The "kgdb_connected" variable of debug_core just indicates whether or
not kgdbts is connected to the debug_core. It does not completely
prevent a script from trying invoke kgdbts again and possibly crashing
the system (see Call Trace below).
The configured variable in kgtbts can be used instead of
kgdb_connected instead of kgdb_connected. The cleanup_kgdbts() can
also be removed because there is no possible way to build kgdbts as a
kernel module that you could unload with rmmod.
Call Trace:
-----------------------------------------------------------------
root:/$ echo kgdbts=V1S1000 > /sys/module/kgdbts/parameters/kgdbts
kgdb: Unregistered I/O driver kgdbts, debugger disabled.
------------[ cut here ]------------
WARNING: at kernel/debug/debug_core.c:1002
kgdb_unregister_io_module+0xec/0x100()
Hardware name: Moon Creek platform
Modules linked in:
Pid: 664, comm: sh Not tainted 2.6.34.1-WR4.0.0.0_standard #58
Call Trace:
[<c103b1ed>] warn_slowpath_common+0x6d/0xa0
[<c1079fdc>] ? kgdb_unregister_io_module+0xec/0x100
[<c1079fdc>] ? kgdb_unregister_io_module+0xec/0x100
[<c10544e0>] ? param_attr_store+0x0/0x20
[<c103b235>] warn_slowpath_null+0x15/0x20
[<c1079fdc>] kgdb_unregister_io_module+0xec/0x100
[<c124e4ea>] cleanup_kgdbts+0x1a/0x20
[<c124eced>] param_set_kgdbts_var+0x6d/0xb0
[<c124ec80>] ? param_set_kgdbts_var+0x0/0xb0
[<c10544f7>] param_attr_store+0x17/0x20
[<c105457c>] module_attr_store+0x2c/0x40
[<c111fe84>] sysfs_write_file+0x94/0xf0
[<c10d42f6>] vfs_write+0x96/0x130
[<c111fdf0>] ? sysfs_write_file+0x0/0xf0
[<c10d44d6>] sys_write+0x46/0xd0
[<c13bf329>] system_call_done+0x0/0x4
---[ end trace 4eb028c6ee43154c ]---
kgdb: Unregistered I/O driver kgdbts, debugger disabled.
-----------------------------------------------------------------
[jason.wessel@windriver.com: remove cleanup_kgdbts() ]
Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
The kgdb test suite mimics the behavior of gdb. For the sh
architecture the pc must be decremented by 2 for software breakpoint.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Some versions of gcc replace calls to strstr() with single-character
"needle" string parameters by calls to strchr() behind our back.
This causes linking errors if strchr() is defined as an inline function
in <asm/string.h> (e.g. on m68k, which BTW doesn't have kgdb support).
Prevent this by explicitly calling strchr() instead.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Prevent write to put_buf[BUFMAX] in kgdb test suite.
If put_buf_cnt was BUFMAX - 1 at the earlier test,
`\0' is written to put_buf[BUFMAX].
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Whenever CONFIG_DEBUG_RODATA is set in the kernel config many kernel
text sections become read-only, and the use of software breakpoints in
the kgdb tests will cause the kernel to fail to complete the start up.
Until such time that there is an official API for modifying read-only
text sections hardware breakpoints must be used to run the do_fork or
sys_open tests or the tests get skipped.
Also fix the duplicated include reported by:
Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
The single step test is not terribly costly and it should be able to
pass at 1000 loops successfully in under 1 second. A non-kgdb timing
regression was found using this test, but it did not occur frequently
because by default the test was only executed a single time.
This patch changes the default for the single step test to 1000
iterations and allows for individual configuration of the single step
test to further exercise the kgdb subsystem when needed.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Shadowed variable and integer as NULL pointer fixes:
drivers/misc/kgdbts.c:877:6: warning: symbol 'sys_open_test' shadows an earlier one
drivers/misc/kgdbts.c:537:27: originally declared here
drivers/misc/kgdbts.c:378:22: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:386:22: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:468:30: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:472:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:502:30: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:506:30: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:509:30: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:523:20: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:527:20: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:530:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:541:21: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:545:21: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:548:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:559:30: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:563:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:573:16: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:574:19: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:578:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:588:16: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:589:19: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:593:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:602:16: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:604:15: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:925:3: warning: Using plain integer as NULL pointer
drivers/misc/kgdbts.c:938:3: warning: Using plain integer as NULL pointer
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
This patch adds in the ability to compile the kgdb internal test
string into the kernel so as to run the tests at boot without changing
the kernel boot arguments. This patch also changes all the error
paths to invoke WARN_ON(1) which will emit the line number of the file
and dump the kernel stack when an error occurs.
You can disable the tests in a kernel that is built this way
using "kgdbts="
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds regression tests for testing the kgdb core and arch
specific implementation.
The kgdb test suite is designed to be built into the kernel and not as
a module because it uses a number of low level kernel and kgdb
primitives which should not be exported externally.
The kgdb test suite is designed as a KGDB I/O module which
simulates the communications that a debugger would have with kgdb.
The tests are broken up in to a line by line and referenced here as
a "get" which is kgdb requesting input and "put" which is kgdb
sending a response.
The kgdb suite can be invoked from the kernel command line
arguments system or executed dynamically at run time. The test
suite uses the variable "kgdbts" to obtain the information about
which tests to run and to configure the verbosity level. The
following are the various characters you can use with the kgdbts=
line:
When using the "kgdbts=" you only choose one of the following core
test types:
A = Run all the core tests silently
V1 = Run all the core tests with minimal output
V2 = Run all the core tests in debug mode
You can also specify optional tests:
N## = Go to sleep with interrupts of for ## seconds
to test the HW NMI watchdog
F## = Break at do_fork for ## iterations
S## = Break at sys_open for ## iterations
NOTE: that the do_fork and sys_open tests are mutually exclusive.
To invoke the kgdb test suite from boot you use a kernel start
argument as follows:
kgdbts=V1 kgdbwait
Or if you wanted to perform the NMI test for 6 seconds and do_fork
test for 100 forks, you could use:
kgdbts=V1N6F100 kgdbwait
The test suite can also be invoked at run time with:
echo kgdbts=V1N6F100 > /sys/module/kgdbts/parameters/kgdbts
Or as another example:
echo kgdbts=V2 > /sys/module/kgdbts/parameters/kgdbts
When developing a new kgdb arch specific implementation or
using these tests for the purpose of regression testing,
several invocations are required.
1) Boot with the test suite enabled by using the kernel arguments
"kgdbts=V1F100 kgdbwait"
## If kgdb arch specific implementation has NMI use
"kgdbts=V1N6F100
2) After the system boot run the basic test.
echo kgdbts=V1 > /sys/module/kgdbts/parameters/kgdbts
3) Run the concurrency tests. It is best to use n+1
while loops where n is the number of cpus you have
in your system. The example below uses only two
loops.
## This tests break points on sys_open
while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
echo kgdbts=V1S10000 > /sys/module/kgdbts/parameters/kgdbts
fg # and hit control-c
fg # and hit control-c
## This tests break points on do_fork
while [ 1 ] ; do date > /dev/null ; done &
while [ 1 ] ; do date > /dev/null ; done &
echo kgdbts=V1F1000 > /sys/module/kgdbts/parameters/kgdbts
fg # and hit control-c
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
