Tejun Heo 196779b9b4 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>		2013-04-30 17:04:02 -07:00
..
asm-offsets.c	sanitize tsk_is_polling()	2012-10-01 09:58:13 -04:00
c6x_ksyms.c	C6X: loadable module support	2011-10-06 19:48:13 -04:00
devicetree.c	C6X: devicetree support	2011-10-06 19:47:33 -04:00
dma.c	C6X: memory management and DMA support	2011-10-06 19:47:37 -04:00
entry.S	c6x: switch to generic sigaltstack	2013-02-03 18:15:52 -05:00
head.S	C6X: early boot code	2011-10-06 19:47:28 -04:00
irq.c	C6X: remove dependence on legacy IRQs	2012-07-18 23:49:40 -04:00
Makefile
module.c	C6X: loadable module support	2011-10-06 19:48:13 -04:00
process.c	c6x: Use generic idle loop	2013-04-08 17:39:24 +02:00
ptrace.c	C6X: ptrace support	2011-10-06 19:48:17 -04:00
setup.c	C6X: add basic support for TMS320C6678 SoC	2012-07-18 23:52:31 -04:00
signal.c	C6X: clean up compiler warning	2012-07-18 23:52:54 -04:00
soc.c	arch: Use eth_random_addr	2012-07-16 22:39:25 -07:00
switch_to.S	C6X: process management	2011-10-06 19:47:40 -04:00
sys_c6x.c	C6X: syscalls	2011-10-06 19:47:58 -04:00
time.c	Disintegrate asm/system.h for C6X	2012-03-28 18:30:02 +01:00
traps.c	dump_stack: consolidate dump_stack() implementations and unify their behaviors	2013-04-30 17:04:02 -07:00
vectors.S	C6X: early boot code	2011-10-06 19:47:28 -04:00
vmlinux.lds.S