diff options
author | Tejun Heo <tj@kernel.org> | 2013-04-30 18:27:12 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-30 20:04:02 -0400 |
commit | 196779b9b4ce1922afabdc20d0270720603bd46c (patch) | |
tree | 9628ad58fef85b4cc060f434e01fe50a8e0e333c /arch/mips | |
parent | 89e3f23da9c827bfa9806c3d4da83a12c1c8543a (diff) |
dump_stack: consolidate dump_stack() implementations and unify their behaviors
Both dump_stack() and show_stack() are currently implemented by each
architecture. show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack(). On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.
The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().
There's no reason to require archs to implement two separate but mostly
identical functions. It leads to unnecessary subtle information.
This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin. Blackfin's
dump_stack() does something wonky that I don't understand.
Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information. This is used
in blackfin.
This patch brings the following behavior changes.
* On some archs, an extra level in backtrace for show_stack() could be
printed. This is because the top frame was determined in
dump_stack() on those archs while generic dump_stack() can't do that
reliably. It can be compensated by inlining dump_stack() but not
sure whether that'd be necessary.
* Most archs didn't use to print debug info on dump_stack(). They do
now.
An example WARN dump follows.
WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
Hardware name: empty
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
Call Trace:
[<ffffffff81c614dc>] dump_stack+0x19/0x1b
[<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8234a071>] init_workqueues+0x35/0x505
...
v2: CPU number added to the generic debug info as requested by s390
folks and dropped the s390 specific dump_stack(). This loses %ksp
from the debug message which the maintainers think isn't important
enough to keep the s390-specific dump_stack() implementation.
dump_stack_print_info() is moved to kernel/printk.c from
lib/dump_stack.c. Because linkage is per objecct file,
dump_stack_print_info() living in the same lib file as generic
dump_stack() means that archs which implement custom dump_stack()
- at this point, only blackfin - can't use dump_stack_print_info()
as that will bring in the generic version of dump_stack() too. v1
The v1 patch broke build on blackfin due to this issue. The build
breakage was reported by Fengguang Wu.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/mips')
-rw-r--r-- | arch/mips/kernel/traps.c | 13 |
1 files changed, 0 insertions, 13 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index c3abb88170fc..b512b28cf786 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c | |||
@@ -206,19 +206,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) | |||
206 | show_stacktrace(task, ®s); | 206 | show_stacktrace(task, ®s); |
207 | } | 207 | } |
208 | 208 | ||
209 | /* | ||
210 | * The architecture-independent dump_stack generator | ||
211 | */ | ||
212 | void dump_stack(void) | ||
213 | { | ||
214 | struct pt_regs regs; | ||
215 | |||
216 | prepare_frametrace(®s); | ||
217 | show_backtrace(current, ®s); | ||
218 | } | ||
219 | |||
220 | EXPORT_SYMBOL(dump_stack); | ||
221 | |||
222 | static void show_code(unsigned int __user *pc) | 209 | static void show_code(unsigned int __user *pc) |
223 | { | 210 | { |
224 | long i; | 211 | long i; |