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196779b9b4
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> |
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| .. | ||
| cpufreq | ||
| .gitignore | ||
| 8250-platform.c | ||
| asm-offsets.c | ||
| binfmt_elfn32.c | ||
| binfmt_elfo32.c | ||
| bmips_vec.S | ||
| branch.c | ||
| cevt-bcm1480.c | ||
| cevt-ds1287.c | ||
| cevt-gt641xx.c | ||
| cevt-r4k.c | ||
| cevt-sb1250.c | ||
| cevt-smtc.c | ||
| cevt-txx9.c | ||
| cpu-bugs64.c | ||
| cpu-probe.c | ||
| crash_dump.c | ||
| crash.c | ||
| csrc-bcm1480.c | ||
| csrc-gic.c | ||
| csrc-ioasic.c | ||
| csrc-powertv.c | ||
| csrc-r4k.c | ||
| csrc-sb1250.c | ||
| early_printk.c | ||
| entry.S | ||
| ftrace.c | ||
| genex.S | ||
| gpio_txx9.c | ||
| head.S | ||
| i8253.c | ||
| i8259.c | ||
| irq_cpu.c | ||
| irq_txx9.c | ||
| irq-gic.c | ||
| irq-gt641xx.c | ||
| irq-msc01.c | ||
| irq-rm7000.c | ||
| irq.c | ||
| jump_label.c | ||
| kgdb.c | ||
| kprobes.c | ||
| linux32.c | ||
| machine_kexec.c | ||
| Makefile | ||
| mcount.S | ||
| mips_ksyms.c | ||
| mips_machine.c | ||
| mips-mt-fpaff.c | ||
| mips-mt.c | ||
| module-rela.c | ||
| module.c | ||
| octeon_switch.S | ||
| perf_event_mipsxx.c | ||
| perf_event.c | ||
| proc.c | ||
| process.c | ||
| prom.c | ||
| ptrace32.c | ||
| ptrace.c | ||
| r4k_fpu.S | ||
| r4k_switch.S | ||
| r2300_fpu.S | ||
| r2300_switch.S | ||
| r6000_fpu.S | ||
| relocate_kernel.S | ||
| reset.c | ||
| rtlx.c | ||
| scall32-o32.S | ||
| scall64-64.S | ||
| scall64-n32.S | ||
| scall64-o32.S | ||
| setup.c | ||
| signal32.c | ||
| signal_n32.c | ||
| signal-common.h | ||
| signal.c | ||
| smp-bmips.c | ||
| smp-cmp.c | ||
| smp-mt.c | ||
| smp-up.c | ||
| smp.c | ||
| smtc-asm.S | ||
| smtc-proc.c | ||
| smtc.c | ||
| spinlock_test.c | ||
| spram.c | ||
| stacktrace.c | ||
| sync-r4k.c | ||
| syscall.c | ||
| time.c | ||
| topology.c | ||
| traps.c | ||
| unaligned.c | ||
| vdso.c | ||
| vmlinux.lds.S | ||
| vpe.c | ||
| watch.c | ||