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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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| .. | ||
| .gitignore | ||
| apc.c | ||
| asm-offsets.c | ||
| audit.c | ||
| auxio_32.c | ||
| auxio_64.c | ||
| btext.c | ||
| central.c | ||
| cherrs.S | ||
| chmc.c | ||
| compat_audit.c | ||
| cpu.c | ||
| cpumap.c | ||
| cpumap.h | ||
| devices.c | ||
| dma.c | ||
| ds.c | ||
| dtlb_miss.S | ||
| dtlb_prot.S | ||
| ebus.c | ||
| entry.h | ||
| entry.S | ||
| etrap_32.S | ||
| etrap_64.S | ||
| fpu_traps.S | ||
| ftrace.c | ||
| getsetcc.S | ||
| head_32.S | ||
| head_64.S | ||
| helpers.S | ||
| hvapi.c | ||
| hvcalls.S | ||
| hvtramp.S | ||
| idprom.c | ||
| iommu.c | ||
| iommu_common.h | ||
| ioport.c | ||
| irq.h | ||
| irq_32.c | ||
| irq_64.c | ||
| itlb_miss.S | ||
| ivec.S | ||
| jump_label.c | ||
| kernel.h | ||
| kgdb_32.c | ||
| kgdb_64.c | ||
| kprobes.c | ||
| kstack.h | ||
| ktlb.S | ||
| ldc.c | ||
| led.c | ||
| leon_kernel.c | ||
| leon_pci.c | ||
| leon_pci_grpci2.c | ||
| leon_pmc.c | ||
| leon_smp.c | ||
| Makefile | ||
| mdesc.c | ||
| misctrap.S | ||
| module.c | ||
| nmi.c | ||
| of_device_32.c | ||
| of_device_64.c | ||
| of_device_common.c | ||
| of_device_common.h | ||
| pci.c | ||
| pci_common.c | ||
| pci_fire.c | ||
| pci_impl.h | ||
| pci_msi.c | ||
| pci_psycho.c | ||
| pci_sabre.c | ||
| pci_schizo.c | ||
| pci_sun4v.c | ||
| pci_sun4v.h | ||
| pci_sun4v_asm.S | ||
| pcic.c | ||
| pcr.c | ||
| perf_event.c | ||
| pmc.c | ||
| power.c | ||
| process_32.c | ||
| process_64.c | ||
| prom.h | ||
| prom_32.c | ||
| prom_64.c | ||
| prom_common.c | ||
| prom_irqtrans.c | ||
| psycho_common.c | ||
| psycho_common.h | ||
| ptrace_32.c | ||
| ptrace_64.c | ||
| reboot.c | ||
| rtrap_32.S | ||
| rtrap_64.S | ||
| sbus.c | ||
| setup_32.c | ||
| setup_64.c | ||
| signal32.c | ||
| signal_32.c | ||
| signal_64.c | ||
| sigutil.h | ||
| sigutil_32.c | ||
| sigutil_64.c | ||
| smp_32.c | ||
| smp_64.c | ||
| sparc_ksyms_32.c | ||
| sparc_ksyms_64.c | ||
| spiterrs.S | ||
| sstate.c | ||
| stacktrace.c | ||
| starfire.c | ||
| sun4d_irq.c | ||
| sun4d_smp.c | ||
| sun4m_irq.c | ||
| sun4m_smp.c | ||
| sun4v_ivec.S | ||
| sun4v_tlb_miss.S | ||
| sys32.S | ||
| sys_sparc32.c | ||
| sys_sparc_32.c | ||
| sys_sparc_64.c | ||
| syscalls.S | ||
| sysfs.c | ||
| systbls.h | ||
| systbls_32.S | ||
| systbls_64.S | ||
| tadpole.c | ||
| time_32.c | ||
| time_64.c | ||
| trampoline_32.S | ||
| trampoline_64.S | ||
| traps_32.c | ||
| traps_64.c | ||
| tsb.S | ||
| ttable_32.S | ||
| ttable_64.S | ||
| una_asm_32.S | ||
| una_asm_64.S | ||
| unaligned_32.c | ||
| unaligned_64.c | ||
| us2e_cpufreq.c | ||
| us3_cpufreq.c | ||
| utrap.S | ||
| vio.c | ||
| viohs.c | ||
| visemul.c | ||
| vmlinux.lds.S | ||
| windows.c | ||
| winfixup.S | ||
| wof.S | ||
| wuf.S | ||