lwn.git/arch/s390/kernel/dumpstack.c, branch docs-5.10-2

kernel: rename show_stack_loglvl() => show_stack()

2020-06-09T16:39:13+00:00

Now the last users of show_stack() got converted to use an explicit log level, show_stack_loglvl() can drop it's redundant suffix and become once again well known show_stack(). Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com Signed-off-by: Linus Torvalds

s390: add show_stack_loglvl()

2020-06-09T16:39:11+00:00

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Introduce show_stack_loglvl(), that eventually will substitute show_stack(). [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Cc: Christian Borntraeger Cc: Heiko Carstens Cc: Vasily Gorbik Link: http://lkml.kernel.org/r/20200418201944.482088-29-dima@arista.com Signed-off-by: Linus Torvalds

sched/rt, s390: Use CONFIG_PREEMPTION

2019-12-08T13:37:35+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the preemption and entry code over to use CONFIG_PREEMPTION. Add PREEMPT_RT output to die(). [bigeasy: +Kconfig, dumpstack.c] Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Christian Borntraeger Cc: Heiko Carstens Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Vasily Gorbik Cc: linux-s390@vger.kernel.org Link: https://lore.kernel.org/r/20191015191821.11479-18-bigeasy@linutronix.de Signed-off-by: Ingo Molnar

s390/unwind: add stack pointer alignment sanity checks

2019-11-30T09:52:48+00:00

ABI requires SP to be aligned 8 bytes, report unwinding error otherwise. Link: https://lkml.kernel.org/r/20191106095601.29986-5-mbenes@suse.cz Reviewed-by: Heiko Carstens Tested-by: Miroslav Benes Signed-off-by: Miroslav Benes Signed-off-by: Vasily Gorbik

s390/test_unwind: print verbose unwinding results

2019-11-30T09:52:48+00:00

Add stack name, sp and reliable information into test unwinding results. Also consider ip outside of kernel text as failure if the state is reported reliable. Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/unwind: unify task is current checks

2019-11-30T09:52:45+00:00

Avoid mixture of task == NULL and task == current meaning the same thing and simply always initialize task with current in unwind_start. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/unwind: remove stack recursion warning

2019-08-06T11:58:35+00:00

Remove pointless stack recursion on stack type ... warning, which only confuses people. There is no way to make backchain unwinder 100% reliable. When a task is interrupted in-between stack frame allocation and backchain write instructions new stack frame backchain pointer is left uninitialized (there are also sometimes additional instruction in-between stack frame allocation and backchain write instructions due to gcc shrink-wrapping). In attempt to unwind such stack the unwinder would still try to use that invalid backchain value and perform all kind of sanity checks on it to make sure we are not pointed out of stack. In some cases that invalid backchain value would be 0 and we would falsely treat next stackframe as pt_regs and again gprs[15] in those pt_regs might happen to point at some address within the task's stack. Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: enforce CONFIG_SMP

2019-06-07T08:09:37+00:00

There never have been distributions that shiped with CONFIG_SMP=n for s390. In addition the kernel currently doesn't even compile with CONFIG_SMP=n for s390. Most likely it wouldn't even work, even if we fix the compile error, since nobody tests it, since there is no use case that I can think of. Therefore simply enforce CONFIG_SMP and get rid of some more or less unused code. Reviewed-by: Christian Borntraeger Signed-off-by: Heiko Carstens

s390/unwind: introduce stack unwind API

2019-05-02T11:54:11+00:00

Rework the dump_trace() stack unwinder interface to support different unwinding algorithms. The new interface looks like this: struct unwind_state state; unwind_for_each_frame(&state, task, regs, start_stack) do_something(state.sp, state.ip, state.reliable); The unwind_bc.c file contains the implementation for the classic back-chain unwinder. One positive side effect of the new code is it now handles ftraced functions gracefully. It prints the real name of the return function instead of 'return_to_handler'. Signed-off-by: Martin Schwidefsky

s390/dumpstack: print psw mask and address again

2018-10-10T05:37:20+00:00

With pointer obfuscation the output of show_registers() became quite useless: Krnl PSW : (____ptrval____) (____ptrval____) (__list_add_valid+0x98/0xa8) In order to print the psw mask and address use %px instead of %p. And the output looks again like this: Krnl PSW : 0404d00180000000 00000000007c0dd0 (__list_add_valid+0x98/0xa8) Reviewed-by: Martin Schwidefsky Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky