linux-toradex.git/kernel/debug/kdb/kdb_support.c, branch v5.12-rc8

kdb: kdb_support: Fix debugging information problem

2021-02-04T15:55:04+00:00

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 
Link: https://lore.kernel.org/r/1612440429-6391-1-git-send-email-stephenzhangzsd@gmail.com
Reviewed-by: Douglas Anderson 
[daniel.thompson@linaro.org: Minor typo and line length fixes in the
patch description]
Signed-off-by: Daniel Thompson

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

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

2020-06-17T17:57:41+00:00

Better describe what these functions do.

Suggested-by: Linus Torvalds 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Linus Torvalds

kdb: kdb_support: replace strcpy() by strscpy()

2019-05-02T12:42:01+00:00

The strcpy() function is being deprecated. Replace it by the safer
strscpy() and fix the following Coverity warning:

"You might overrun the 129-character fixed-size string ks_namebuf
by copying name without checking the length."

Addresses-Coverity-ID: 138995 ("Copy into fixed size buffer")
Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Daniel Thompson

kdb: kdb_support: mark expected switch fall-throughs

2018-11-13T20:38:50+00:00

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case, I replaced the code comments with
a proper "fall through" annotation, which is what GCC is expecting
to find.

Signed-off-by: Gustavo A. R. Silva 
Reviewed-by: Daniel Thompson 
Signed-off-by: Daniel Thompson

kdb: Use strscpy with destination buffer size

2018-11-13T20:27:53+00:00

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 
Cc: Jonathan Toppins 
Cc: Jason Wessel 
Cc: Daniel Thompson 
Cc: kgdb-bugreport@lists.sourceforge.net
Reviewed-by: Daniel Thompson 
Signed-off-by: Daniel Thompson

kdb: print real address of pointers instead of hashed addresses

2018-11-13T20:27:37+00:00

Since commit ad67b74d2469 ("printk: hash addresses printed with %p"),
all pointers printed with %p are printed with hashed addresses
instead of real addresses in order to avoid leaking addresses in
dmesg and syslog. But this applies to kdb too, with is unfortunate:

    Entering kdb (current=0x(ptrval), pid 329) due to Keyboard Entry
    kdb> ps
    15 sleeping system daemon (state M) processes suppressed,
    use 'ps A' to see all.
    Task Addr       Pid   Parent [*] cpu State Thread     Command
    0x(ptrval)      329      328  1    0   R  0x(ptrval) *sh

    0x(ptrval)        1        0  0    0   S  0x(ptrval)  init
    0x(ptrval)        3        2  0    0   D  0x(ptrval)  rcu_gp
    0x(ptrval)        4        2  0    0   D  0x(ptrval)  rcu_par_gp
    0x(ptrval)        5        2  0    0   D  0x(ptrval)  kworker/0:0
    0x(ptrval)        6        2  0    0   D  0x(ptrval)  kworker/0:0H
    0x(ptrval)        7        2  0    0   D  0x(ptrval)  kworker/u2:0
    0x(ptrval)        8        2  0    0   D  0x(ptrval)  mm_percpu_wq
    0x(ptrval)       10        2  0    0   D  0x(ptrval)  rcu_preempt

The whole purpose of kdb is to debug, and for debugging real addresses
need to be known. In addition, data displayed by kdb doesn't go into
dmesg.

This patch replaces all %p by %px in kdb in order to display real
addresses.

Fixes: ad67b74d2469 ("printk: hash addresses printed with %p")
Cc: 
Signed-off-by: Christophe Leroy 
Signed-off-by: Daniel Thompson

kdb: use memmove instead of overlapping memcpy

2018-02-05T03:29:53+00:00

gcc discovered that the memcpy() arguments in kdbnearsym() overlap, so
we should really use memmove(), which is defined to handle that correctly:

In function 'memcpy',
    inlined from 'kdbnearsym' at /git/arm-soc/kernel/debug/kdb/kdb_support.c:132:4:
/git/arm-soc/include/linux/string.h:353:9: error: '__builtin_memcpy' accessing 792 bytes at offsets 0 and 8 overlaps 784 bytes at offset 8 [-Werror=restrict]
  return __builtin_memcpy(p, q, size);

Signed-off-by: Arnd Bergmann 
Signed-off-by: Jason Wessel

kdb: remove the second argument of k[un]map_atomic()

2012-03-20T13:48:26+00:00

Signed-off-by: Cong Wang

kdb: Make KDB use the new is_idle_task() API

2011-12-11T18:31:52+00:00

Change from direct comparison of ->pid with zero to is_idle_task().

Signed-off-by: Paul E. McKenney 
Signed-off-by: Paul E. McKenney 
Cc: Jason Wessel 
Reviewed-by: Josh Triplett