, args...) \
kdb_printf("%s: " format, __func__, ## args)

2:
if(KDB_DEBUG(AR))
kdb_printf("%s "...,__func__,...);

We could improve '2' to this :
#define kdb_dbg_printf(mask, format, args...) \
do { \
if (KDB_DEBUG(mask)) \
kdb_func_printf(format, ## args); \
} while (0)

In addition, we changed the format code of size_t to %zu.

Signed-off-by: Stephen Zhang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Douglas Anderson <[email protected]>
[[email protected]: Minor typo and line length fixes in the
patch description]
Signed-off-by: Daniel Thompson <[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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kdb: Gid rid of implicit setting of the current task / regs

Some (but not all?) of the kdb backtrace paths would cause the
kdb_current_task and kdb_current_regs to remain changed. As discussed
in a

kdb: Gid rid of implicit setting of the current task / regs

Some (but not all?) of the kdb backtrace paths would cause the
kdb_current_task and kdb_current_regs to remain changed. As discussed
in a review of a previous patch [1], this doesn't seem intuitive, so
let's fix that.

...but, it turns out that there's actually no longer any reason to set
the current task / current regs while backtracing anymore anyway. As
of commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs
that aren't the master") if we're backtracing on a task running on a
CPU we ask that CPU to do the backtrace itself. Linux can do that
without anything fancy. If we're doing backtrace on a sleeping task
we can also do that fine without updating globals. So this patch
mostly just turns into deleting a bunch of code.

[1] https://lore.kernel.org/r/[email protected]

Signed-off-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/20191109111624.4.Ibc3d982bbeb9e46872d43973ba808cd4c79537c7@changeid
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: kdb_current_regs should be private

As of the patch ("MIPS: kdb: Remove old workaround for backtracing on
other CPUs") there is no reason for kdb_current_regs to be in the
public "kdb.h". Let's

kdb: kdb_current_regs should be private

As of the patch ("MIPS: kdb: Remove old workaround for backtracing on
other CPUs") there is no reason for kdb_current_regs to be in the
public "kdb.h". Let's move it next to kdb_current_task.

Signed-off-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/20191109111623.2.Iadbfb484e90b557cc4b5ac9890bfca732cd99d77@changeid
Signed-off-by: Daniel Thompson <[email protected]>

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kdb: Remove special case logic from kdb_read()

kdb_read() contains special case logic to force it exit after reading
a single character. We can remove all the special case logic by directly
calling

kdb: Remove special case logic from kdb_read()

kdb_read() contains special case logic to force it exit after reading
a single character. We can remove all the special case logic by directly
calling the function to read a single character instead. This also
allows us to tidy up the function prototype which, because it now matches
getchar(), we can also rename in order to make its role clearer.

This does involve some extra code to handle btaprompt properly but we
don't mind the new lines of code here because the old code had some
interesting problems (bad newline handling, treating unexpected
characters like <cr>).

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

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kdb: Use strscpy with destination buffer size

gcc 8.1.0 warns with:

kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’:
kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ spec

kdb: Use strscpy with destination buffer size

gcc 8.1.0 warns with:

kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’:
kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
strncpy(prefix_name, name, strlen(name)+1);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/debug/kdb/kdb_support.c:239:31: note: length computed here

Use strscpy() with the destination buffer size, and use ellipses when
displaying truncated symbols.

v2: Use strscpy()

Signed-off-by: Prarit Bhargava <[email protected]>
Cc: Jonathan Toppins <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: Daniel Thompson <[email protected]>
Cc: [email protected]
Reviewed-by: Daniel Thompson <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>

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signal: Simplify and fix kdb_send_sig

- Rename from kdb_send_sig_info to kdb_send_sig
As there is no meaningful siginfo sent

- Use SEND_SIG_PRIV instead of generating a siginfo for a kdb
signal

signal: Simplify and fix kdb_send_sig

- Rename from kdb_send_sig_info to kdb_send_sig
As there is no meaningful siginfo sent

- Use SEND_SIG_PRIV instead of generating a siginfo for a kdb
signal. The generated siginfo had a bogus rationale and was
not correct in the face of pid namespaces. SEND_SIG_PRIV
is simpler and actually correct.

- As the code grabs siglock just send the signal with siglock
held instead of dropping siglock and attempting to grab it again.

- Move the sig_valid test into kdb_kill where it can generate
a good error message.

Signed-off-by: Eric W. Biederman <[email protected]>

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kdb: properly synchronize vkdb_printf() calls with other CPUs

kdb_printf_lock does not prevent other CPUs from entering the critical
section because it is ignored when KDB_STATE_PRINTF_LOCK is set.

kdb: properly synchronize vkdb_printf() calls with other CPUs

kdb_printf_lock does not prevent other CPUs from entering the critical
section because it is ignored when KDB_STATE_PRINTF_LOCK is set.

The problematic situation might look like:

CPU0 CPU1

vkdb_printf()
if (!KDB_STATE(PRINTF_LOCK))
KDB_STATE_SET(PRINTF_LOCK);
spin_lock_irqsave(&kdb_printf_lock, flags);

vkdb_printf()
if (!KDB_STATE(PRINTF_LOCK))

BANG: The PRINTF_LOCK state is set and CPU1 is entering the critical
section without spinning on the lock.

The problem is that the code tries to implement locking using two state
variables that are not handled atomically. Well, we need a custom
locking because we want to allow reentering the critical section on the
very same CPU.

Let's use solution from Petr Zijlstra that was proposed for a similar
scenario, see
https://lkml.kernel.org/r/[email protected]

This patch uses the same trick with cmpxchg(). The only difference is
that we want to handle only recursion from the same context and
therefore we disable interrupts.

In addition, KDB_STATE_PRINTF_LOCK is removed. In fact, we are not able
to set it a non-racy way.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kdb: Const qualifier for kdb_getstr's prompt argument

All current callers of kdb_getstr() can pass constant pointers via the
prompt argument. This patch adds a const qualification to make explicit
t

kdb: Const qualifier for kdb_getstr's prompt argument

All current callers of kdb_getstr() can pass constant pointers via the
prompt argument. This patch adds a const qualification to make explicit
the fact that this is safe.

Signed-off-by: Daniel Thompson <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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kdb: Provide forward search at more prompt

Currently kdb allows the output of comamnds to be filtered using the
| grep feature. This is useful but does not permit the output emitted
shortly after a

kdb: Provide forward search at more prompt

Currently kdb allows the output of comamnds to be filtered using the
| grep feature. This is useful but does not permit the output emitted
shortly after a string match to be examined without wading through the
entire unfiltered output of the command. Such a feature is particularly
useful to navigate function traces because these traces often have a
useful trigger string *before* the point of interest.

This patch reuses the existing filtering logic to introduce a simple
forward search to kdb that can be triggered from the more prompt.

Signed-off-by: Daniel Thompson <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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kdb: Rename kdb_repeat_t to kdb_cmdflags_t, cmd_repeat to cmd_flags

We're about to add more options for command behaviour, so let's expand
the meaning of kdb_repeat_t.

So far we just do various ren

kdb: Rename kdb_repeat_t to kdb_cmdflags_t, cmd_repeat to cmd_flags

We're about to add more options for command behaviour, so let's expand
the meaning of kdb_repeat_t.

So far we just do various renames, there should be no functional changes.

Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>
Cc: Jason Wessel <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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kdb: Remove currently unused kdbtab_t->cmd_flags

The struct member is never used in the code, so we can remove it.

We will introduce real flags soon by renaming cmd_repeat to cmd_flags.

Signed-off

kdb: Remove currently unused kdbtab_t->cmd_flags

The struct member is never used in the code, so we can remove it.

We will introduce real flags soon by renaming cmd_repeat to cmd_flags.

Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Daniel Thompson <[email protected]>
Cc: Jason Wessel <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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kdb: Remove unhandled ssb command

The 'ssb' command can only be handled when we have a disassembler, to check for
branches, so remove the 'ssb' command for now.

Signed-off-by: Vincent Stehlé <vince

kdb: Remove unhandled ssb command

The 'ssb' command can only be handled when we have a disassembler, to check for
branches, so remove the 'ssb' command for now.

Signed-off-by: Vincent Stehlé <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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printk: Remove kdb_syslog_data

The function is no longer needed, so remove it.

Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]

printk: Remove kdb_syslog_data

The function is no longer needed, so remove it.

Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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KDB: Fix usability issues relating to the 'enter' key.

This fixes the following problems:
1) Typematic-repeat of 'enter' gives warning message
and leaks make/break if KDB exits. Repeats
look s

KDB: Fix usability issues relating to the 'enter' key.

This fixes the following problems:
1) Typematic-repeat of 'enter' gives warning message
and leaks make/break if KDB exits. Repeats
look something like 0x1c 0x1c .... 0x9c
2) Use of 'keypad enter' gives warning message and
leaks the ENTER break/make code out if KDB exits.
KP ENTER repeats look someting like 0xe0 0x1c
0xe0 0x1c ... 0xe0 0x9c.
3) Lag on the order of seconds between "break" and "make" when
expecting the enter "break" code. Seen under virtualized
environments such as VMware ESX.

The existing special enter handler tries to glob the enter break code,
but this fails if the other (KP) enter was used, or if there was a key
repeat. It also fails if you mashed some keys along with enter, and
you ended up with a non-enter make or non-enter break code coming
after the enter make code. So first, we modify the handler to handle
these cases. But performing these actions on every enter is annoying
since now you can't hold ENTER down to scroll <more>d messages in
KDB. Since this special behaviour is only necessary to handle the
exiting KDB ('g' + ENTER) without leaking scancodes to the OS. This
cleanup needs to get executed anytime the kdb_main loop exits.

Tested on QEMU. Set a bp on atkbd.c to verify no scan code was leaked.

Cc: Andrei Warkentin <[email protected]>
[[email protected]: move cleanup calls to kdb_main.c]
Signed-off-by: Andrei Warkentin <[email protected]>
Signed-off-by: Jason Wessel <[email protected]>

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